No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Evolution and evolutionary biostratigraphy of Carboniferous ammonoids.
Abstract
Ammonoids are among the most satisfactory fossils for use in stratigraphic correlation, because of their nektonic mode of life, potential for postmortem distribution and rapid evolution. Many Carboniferous basinal and marginal open-sea faunal successions are dominated by ammonoids, and assemblsages of 10 to 20 genera are not uncommon. Ammonoids, are also abundant in some shelf successions, though virtually absent from others. The richest and best known Carboniferous ammonoid successions are in western Europe, the Soviet Union (South Urals, Donetz Basin and Middle Asia), North America and North Africa (Algeria and Morocco). The appearance of new or modified morphological features provides the basis for recognition of some 12 important events in the evolution of the ammonoids that are common to all these successions. A total of 17 ammonoid-based zones may be used to subdivide the Carboniferous. Since they are founded on evolutionary changes and appear in all successions studied, these division provide a good basis for the erection of intercontinental chronostratigraphic divisions.-Authors Inst Geological Sciences, Leeds LS15 8TQ, UK.
... However, genozones in their current use are not to be considered as a geological series accumulated during the timespan of an index genus, as they are now generally understood as deposits with an assembly of the most characteristic genera, the duration of which does not necessarily precisely coincide with the geological boundaries of the eponymous series Bogoslovskaya 1971, 1978;Popov 1977;Bogoslovskaya et al. 1999). Ramsbottom and Saunders (1985) and Becker and Kullmann (1996) correlated the genozone boundaries with major events in ammonoid evolution, such as the first manifestation of an evolutionarily significant and recognizable morphological character. In that sense, Carboniferous ammonoid genozones were considered as biostratigraphic units, based on evolutionary events. ...
... For example, in Ruzhencev and Bogoslovskaya's (1971) scheme, the Tournaisian-Visean was subdivided into five genozones: Protocanites-Gattendorfia, Pericyclus, Merocanites-Ammonellipsites, Beyrichoceras-Goniatites and Hypergoniatites-Ferganoceras genozones. In Ramsbottom and Saunders's (1985) scheme this interval included six zones: Gattendorfia, Pericyclus, Fascipericyclus-Ammonellipsites, Beyrichoceras, Goniatites and Neoglyphioceras. Kullmann et al. (1990, p. 127) recognized 16 genozones, which were based on Levels that appear to have significance for international correlation are recognized by the entry of Gattendorfia; Paprothites; Pseudarietites; Goniocyclus; Pericyclus; Girtyoceras; Arnsbergites and Paraglyphioceras; Neoglyphioceras; Sulcogirtyoceras; Lusitanoceras and related genera; Dombarites, Ferganoceras and related genera; and Proshumardites, Delepinoceras and glaphyritids. ...
... The Upper Bashkirian, Moscovian, Kasimovian and Gzhelian are mostly continental in Western Europe with some 'marine bands', hence ammonoid genozones for this interval were proposed later and were based on combined evidence of ammonoids from the 'marine bands' of Europe and marine deposits of other regions, mainly North America, Canada, Northeastern Russia and the Donets Basin (Patteisky 1930(Patteisky , 1959(Patteisky , 1964(Patteisky , 1965Jongmans and Gothan 1937;Unklesbay 1954;Bogoslovskaya 1971, 1978;Nassichuk 1975;Popov 1979;Ramsbottom and Saunders 1985). This interval included the Branneroceras-Gastrioceras, Diaboloceras-Axinolobus, Diaboloceras-Winslowoceras, Paralegoceras-Eowellerites, Pseudoparalegoceras-Wellerites, Dunbarites-Parashumardites and Shumardites-Emilites genozones. ...
Considerable progress has been made by international teams in refining the traditional ammonoid zonation that remains the backbone of Carboniferous stratigraphy. The Carboniferous ammonoid genozones, with a few gaps, are now recognized throughout the entire system in most successions worldwide. Refined collecting and documentation of occurrences in Western Europe, North Africa, the Urals, China, and North America, aimed to establish the first evolutionary occurrences, and facilitated correlation with foraminiferal and conodont scales for most of the Carboniferous. From ten to eleven ammonoid genozones are now recognized in the Mississippian, and eight to nine genozones in the Pennsylvanian. Of these, the established lower boundaries of the subsystems are reasonably well correlated with the ammonoid zonation, whereas correlations with the ratified foraminiferal-based lower boundary of the Viséan and other stage boundaries, currently under discussion, need further research. Future success in the ammonoid geochronology will also depend on accurate identification and re-illustration of the type material, including material described by pioneers of ammonoid biostratigraphy.
... In the ammonoid zonation, the Mid-Carboniferous boundary is identified at the base of the Homoceras Zone or Isohomoceras subglobosum Zone of Great Britain, Nevada, and Central Asia ( Ramsbottom and Saunders, 1985;Kullmann and Nikolaeva, 2002). However, it is most likely that the first Isohomoceras subglobosum in Nevada and Central Asia occurs slightly earlier, in the latest Mississippian (Serpukhovian) (Nigmadganov and Nemirovskaya, 1992;Titus and Manger, 2001 Ivanov (1926) was the first to recognize the significant difference between fauna in the limestone of Khamovniki, Dorogomilovo, Voskresensk, and Yauza and fauna from Moscovian strata. ...
... In the ammonoid zonation, the Bashkirian-Moscovian boundary coincides with either the base of the Winslowoceras e Diaboloceras Zone (a zone based on genera, rather than species) on the Russian Platform and Urals (Ruzhenzev and Bogoslovskaya, 1978), or with the Eowellerites Zone in Western Europe and North America (Ramsbottom and Saunders, 1985). It is most likely that the base of the Eowellerites Zone is slightly older than the base of the Winslowoceras e Diaboloceras Zone. ...
... In the ammonite zonation, the Moscovian-Kasimovian boundary is set at the base of the Dunbarites e Para- shumardites Zone (Ruzhenzev, 1974). However, this zone is different from the Parashumardites Zone of Ramsbottom and Saunders (1985), which characterizes the base of the Mis- sourian. The Dunbarites e Parashumardites Zone occurs at the base of the Wewoka Formation of the Desmoinesian (Ruzhenzev, 1974). ...
... The analysis of ammonoid faunas in the Leitrim Group has provided a precise resolution of the upper Viséan biostratigraphy and is compared with studies from northern England and Germany (e.g. Bisat 1924Bisat , 1928Bisat , 1934Bisat , 1952Earp et al. 1961;Ramsbottom and Saunders 1985;Kullmann et al. 1990;Korn 1994;Riley 1990Riley , 1993Riley , 1996. Ammonoids are one of the most reliable faunal groups in Middle Mississippian biostratigraphical correlations, in which zones and subzones can be correlated between different basins (e.g. ...
... Ammonoids are one of the most reliable faunal groups in Middle Mississippian biostratigraphical correlations, in which zones and subzones can be correlated between different basins (e.g. Ramsbottom and Saunders 1985, figure 4). However, ammonoids are more common in relatively deep-water facies, although they also occur occasionally in shallow-water sedimentary rocks, which are present in the Meenymore and Bellavally formations (Brandon 1977;Brandon and Hodson 1984). ...
... Brandon and Hodson (1984) resolved the apparent age disparity of the ammonoid data from the Meenymore Formation (Roscunnish Shale) by considering that Goniatites striatus from the O'Donnell's Rock area (Dixon 1972) should be referred to the Goniatites maximus group (B 2 Zone) and that the Bellavally Formation in this area was in faulted contact with the Meenymore Formation. (1983) considered this zone in Belgium as the Goniatites schmidtianus Zone, equivalent to the G14 Zone of Ramsbottom and Saunders (1985); nevertheless most authors consider currently that G. schmidtianus is synonymous with G. ...
The microbiota of the upper Viséan (Asbian–Brigantian) rocks in the Lough Allen Basin in northwest Ireland is analysed. The Middle Mississippian sequence studied extends from the upper part of the Dartry Limestone/Bricklieve Limestone formations of the Tyrone Group to the Carraun Shale Formation of the Leitrim Group. The rocks have been traditionally dated by ammonoid faunas representing the B2a to P2c subzones. The Meenymore Formation (base of the Leitrim Group) also contains conodont faunas of the informal partial-range Mestognathus bipluti zone. The upper Brigantian Lochriea nodosa Conodont Zone was recognized by previous authors in the middle of the Carraun Shale Formation (Ardvarney Limestone Member), where it coincides with upper Brigantian ammonoids of the Lusitanoceras granosus Subzone (P2a). Foraminifera and algae in the top of the Dartry Limestone Formation are assigned to the upper Cf6γ Foraminifera Subzone (highest Asbian), whereas those in the Meenymore Formation belong to the lower Cf6δ Foraminifera Subzone (lower Brigantian). The Dartry Limestone Formation–Meenymore Formation boundary is thus correlated with the Asbian–Brigantian boundary in northwest Ireland. For the first time, based on new data, a correlation between the ammonoid, miospore, foraminiferan and conodont zonal schemes is demonstrated. The foraminiferans and algae, conodonts and ammonoids are compared with those from other basins in Ireland, northern England, and the German Rhenish Massif. Historically, the Asbian–Brigantian boundary has been correlated with several levels within the P1a Ammonoid Subzone. However, the new integrated biostratigraphical data indicate that the Asbian–Brigantian boundary in northwest Ireland is probably located within the B2a Ammonoid Subzone and the NM Miospore Zone, but the scarcity of ammonoids in the Tyrone Group precludes an accurate placement of that boundary within this subzone. Copyright © 2006 John Wiley & Sons, Ltd.
... occurs 9.4 m above the Isohomoceras subglobosum Marine Band. Hence, the base of the Bashkirian Stage may not coincide in the ammonoid zonation with the base of the Homoceras Zone or I. subglobosum Zone of Great Britain, Nevada, and Central Asia (Ramsbottom and Saunders, 1985;Kullmann and Nikolaeva, 2002). Manger (2017) stated that the occurrence of I. subglobosum is earlier in Central Asia and Nevada (Nemirovskaya and Nigmadganov, 1994;Titus et al., 1997) than in western Europe. ...
... Historically, the stratigraphic divisions in the pelagic facies were based on ammonoids (e.g., Bisat, 1924Bisat, , 1928Schmidt, 1925). Ammonoids have been provided very detailed biostratigraphic schemes in western Europe (e.g., Ramsbottom and Saunders, 1985;Korn, 1996Korn, , 2006, eastern Europe (e.g., Ruzhenzev, 1965;Ruzhenzev and Bogoslovskaya, 1978;Nikolaeva et al., 2009a), Northern Africa (e.g., Ebbighausen and Bockwinkel, 2007;Korn et al., 2007), and northern America (e.g., Korn and Titus, 2011;Boardman and Work, 2013). Korn and Klug (2015) noted that ammonoid faunas are recorded from many regions in Mississippian and Bashkirian strata, but they become progressively rarer in their distribution and by the end of the Carboniferous rich faunas are only known from the American midcontinent, the southern Urals, and Uzbekistan. ...
The Carboniferous Period experienced recovery and major diversification in the marine and terrestrial realms after the end-Devonian mass extinctions. Marked evolutions took place in the terrestrial realm with the development of extended forests and the appearance of reptiles and the first flying organisms. Strong faunal provincialism resulted from geodynamic and climatic changes during the Visean. The Carboniferous Period is also characterized by the onset of the Late Paleozoic Ice Age with characteristic glacial—interglacial cycles, the closure of the western Paleotethys Ocean, and the Variscan orogeny.
... 1; 1996, textfig. 3), ammonoids do not readily define the Tournaisian-Viséan (early-late Chadian) boundary (Ramsbottom and Saunders, 1985), and correct age assignment of isolated boundary faunas is commonly dependent on complementary evidence from other fossil groups that can be related to the Belgian standard. ...
... An upper Osagean faunule described by Gordon (1965) Gordon, 1965) which occur with brachiopods of lower Keokuk (early late Osagean) aspect, according to Gordon (1965, p. 13). This interval, known as the Ammonellipsites ballardensis Zone (Ramsbottom and Saunders, 1985, fig. 4 ...
... The Big Snowy Group as a whole is Serpukhovian in age. Biostratigraphic studies of the Heath Formation based upon conodonts (Scott, 1973), brachiopods (Lutz-Garihan, 1985), bryozoa (Cuffey, personal communication), palynomorphs (Cox, 1986), and cephalopods (Ramsbottom and Saunders, 1985;Saunders, written communication) agree with this correlation. The Serpukhovian is the upper stage of the Mississippian and is dated between 328.3 and 318.1 Mya (Ogg et al., 2008;ICS, 2010). ...
... The cephalopod fauna of the Bear Gulch lens is most similar to that of the Imo formation of Arkansas (Saunders, written communication), which is placed in the Upper Chesterian goniatite zone E2b-E2c. The Imo Formation is placed in Mamet's foraminiferal zone 19 (Brenckle, 1977;Hoare and Mapes, 2000), which had an estimated duration of~2 Myr (Dutro, 1985), but the goniatite cephalopod zones of the Namurian of Northwestern Europe are less than 25,000 years in duration (Ramsbottom and Saunders, 1985), and the Bear Gulch lens represents only a small fraction of this stratigraphic interval. These observations, together with the work of Haq and Schutter (2008), support Williams's (1981) estimate that a minimum of 1000 years and a maximum of less than 25,000 years were necessary to deposit the entire Bear Gulch lens. ...
... The question of the base of Bashkirian was discussed above. The different concepts of the base of the Reticuloceras zone by Ruzhencev and Bogoslavskaya (1978), on the one hand, and by Ramsbottom and Saunders (1985), followed by Kullmann (2002), Kullmann and Nikolaeva (2002), on the other, is the next question. In this paper the opinion of the latter authors is accepted, i.e. the Homoceras-Hudsonoceras Zone is extended to the upper limit of the Alportian. ...
... It is discussed as important for the stratigraphic positions of the corals studied herein and in the subsequent papers on the Early Bashkirian Rugosa from the Donets Basin. Ramsbottom and Saunders (1985) equated the R1/R2 boundary (Reticuloceras-Bashkortoceras/ Bilinguites-Cancelloceras) with the beginning of the Marsdenian, whereas Ruzhencev and Bogoslavskaya (1978) and Kullmann and Nikolaeva (2002) elevated that boundary to the middle of the Marsdenian. The latter option opens the question of the upper limit of the Kamennogorskian Substage from the South Urals and its correlation with both the Krasnopolyanian and the Severokeltmenian substages in central Russia and the Western European stages. ...
The present paper is the first in a series devoted to the Early Bashkirian Rugosa (Anthozoa) fromthe Donets Basin. The history of investigation and current status of Early Bashkirian stratigraphy is discussed in the context of the Donets Basin strata. Corals of that time interval are extremely rare worldwide and those from the Donets Basin have never been described in detail. Four of the five species described are new: Rotiphyllum asymmetricum sp. nov., R. latithecatum sp. nov., R. simulatum sp. nov., and R. voznesenkae sp. nov. Two species are left in open nomenclature. The synonymy, species content and critical review of species potentially belonging to the genus Rotiphyllum are reviewed.
... K U L AG I NA A N D OT H E R S Declinognathodus noduliferus (Ellison & Graves, 1941) in Unit G (sample 61b) in the Bird Spring Formation (Lane et al. , 1999Lane & Manger, 1985;Brenckle et al. 1997;Richards et al. 2002). This boundary closely coincides in time with the first appearance of the ammonoid family Homoceratidae (Bisat, 1924(Bisat, , 1928Ruzhencev & Bogoslovskaya, 1978;Manger & Saunders, 1982;Pareyn et al. 1984;Manger et al. 1985;Ramsbottom & Saunders, 1985;Kulagina et al. 1992;Nikolaeva, 1994Nikolaeva, , 1995aRiley, 1998;Titus et al. 1997;Titus & Manger, 2001). Other sections containing the boundary level and proposed as possible candidates included successions in Britain (Riley, 1987;Riley et al. 1987), China (Li et al. 1987), the Donets Basin, Ukraine (Aizenverg et al. 1983;Skipp et al. 1989) and Uzbekistan (Nigmadganov & Nemirovskaya, 1992;Nikolaeva & Nigmadganov, 1992;Nikolaeva, 1994Nikolaeva, , 1995a. ...
... Both these species appear at this level in many sections of the South Urals, Central Asia and North Africa near the Mid-Carboniferous Boundary . The Nm1c2 Zone corresponds to the upper part of the E2 Zone of Western Europe (Bisat, 1924(Bisat, , 1928Ramsbottom & Saunders, 1985;Nikolaeva & Kullmann, 1998, etc.). 4.c.2. ...
The uninterrupted succession of the Mississippian–Pennsylvanian boundary beds in the
Muradymovo section in the South Urals contains diverse fossils and has a high correlative potential.
The Muradymovo section is located in the Zilair Megasynclinorium (ZM), which belongs to the West
Uralian Subregion and displays carbonate-siliciclastic deep-water facies of the Bukharcha Formation,
which is partly Serpukhovian (Kosogorian, Protvian and Yuldybaevian) and partly Bashkirian (Syuranian).
In the southern ZM, the lower part of the formation contains argillaceous carbonates with beds
of shale and siltstone, subordinate clastic limestones and limestone breccia, while the upper part is
mostly limestone with cherty interbeds. In the north of the ZM, the formation mainly consists of limestone.
The Muradymovo succession contains no identifiable gaps in the Mid-Carboniferous Boundary
(MCB) portion and has a succession of foraminiferal, conodont, ammonoid and ostracod zones. The
MCB in this section coincides with the base of the Bogdanovkian and is defined by the entry of Declinognathodus
noduliferus. This level falls within the upper part of the foraminiferal Monotaxinoides
transitorius Zone, is near the base of the ammonoid Homoceras–Hudsonoceras Genozone and can be
correlated worldwide.
... The Big Snowy Group as a whole is Serpukhovian in age. Biostratigraphic studies of the Heath Formation based upon conodonts (Scott, 1973), brachiopods (Lutz-Garihan, 1985), bryozoa (Cuffey, personal communication), palynomorphs (Cox, 1986), and cephalopods (Ramsbottom and Saunders, 1985;Saunders, written communication) agree with this correlation. The Serpukhovian is the upper stage of the Mississippian and is dated between 328.3 and 318.1 Mya (Ogg et al., 2008;ICS, 2010). ...
... The cephalopod fauna of the Bear Gulch lens is most similar to that of the Imo formation of Arkansas (Saunders, written communication), which is placed in the Upper Chesterian goniatite zone E2b-E2c. The Imo Formation is placed in Mamet's foraminiferal zone 19 (Brenckle, 1977;Hoare and Mapes, 2000), which had an estimated duration of~2 Myr (Dutro, 1985), but the goniatite cephalopod zones of the Namurian of Northwestern Europe are less than 25,000 years in duration (Ramsbottom and Saunders, 1985), and the Bear Gulch lens represents only a small fraction of this stratigraphic interval. These observations, together with the work of Haq and Schutter (2008), support Williams's (1981) estimate that a minimum of 1000 years and a maximum of less than 25,000 years were necessary to deposit the entire Bear Gulch lens. ...
The Bear Gulch Limestone of Montana preserves a Late Mississippian (318 Mya) tropical marine bay in its entirety and provides a rare picture of vertebrate community structure and diversity in deep time. Decades of quarrying has produced over 5700 fish of 149 species from nine habitat zones within the bay. The fish fauna differs from that of modern faunas in that Coelacanthiformes form the most abundant guild and Chondrichthyes comprise the group with the most species and genera and exhibit the greatest spectrum of adaptive suites.Within the bay ecosystem, strong differences in habitats were reflected in equally strong differences in composition and distribution of the fishes on the generic and suprageneric levels. Genus richness within each habitat was high. The upper bay assemblages were the most distinct in terms of both their supported fish fauna and environments; Acanthodes comprised a significant fraction of the fauna in these zones. Across the bay, Chondrichthyes and Osteichthyes showed markedly different responses to environmental variation at both local and regional scales. For both clades, dominant genera occurred ubiquitously across the bay, but showed habitat-related trends in their distribution. Rare genera comprised an unusually large proportion of total genus richness and exhibited a high degree of habitat preference. This research also includes an initial assessment of the impact of the predominance of ecologically rare taxa on the quantitative estimation of biodiversity.
... The Big Snowy Group as a whole is Serpukhovian in age. Biostratigraphic studies of the Heath Formation based upon conodonts (Scott, 1973), brachiopods (Lutz-Garihan, 1985), bryozoa (Cuffey, personal communication), palynomorphs (Cox, 1986), and cephalopods (Ramsbottom and Saunders, 1985;Saunders, written communication) agree with this correlation. The Serpukhovian is the upper stage of the Mississippian and is dated between 328.3 and 318.1 Mya (Ogg et al., 2008;ICS, 2010). ...
... The cephalopod fauna of the Bear Gulch lens is most similar to that of the Imo formation of Arkansas (Saunders, written communication), which is placed in the Upper Chesterian goniatite zone E2b-E2c. The Imo Formation is placed in Mamet's foraminiferal zone 19 (Brenckle, 1977;Hoare and Mapes, 2000), which had an estimated duration of~2 Myr (Dutro, 1985), but the goniatite cephalopod zones of the Namurian of Northwestern Europe are less than 25,000 years in duration (Ramsbottom and Saunders, 1985), and the Bear Gulch lens represents only a small fraction of this stratigraphic interval. These observations, together with the work of Haq and Schutter (2008), support Williams's (1981) estimate that a minimum of 1000 years and a maximum of less than 25,000 years were necessary to deposit the entire Bear Gulch lens. ...
Quarrying operations for fossil fish from the Bear Gulch Limestone (Heath Formation, Namurian,Montana, USA) have occurred from 1968 to 1997 and continue. The Bear Gulch Limestone lens (14×9 km) thins to a shore line on all edges except the buried eastern boundary, and contains an entirely marine flora and fauna. Eighty outcrops have been sampled, and 4 547 identifiable fish of 113 taxa have been recorded. This study details aspects of the diversity and distribution of the fishes of the Bear Gulch Bay analyzed on the basis of geographic areas, following facies and sedimentary criteria. The total diversity of the fish fauna is 21.08 (Simpson index) and 12.07 (Margalef index). Diversity decreases from east to west and towards the southern margin. These trends mask dramatic differences in species occurrences and dominant species in each area. The high diversity of the “Depocenter” area can be accounted for by its proximity to the mouth of the bay and access to the epicontinental seaway to the east. The southeast region is comprised of the Blacktail, Allen, and Buchek areas. Diversity declines greatly from the algae - and sponge - rich Blacktail area southwestward to the marginal Buchek area. This region contains several dominant species that are adapted to lurk in or maneuver among plants, feed from the bottom or burrow. High numbers of larval paleoniscoids and the coelacanth Caridosuctor lower the diversity of the near-shore North Shore area. The western end of the bay is dominated by Acanthodes,, scales of Listracanthus and Strepsodus,, and large cladodont sharks. Fish distributions, preliminary assessments of morphological adaptations, and facies all support the concept of a heterogeneous set of habitats within this fossil bay.
... Macrofauna associated with the marine bands form the basis of a high-resolution biostratigraphic framework through the Namurian (Holdsworth and Collinson, 1988;Ramsbottom and Saunders, 1985). Marine bands and overlying mudstones exhibit the following idealized faunal sequence (phases 6 to 1); thick shelled ammonoids (6), thin shelled ammonoids (5), molluscan spat (4), lingula (3), planolites (2), fish remains (1) and barren zones (Baines, 1977;Ramsbottom et al., 1962;Ramsbottom, 1977). ...
We conducted a high-resolution multi-disciplinary analysis of two core sections in the borehole Ellesmere Port-1, Cheshire, UK. Biostratigraphic analysis indicates the core sections are Kinderscoutian and late Arnsbergian-Chokerian in age, respectively. Both cores are assigned to the Bowland Shale Formation (Holywell Shale). Coupled core scan and discrete geochemical analysis enables interpretation of syngenetic processes at a high stratigraphic resolution. Both cores exhibit the classic cyclicity of limestones, calcareous to non-calcareous mudstones and siltstones, interpreted to represent sediment deposition during fourth-order sea level fluctuation. Machine learning of the well log data coupled to the core scan data enabled prediction of the key lithofacies through the entire Bowland Shale interval in Ellesmere Port-1. The machine predictions show the Bowland Shale is interfingered with three turbiditic leaves of the Cefn-y-fedw Sandstone Formation and contains at least 12 complete fourth-order cycles. The Bowland Shale exhibits high radiogenic heat productivity (RHP) in comparison to other sedimentary rocks, due primarily to relative enrichment in U under intermittently euxinic conditions. Thermal modelling, however, shows Bowland Shale RHP contributes a negligible source of additional heat at the scale of 100s m.
Supplementary material at https://doi.org/10.6084/m9.figshare.c.6911105
... Waters et al. 2009). Macrofaunal body fossils, particularly ammonoids, are used to construct a high-resolution biostratigraphic framework (Ramsbottom and Saunders 1985). However, the macrofaunal index fossils can be difficult to recognize in cores (Riley 1993;Waters et al. 2009;Clarke et al. 2018). ...
The Bowland sub-basin is a target for hydrocarbon exploration but to a large extent it remains unexplored. To determine the economic potential of the Bowland sub-basin, it is important to identify the oceanographic processes involved in the deposition of the Bowland Shale Formation in the Late Mississippian ( ca . 330 Ma). Palaeoceanographic processes are known to be a major control on the development of hydrocarbon source rocks. This study investigates core (Preese Hall-1 and Becconsall-1Z) materials from the Upper Bowland Shale, and compares to previously published data (outcrop Hind Clough), all from the Bowland sub-basin, Lancashire, UK. The sedimentology and geochemistry of this formation was determined via a multi-technique approach including x-ray fluorescence (XRF), sedimentology, gamma ray spectra, x-ray diffraction (XRD) and RockEval(6) TM pyrolysis. Key trace metal abundances and enrichment factors were used to assess sediment provenance and to determine the bottom water redox conditions during the deposition of the Upper Bowland Shale. Our results support interpretations that contemporaneous anoxia developed in bottom waters in at least three sites in the Bowland sub-basin. In a comparison with the Fort Worth Basin (Barnett Shale, USA), the Bowland sub-basin was apparently less restricted and deposited under a much higher mean sediment accumulation rate compared to the Fort Worth Basin. Knowledge from this study improves future resource estimates of the Bowland Shale Formation, and challenges the early assumptions that the Barnett Shale is an analogue to the Bowland Shale.
... Marine bands typically include thick-and thin-shelled body fossils hosted within a weakly to moderately lenticular, typically carbonaterich, mud-rich matrix (Emmings et al., 2019a). Macrofaunal body fossils, particularly ammonoids, are used to differentiate marine bands from intervening mudstones and permit a high-resolution biostratigraphic framework (Ramsbottom and Saunders, 1985). The Upper Bowland Shale in the study area contains four index marine bands, E 1a 1 to E 1c 1, which correspond to the base of four ammonoid (sub)zones, Cravenoceras leion, Cravenoceras bradoni, Tumulites pseudobilinguis and Cravenoceras malhamense, respectively (e.g., Brandon et al., 1998). ...
Early diagenetic redox oscillation processes have been rarely recognised in the ancient rock record but potentially exert an important control on mineral authigenesis, hydrocarbon prospectivity and supply of metals and/or reduced S as part of associated mineral systems. The upper unit of the Mississippian Bowland Shale Formation is a candidate record of diagenetic redox oscillation processes because it was deposited under a relatively high sediment accumulation rate linked to a large delta system, and under dominantly anoxic and intermittently sulphidic bottom-water conditions. In order to characterise the syngenetic and early diagenetic processes, sedimentological and geochemical data were integrated through the Upper Bowland Shale at three sites in the Craven Basin (Lancashire, UK). Organic matter (OM) comprises a mixture of Type II, II-S, II/III and III OM. ‘Redox zones’ are defined by patterns of Fe-speciation and redox-sensitive trace element enrichment and split into two groups. ‘Sulphidic’ zones (EUX, AN-III, AN-I and AN-IT) represent sediments deposited under conditions of at least intermittently active sulphate-reduction in bottom-waters. ‘Non-sulphidic’ zones (OX-RX, OX-F and OX) represent sediments deposited under non-sulphidic (oxic to ferruginous anoxic) bottom-waters. Operation of a shelf-to-basin ‘reactive Fe’ (FeHR) shuttle, moderated by sea level fluctuation and delta proximity, controlled the position and stability of redoxclines between zones of Fe and sulphate reduction, and methanogenesis. Early diagenetic redoxclines were capable of migration through the shallow sediment column relatively quickly, in response to sea level fluctuation. Preservation of syngenetic and early diagenetic geochemical signals shows redoxclines between Fe and sulphate reduction, and the upper boundary of sulphate-methane transition zone, were positioned within decimetres (i.e., 10 s cm) of seabed. Falling sea level and increasing FeHR supply is recognised as a switch from zones EUX (high sea level), AN-III and ultimately AN-I and AN-IT (low sea level). Zone AN-I defines the operation of ‘redox oscillation’, between zones of Fe and sulphate reduction in shallow porewaters, associated with enhanced degradation of OM and complete dissolution of primary carbonate. Preservation of OM and carbonate, in this system, was a function of changing bottom and pore water redox processes. Redox oscillation operated in a siliciclastic, prodeltaic environment associated with a relatively high sediment accumulation rate and high loadings of labile organic matter and metal oxides. These findings are important for understanding Late Palaeozoic black shales in the context of hydrocarbon and mineral systems.
... Marine bands typically include thick-and thin-shelled body fossils hosted within a weakly to moderately lenticular, typically carbonaterich, mud-rich matrix (Emmings et al., 2019a). Macrofaunal body fossils, particularly ammonoids, are used to differentiate marine bands from intervening mudstones and permit a high-resolution biostratigraphic framework (Ramsbottom and Saunders, 1985). The Upper Bowland Shale in the study area contains four index marine bands, E 1a 1 to E 1c 1, which correspond to the base of four ammonoid (sub)zones, Cravenoceras leion, Cravenoceras bradoni, Tumulites pseudobilinguis and Cravenoceras malhamense, respectively (e.g., Brandon et al., 1998). ...
Organic‐rich mudstones have long been of interest as conventional and unconventional source rocks and are an important organic carbon sink. Yet the processes that deposited organic‐rich muds in epicontinental seaways are poorly understood, partly because few modern analogues exist. This study investigates the processes that transported and deposited sediment and organic matter through part of the Bowland Shale Formation, from the Mississippian Rheic–Tethys seaway. Field to micron‐scale sedimentological analysis reveals a heterogeneous succession of carbonate‐rich, siliceous, and siliciclastic, argillaceous muds. Deposition of these facies at basinal and slope locations was moderated by progradation of the nearby Pendle delta system, fourth‐order eustatic sea‐level fluctuation and localized block‐and‐basin tectonism. Marine transgressions deposited bioclastic ‘marine band' (hemi)pelagic packages. These include abundant euhaline macrofaunal tests, and phosphatic concretions of organic matter and radiolarian tests interpreted as faecal pellets sourced from a productive water column. Lens‐rich (lenticular) mudstones, hybrid, debrite and turbidite beds successively overlie marine band packages and suggest reducing basin accommodation promoted sediment deposition via laminar and hybrid flows sourced from the basin margins. Mud lenses in lenticular mudstones lack organic linings and bioclasts and are equant in early‐cemented lenses and in plan‐view and are largest and most abundant in mudstones overlying marine band packages. Thus, lenses likely represent partially consolidated mud clasts that were scoured and transported in bedload from the shelf or proximal slope, as a ‘shelf to basin' conveyor, during periods of reduced basin accommodation. Candidate in situ microbial mats in strongly lenticular mudstones, and as rip‐up fragments in the down‐dip hybrid beds, suggest that these were potentially key biostabilizers of mud. Deltaic mud export was fast, despite the intrabasinal complexity, likely an order of magnitude higher than similar successions deposited in North America. Epicontinental basins remotely linked to delta systems were therefore capable of rapidly accumulating both sediment and organic matter. This article is protected by copyright. All rights reserved.
... The macrofaunal body fossils present, particularly ammonoids, form the basis of a high-resolution biostratigraphic framework (Ramsbottom and Saunders, 1985). The ammonoid biozones E 1a1 , E 1b1 , E 1b2 and E 1c1 are recognized in the Upper Bowland Shale (e.g., Brandon et al., 1998) (Fig. 1c), with an average periodicity of 111 ka (Waters and Condon, 2012). ...
Paleoredox proxies (Fe speciation, trace element and δ34Spy) integrated with sedimentological and palynological observations link the distribution and type of particulate organic matter (OM) preserved to hydrocarbon source rock potential. In the Mississippian Bowland Shale Formation (Lancashire, UK), particulate OM is dominated by “heterogeneous” amorphous OM (AOM), primarily “sharp-edged, pellet-like” (AOMpel) and “heterogeneous, granular” (AOMgr) types. AOMpel is abundant in muds deposited under anoxic and moderately to highly sulphidic conditions and most likely represents the fecal minipellets of zooplankton and/or pellets of macro-zooplankters. We recognize two intervals, “A” and “B,” which exhibit Sorg/TOC > 0.04, suggesting a bulk Type II-S kerogen composition. The Interval A palynofacies is typified by pyritized AOMpel (AOMpyr) particles that contain high-relief organic spheres surrounding individual pyrite framboids, within each AOMpyr particle. These textures are interpreted as sulphurized OM local to pyrite framboids (Sorg-PF). Sorg-PF is rarely observed in Interval B, and absent in all other samples. Redox oscillation between ferruginous and euxinic conditions during early diagenesis of Interval A likely promoted S cycling in microenvironments surrounding pyrite framboids, which generated reactive S species and reactive OM required for sulphurization. Early diagenetic redox oscillation processes were apparently triggered by relative sea level fall, associated with an increased supply of FeHR from adjacent shelves into the basin. Interval B represents deposition during the late stages of basin infill and transition from anoxic to (sub)oxic bottom waters, where AOMpel is replaced by AOMgr as the dominant type of AOM. A large particle diameter at the limit of the mesh size (500 μm), sheet-like, fragmented character, and presence of candidate organic sheaths suggests AOMgr at least partially represent fragments of benthic microbial mats, probably as sulphide-oxidizers. A ternary plot of AOMpel + AOMpyr versus AOMgr versus spores + phytoclasts links the observed palynofacies to bottom and pore water redox conditions, water column productivity and proximity to fluvial (deltaic) supply of spores and phytoclasts. These variables were moderated by changing basin accommodation, driven primarily by eustatic sea level fluctuation. A sequence-stratigraphic control on AOM type and sulphurization is important for understanding the link between source rock heterogeneity and the timing of hydrocarbon generation and expulsion from this source rock.
... Reticuloceras? compressum is found below the R. inconstans Zone in Blackburn (Lancashire, England; Bisat and Hudson 1943) as well as below the first appearance of R. circumplicatile in Clare, Ireland (Hodson 1957), along with V. henkei, H. magistrorum, and Paradimorphoceras looneyi (Phillips 1836). This level was proposed several times as an alternative base for the Reticuloceras Zone (Hodson 1957;Ramsbottom and Saunders 1985). Waters et al. (2011) accepted this position of the zonal boundary in Britain as the same level as the base of the Kinderscoutian Stage (Cleal and Thomas 1996). ...
TheKugarchi Section in the Zilair Synclinorium in the SouthUrals (Russia, Bashkortostan) is one of themost complete sections of the Bukharcha Formation, including the entire Serpukhovian and the lower Bashkirian. This is the type section of the Bogdanovkian Regional Infrasubstage (‘Horizon’), the lowermost Bashkirian of the Urals. The section spans the Visean–Serpukhovian and Mid-Carboniferous boundaries and contains various ammonoids, conodonts, and foraminifers, providing a good basis for the regional stratigraphy and global correlations. The section has been measured and logged, and its microfacies and fossils are identified in this study.
... The identification of 'marine bands' (glacioeustatic flooding surfaces; e.g., Ramsbottom, 1977;Davies, 2008), containing diagnostic faunal (ammonoid) assemblages, permits correlation across the Craven Basin and in some instances across several basins (Ramsbottom and Saunders, 1985;Waters and Condon, 2012). From the Lower Bowland Shale (P2c ammonoid zone) to the base of the Pendleton Formation (cutting into E1c ammonoid zone), the dominant mudstone lithology is exposed almost continuously within a perennial stream section and adjacent slope exposure (Fig. 1b). ...
This study contributes to the exploration and quantification of the weathering of organic-rich mudstones under temperate climatic conditions. Bowland Shales, exposed by a stream and slope, were sampled in order to develop a model for the effects of weathering on the mudstone geochemistry, including major and trace element geochemistry, Rock-Eval pyrolysis and δ¹³Corg. Four weathering grades (I - IV) are defined using a visual classification scheme; visually fresh and unaltered (I), chemically altered (II, III) and 'paper shale' that typifies weathered mudstone on slopes (IV). Bedload abrasion in the stream exposes of visually fresh and geochemically unaltered mudstone. Natural fractures are conduits for oxidising meteoric waters that promote leaching at the millimetre scale and/or precipitation of iron oxide coatings along fracture surfaces. On the slope, bedding-parallel fractures formed (and may continue to form) in response to chemical and/or physical weathering processes. These fractures develop along planes of weakness, typically along laminae comprising detrital grains, and exhibit millimetre- and centimetre-scale leached layers and iron oxide coatings. Fracture surfaces are progressively exposed to physical weathering processes towards the outcrop surface, and results in disintegration of the altered material along fracture surfaces. Grade IV, 'paper shale' mudstone is chemically unaltered but represents a biased record driven by initial heterogeneity in the sedimentary fabric. Chemically weathered outcrop samples exhibit lower concentrations of both 'free' (S1) (up to 0.6mgHC/g rock) and 'bound' (S2) (up to 3.2mgHC/g rock) hydrocarbon, reduced total organic carbon content (up to 0.34wt%), reduced hydrogen index (up to 58mgHC/gTOC), increased oxygen index (up to 19mgCO+CO2/gTOC) and increased Tmax (up to 11°C) compared with unaltered samples. If analysis of chemically weathered samples is unavoidable, back-extrapolation of Rock-Eval parameters can assist in the estimation of pre-weathering organic compositions. Combining Cs/Cu with oxygen index is a proxy for identifying the weathering progression from fresh material (I) to 'paper shale' (IV). This study demonstrates that outcrop samples in temperate climates can provide information for assessing hydrocarbon potential of organic-rich mudstones.
... (3) The next level upward in the section is that with Proshumardites fraudulentus of the Fayettevillea -Delepinoceras Genozone and is most probably equivalent to that of the Nm1c2 Zone of the South Urals Bed 26 (Verkhnyaya Kardailovka section) in the Chernyshevian (Yuldybaevian) Horizon. In Western Europe equivalent faunas are found in the upper part of the Е2 Zone of the British Isles (Bisat, 1924(Bisat, , 1928Hudson, 1945;Currie, 1954;Ramsbottom, 1969;Ramsbottom and Saunders, 1985;Riley, 1987), and in the USA in the Eumorphoceras girtyi, Cravenoceratoides nititoides, and Delepinoceras thalassoide Zones (Gordon, 1965;Miller and Youngquist, 1948;Elias, 1956;Titus, 2000). Gibshman and Pazukhin (2003) in the Verkhnyaya Kardailovka Section (Nikolaeva et al., 2001) andMuradymovo Section (Kulagina et al., 1992). ...
NIGMADHAZNOV, I.M., NIKOLAEVA, S. V., KONOVALOVA V. A., and ORLOV-LABKOVSKY, O. Integrated ammonoid, conodont and foraminiferal stratigraphy in the Paltau section, Middle Тien-Shan, Uzbekistan. Newsletter on Carboniferous Stratigraphy, 28: 51–61.
... More than 500 species belonging to about 85 goniatitid and 13 prolecanitid genera are recorded almost exclusively from the Northern Hemisphere. A great number of species and genera are used as index fossils for global ammonoid zonation in the Goniatites Stufe, Pendleian, and Arnsbergian stages (Kullmann, 1962;Bogoslovskaya, 1971, 1978;Ramsbottom and Saunders, 1985). ...
Paleozoic ammonoids have attracted much less attention from professional and amateur paleontologists than Mesozoic ammonoids. Because of the Variscan folding in Europe, the classical area of investigation, Devonian and Carboniferous material from Europe is often rather poorly preserved. As a result, few collectors of the 19th and early 20th century have focused their attention on these fossils. In recent decades, however, as our knowledge of Paleozoic ammonoids has expanded, it has become more and more apparent that the evolution and systematics of Paleozoic forms are as complex as those of Mesozoic ones. For example, the number of Devonian genera rose from about 80 in the Treatise of 1957 to a present figure of more than 200.
... 5 .2 C A R B O N I F E R O U S S T R A T I G R (Wedekind, 1918;Bisat, 1924Bisat, , 1928Schmidt, 1925;Ramsbottom and Saunders, 1985) and in the entire Carboniferous in eastern Europe (Ruzhenzev, 1965;234 PART III geologic: periods Ruzhenzcv and Bogoslovskaya, 1978) have served as chronosrrati graphic standards in inter-regional and global correlation ( Fig. 15.1 ...
... 5 .2 C A R B O N I F E R O U S S T R A T I G R (Wedekind, 1918;Bisat, 1924Bisat, , 1928Schmidt, 1925;Ramsbottom and Saunders, 1985) and in the entire Carboniferous in eastern Europe (Ruzhenzev, 1965;234 PART III geologic: periods Ruzhenzcv and Bogoslovskaya, 1978) have served as chronosrrati graphic standards in inter-regional and global correlation ( Fig. 15.1 ...
The supercontinent Pangea formed. Major changes in ocean circulation; biogeographic differentiation; high bio-provincialism; diversification of land plants and increased continental weathering rates and storage of organic carbon as coal; drawdown of atmospheric CO2 and significant cooling, major glaciation, and sharp sea-level fluctuations; cyclic marine sequences; appearance of reptiles (with amniotic egg reproduction) and occupation of new (dry-land) niches; extinction or decreasing role of early Paleozoic biota such as stromatoporids, tabulate corals, trilobites, ostracods, heavily armored marine fish; appearance or very rapid diversification of foraminifera, ammonoids, fresh water pelecpods, gastropods, sharks, ray-finned fishes, and wingless insects. Late Carboniferous–Early Permian Kiaman Superchron is the longest known period of predominantly reversed polarity. HISTORY AND SUBDIVISIONS Because of climatic variability, the Carboniferous was a time of incredible diversification and abundant terrestrial biota. It signifies Earth's first episode of massive coal formation. The commercial production of coal led to the early development of Carboniferous stratigraphic classifications in three major regions: western Europe, eastern Europe, and North America.
... Late Viséan (Goniatites and Neoglyphioceras genus zones sensu Ramsbottom and Saunders, 1985) ammonoids are widespread in foreland basin settings around the margin of the North American continent and have been described or illustrated from the Chainman Shale of Nevada and Utah (Miller et al., 1949(Miller et al., , 1952Gordon, 1965Gordon, , 1971Furnish and Saunders, 1971;Titus and Riley, 1997), the Barnett Shale of central Texas (Smith, 1903;Plummer and Scott, 1937;Miller and Youngquist, 1948;Miller and Downs, 1950;Plummer, 1950;Elias, 1956;Gordon, 1960Gordon, , 1965, the Caney Shale of Oklahoma (Girty, 1909;Miller and Furnish, 1940a;Gordon, 1962Gordon, , 1965Branson, 1964;McCaleb et al., 1964;Saunders et al., 1977;Korn et al., 2004), the Moorefield Formation of Arkansas (Girty, 1911;Gordon, 1965;Saunders et al., 1977), the Pride Mountain Shale of Alabama (Drahovzal, 2009), the Newman Limestone and equivalent formations of Kentucky (Miller and Faber, 1892;Miller and Gurley, 1896;Smith, 1903;Miller and Furnish, 1940a;McCaleb et al., 1964;Gordon, 1965;Furnish and Saunders, 1971;Titus and Riley, 1997;Work and Mason, 2009b), and the Ste. Genevieve Limestone of Illinois and Indiana (Smith, 1903;Collinson, 1955). ...
Mid-Carboniferous strata of the Barnett Shale in the Sierra Diablo region are deep water, offshore sediments
deposited in the Marathon Foreland Basin. These strata contain a remarkably complete ammonoid record spanning from the Late Viséan to the middle Atokan (Moscovian). Late Viséan strata are referred to as the “Folks Member” of the Barnett Shale and locally yield numerous ammonoids. Three assemblages can be recognized, which contain, from oldest to youngest, Goniatites eganensis and Girtyoceras hamiltonense (Goniatites eganensis Zone), Goniatites multiliratus and Girtyoceras meslerianum (Goniatites multiliratus Zone), and Choctawites cumminsi and Pachylyroceras cloudi (Choctawites cumminsi Zone). We erect the new genera Choctawites and Uralyroceras to accommodate, respectively, the North American species “Goniatites choctawensis Shumard, 1863”, “G. kentuckiensis Miller, 1889” and “G. cumminsi Hyatt, 1893”, and Uralian species formerly attributed to Pachylyroceras. For the material of “Pachylyroceras cloudi” of the South Urals, the new species name Uralyroceras arquatum is proposed.
... compressum also contains Vallites henkei, Hodsonites magistrorum and Paradi morphoceras looneyi; it lies 0.3 m below the band with Reticuloceras circumplicatile. HODSON (1954HODSON ( ,1957, CALVER & RAMSBOTTOM (1961) and RAMSBOTTOM & SAUNDERS (1985) consid ered this level as the base of the R j Zone since it could be easily recognized in most succes sions, including Blackburn. ...
Thl; stratigraphical range and the boundaries of the Middle Namurian ammonoid Reticuloceras
Zone are reviewed, and the ammonoid occurrences indicating this interval are documented. The richest
ammonoid occurrences are recovered from the South Urals, whereas the highest precision of
ammonoid-based biostratigraphy is achieved in Britain. Three subdominant zones are recognizable within
the Reticuloceras Zone in both successions, but their boundaries do not correspond exactly. The lowermost
occurrence of reticuloceratids (Reticuloceras ? compressum) in Western Europe occurs slightly lower
than the entry of the coarsely-ornamented and widely umbilicate ammonoid Phillipsoceras circumplicatile
which is commonly associated with the base of the Kinderscoutian. This level apparently correlates with
the first appearance of reticuloceratids in the South Urals, but it lies above the lower boundary of the" Reticuloceras-
Bashkortoceras Genus Zone" of RUZHENTSEV. The appearance of Bilinguites bilinguis marks the
beginning of the following Upper Namurian"Bilinguites-Cancelloceras Genus Zone".
... A third inconvenience is the strong facies control on the ammonoid faunas but this is a similar problem observed in other Carboniferous fossil groups. Nevertheless, ammonoid zonal schemes similar to the British one have been used successfully in Morocco and Algeria (e.g., Pareyn, 1961;Lemosquet et al., 1985;Korn et al., 2007;Korn and Ebbighausen, 2008;Wendt et al., 2009), and the British ammonoid succession has been correlated with Germany (e.g., Korn, 1996Korn, , 2006Korn and Horn, 1997), the Urals (Nikolaeva et al., 2009a) and North America (Ramsbottom and Saunders, 1985;Richards and Task Group, 2009). ...
—The Carboniferous succession in Adarouch (Central Morocco, north of the Atlas Transform Fault) contains thick carbonate beds including upper Visean, Serpukhovian and basal Bashkirian rocks. Foraminifers enable precise recognition of the Visean/Serpukhovian (V/S), early/late Serpukhovian (eS/lS) and Serpukhovian/
Bashkirian (S/B) boundaries. Insolentitheca horrida, Loeblichia ukrainica, ‘‘Millerella’’ spp. and Endostaffella? sp. 2 are regarded as regionally useful indices to the V/S boundary, whereas Eostaffellina spp., Eostaffella pseudostruvei and some evolved species of Archaediscus exhibit greater reliability for worldwide correlation of this level. Similarly, the eS/lS boundary is marked locally by Brenckleina rugosa, Eosigmoilina sp., and Monotaxinoides spp. and globally by Loeblichia minima, Bradyina cribrostomata, Plectostaffella spp., Eostaffellina ‘‘protvae’’ and ‘‘Turrispiroides’’, and the S/B boundary is marked locally by Globivalulina bulloides and globally by Seminovella elegantula, and Novella? Occurrences of these taxa in Morocco allow correlations with the Moscow Basin, the Urals, the Donetz Basin and North America. The Moroccan assemblages share few taxa in common with Saharan basins south of the Atlas Transform Fault. Correlations with western European basins are difficult because of the paucity in the latter of foraminiferal-bearing carbonate strata.
This volume showcases recent geological, geophysical, and geochemical research on the Carboniferous Bowland Shale Formation, a classic Palaeozoic black shale unit. The Bowland Shale spans ca. 16 Myrs from the upper Visean to mid-Bashkirian, and is perhaps the most important and controversial black shale unit in the UK. The volume focuses on the key Carboniferous basins in the Midlands, northern England, and North Wales. The main basins assessed in the volume are the Craven Basin, including the Bowland sub-basin, the Blacon Basin, the Edale Basin, the Widmerpool Gulf and the Gainsborough Trough. The Bowland Shale and equivalent units are described and interpreted in terms of sedimentary, geochemical, and physical properties and processes, basin-forming events, hydrocarbon prospectivity, mineralization, and heat and fluid flow in the subsurface.
We evaluated the unconventional hydrocarbon potential of the Holywell Shale Formation, a lateral equivalent of the Bowland Shale Formation deposited in the Blacon Basin. Two cores with Arnsbergian–Chokierian and Kinderscoutian (Namurian, Late Mississippian–Early Pennsylvanian) ages from the Ellesmere Port 1 borehole were sampled for palynological, stable isotope, Rock-Eval 6 pyrolysis and ichnofacies analyses. The study was designed to provide boundary conditions for parameters that are under-represented in the public domain and hamper accurate resource assessments: thermal maturity (through mean random vitrinite reflectance, R r ), present-day organic matter content, kerogen type, original hydrogen index and original organic matter content. Our results show that the Arnsbergian Core 2 has been buried to a depth equivalent to the bottom of the oil window to the top of the gas window (% R r = 1.15%–1.29%). The Kinderscoutian Core 1 is too immature to have generated any natural gas (% R r = 0.91–1.03%). Furthermore, kerogen typing and ichnofacies analysis show that the Bowland Shale Formation is very heterogeneous, with organic matter originating from terrestrial and marine sources. Five palynofacies assemblages are described that range in basin setting from proximal and oxic to distal and anoxic with evidence of episodic connections to the open ocean. The combination of heterogeneity and low thermal maturity restricts the thickness of the Bowland Shale Formation in the Blacon Basin that is prospective for unconventional hydrocarbons. Our results show that these Carboniferous mudstones should not be treated as uniform units with uniform composition and maturity in basin modelling and resource estimates. This undoubtedly has repercussions for future exploration because the contrasting composition and density of the materials making up the Bowland Shale Formation may complicate extraction, while the thermal maturity window significantly narrows the prospective interval.
Los ammonoideos son proxies muy recurridos en la estratigrafía por ser considerados importantes fósiles índice. Debido a su relevancia, en este trabajo se realizó una revisión exhaustiva de los reportes de ammonoideos presentes en afloramientos del Carbonífero y Pérmico de México. Se contemplaron las localidades del Anticlinorio Huizachal-Peregrina en Tamaulipas y Santiago Ixtaltepec en Oaxaca para el Carbonífero; así como las localidades de El Antimonio en Sonora, Las Delicias en Coahuila, Placer de Guadalupe en Chihuahua, San Salvador Patlanoaya en Puebla, Olinalá en Guerrero y Chicomuselo en Chiapas para el Pérmico. Los resultados arrojaron seis familias, seis géneros y seis especies para el Carbonífero, mientras que para el Pérmico se registraron 13 familias, 24 géneros y 47 especies. Con respecto a los nombres específicos, se sugiere revisar la clasificación de diferentes registros desactualizados. En cuanto a la bioestratigrafía, se reconocieron cuatro zonas de ammonoideos para el Carbonífero, abarcando desde el Viseano (Misisípico Medio) hasta el Gzheliano (Pensilvánico Superior); mientras que para el Pérmico se reconocieron de seis a ocho zonas, abarcando desde el Sakmariano hasta el Wuchiapingiano. Asimismo, se llevó a cabo una búsqueda de los registros mexicanos del Carbonífero-Pérmico para otras regiones del mundo; además se discute acerca de la paleobiogeografía del grupo, resaltando una mayor afinidad con las biotas reportadas en diversas localidades del Paleozoico tardío de los Estados Unidos. A pesar de que los ammonoideos no son clave para determinar un paleoambiente de depósito, dada su abundancia en zonas relacionadas con aguas someras o cercanas a bancos de arena o arrecifales, y su evidente ausencia en facies de ambientes profundos, se señala que durante el Carbonífero–Pérmico pudo haber existido cierta preferencia de dichos organismos por habitar ambientes someros.
It is increasingly clear that present-day dynamic topography on Earth, which is generated and maintained by mantle convective processes, varies on timescales and length scales on the order of 1−10 m.y. and 10^3 km, respectively. A significant implication of this behavior is that Phanerozoic stratigraphic records should contain indirect evidence of these processes. Here, we describe and analyze a well-exposed example of an ancient landscape from the Grand Canyon region of western North America that appears to preserve a transient response to mantle processes. The Surprise Canyon Formation lies close to the Mississippian-Pennsylvanian boundary and crops out as a series of discontinuous lenses and patches that are interpreted as remnants of a westward-draining network of paleovalleys and paleochannels within a coastal embayment. This drainage network is incised into the marine Redwall Limestone whose irregular and karstified upper surface contains many caves and collapse structures. The Surprise Canyon Formation itself consists of coarse imbricated conglomerates, terrestrial plant impressions including Lepidodendron, and marine invertebrate fossils. It is overlain by marine, fluvial, and aeolian deposits of the Supai Group. These stratal relationships are indicative of a transient base-level fall whose amplitude and regional extent are recognized as being inconsistent with glacio-eustatic sea-level variation. We propose that this transient event is caused by emplacement and decay of a temperature anomaly within an asthenospheric channel located beneath the lithospheric plate. An analytical model is developed that accounts for the average regional uplift associated with landscape development and its rapid tectonic subsidence. This model suggests that emplacement and decay of a ∼50 °C temperature anomaly within a channel that is 150 ± 50 km thick can account for the observed vertical displacements. Our results are corroborated by detrital zircon studies that support wholesale drainage reorganization at this time and by stratigraphic evidence for spatially variable regional epeirogeny. They are also consistent with an emerging understanding of the temporal and spatial evolution of the lithosphere-asthenosphere boundary.
The Naqing section in southern Guizhou Province is one of the two leading Viséan-Serpukhovian boundary GSSP candidates. The nearby Narao section is the auxiliary section. The conodont biostratigraphy of the Viséan-Serpukhovian boundary interval at the Narao section has been preliminarily established, and the conodont zones can be correlated with those of the Naqing section. The FAD of L. ziegleri in the L. nodosa-L. ziegleri chronocline at 41.8 m marks the base of the Serpukhovian Stage at this section. In this study, 28 species of 23 foraminiferal genera have been recovered from the Viséan-Serpukhovian boundary interval. Two foraminiferal zones, Asteroarchaediscus rugosus Zone and Janischewskina delicata Zone, are recognized. A. rugosus Zone is the youngest Viséan foraminiferal zone. J. delicata Zone is the oldest Serpukhovian foraminiferal zone. The FAD of J. delicata at 44 m defines the base of the J. delicata Zone. The co-occurrence of typical Serpukhovian conodont L. ziegleri and foraminfera J. delicata within 2.2 meters of the boundary interval provides significant information of the correlation between conodont and foraminifera near the Viséan-Serpukhovian boundary.
The stratotype for the Bashkirian Stage of the Soviet Middle Carboniferous is located on the Askyn River in Gornaya Bashkiria (western slope of south Urals). Twenty-four rock samples, mostly from the lower part of the section, yielded abundant and diverse assemblages of calcareous foraminifers which are systematically described and illustrated here for the first time.
The foraminiferal assemblage from the Siuransky Horizon at the base of the Bashkirian is essentially identical to that from the top of the underlying Lower Carboniferous Serpukhovian Stage. Thus, foraminifers do not provide a basis for identifying the Soviet Lower–Middle Carboniferous boundary. This notwithstanding, the presence of the foraminifer Globivalvulina bulloides (Brady) (= G. moderata Reitlinger) and the conodont Idiognathodus parvus (Dunn) in both the upper Serpukhovian and Bashkirian indicates that the base of the Bashkirian can be no older than medial to late Morrowan of the North American succession. The primitive fusulinid Pseudostaffella ( Pseudostaffella ) appears at the bases of the lower Bashkirian Akavassky Horizon and the North American Atokan Series. The base of the Akavassky is interpreted to be somewhat older than early Atokan, however, because Ps. ( Pseudostaffella ) appeared in the Urals in phylogenetic continuity with its immediate ancestor, whereas in most of North America it was an immigrant.
The type Bashkirian succession contains a seemingly complete phylogeny from advanced eostaffellids to primitive fusulinids. Plectostaffella jakhensis , immediate ancestor to the fusulinids, arose from a member of the Eostaffella postmosquensis plexus in the late Serpukhovian. Plectostaffella jakhensis , in turn, gave rise to Ps. ( Semistaffella ) variabilis in the early Bashkirian (late Siuransky), from which evolved Ps. ( Ps. ) antiqua shortly thereafter (earliest Akavassky). An as yet unidentified but advanced species of Ps. ( Pseudostaffella ) is the most likely ancestor to late Bashkirian Neostaffella ivanovi . The evolutionary series leading from the E. postmosquensis plexus to primitive Neostaffella apparently developed exclusively in the Eurasian–Arctic faunal realm, as Pl. jakhensis, Ps. ( Semistaffella ) variabilis , and Ps. ( Ps. ) antiqua are unknown in the Midcontinent–Andean region. Diverse Ps. ( Pseudostaffella ) spp. appeared in the latter area pursuant to an adaptive radiation aided by periodic interchange between faunal realms.
Lithostratigraphic and chronostratigraphic subdivisions of the Price Formation in West Virginia are presented. On the basis of lithostratigraphic and biostratigraphic correlations the Oswayo Formation, Cussewago Sandstone, Riddlesburg Shale, and Rockwell Formation of western and central Pennsylvania are recognized as members of the Price in northern West Virginia. In southern West Virginia the Cloyd Conglomerate Member and Sunbury Shale Member of the Price Formation in Virginia are recognized in addition to the undivided upper
portion of the Price. The rocks of the Price in West Virginia bear a greater lithologic similarity to the roc;ks of the Price Formation in Virginia than they do to the recently redefined Pocono Formation in northeastern
Pennsylvania. For this reason, the use of the terms Pocono Formation and Pocono Group in West Virginia should be abandoned.
Rocks of the nearshore facies of the Sunbury transgression are recognized over much of the outcrop belt in West Virginia. These rocks comprise an important stratigraphic datum that when used in conjunction with
biostratigraphic data permits chronostratigraphic subdivision of the marine facies of the Price in West Virginia. In northern West Virginia, marine rocks range from late Famennian to early Kinderhookian time, whereas those in southern West Virginia range from early Kinderhookian to early Osagean time.
The reticuloceratid ammonoid Arkanites relictus (Quinn, McCaleb, and Webb, 1962) is represented by hundreds to thousands of individuals from horizons isolated both stratigraphically and geographically in northern Arkansas. These assemblages appear to represent mass mortality events resulting from a semelparous reproductive strategy. Arkanites relictus occurs as a dimorphic pair (depressed, widely umbilicate, cadiconic conchs and compressed, narrowly umbilicate, pachyconic conchs) thought to reflect sexual dimorphism. Late stage ontogenetic modifications, such as septal crowding and change in aperture profile, are widely cited evidence of sexual maturity in ammonoids. Septal crowding begins at a predictable ontogenetic stage in the compressed forms of A. relictus, but specimens with cadiconic conchs do not have crowded septa even at the largest diameters available.
Depending on the trait examined and the proxy for age of individuals, the dimorphism in Arkanites relictus (using the depressed form as the reference morph) is the result of acceleration, neoteny, or hypermorphosis plus neoteny. If size (diameter) is considered a proxy for age, the dimorphs were the same age at death, and the septa in the compressed variants developed via acceleration relative to the depressed variants. Regarding conch shape (width vs. diameter), the compressed morphs developed via neoteny relative to the depressed morphs. If septal count is considered a proxy for age, the dimorphs were not the same age at death, and the compressed forms were produced by a combination of hypermorphosis plus neoteny, i.e., they grew longer yet slower than the depressed forms. In A. relictus, the heterochronic processes of hypermorphosis and neoteny may have been operating simultaneously, which is an interesting possibility because it is an example of a combination of both peramorphic and paedomorphic processes.
The most widely cited explanation for the functional enigma of sutural complexity in ammonoids, the Buckland hypothesis, has related septal folding and fluting to buttressing. Comparison of shell and septum thickness with sutural complexity in 49 Paleozoic ammonoid genera indicates that no significant reduction in either septum thickness or shell thickness accompanied a one-hundred-fold increase in sutural complexity. These preliminary results fail to support the Buckland hypothesis and add support to views that septal fluting may have been related to buoyancy control. -Author
Latest Devonian to early Late Carboniferous palynozones of northern Brazilian basins are revised and correlated with equivalent miospore biozones of western Europe. It is concluded that certain biozones in PETROBRAS' earlier regional scheme for the Lower Carboniferous are actually indistinguishable, because age implications and stratigraphic ranges of their zonal species are now known to differ markedly from those given in older Brazilian literature. A regional unconformity separates Late Visean strata from early Late Tournaisian or older sediments in the Amazon and western Solimoes Basins, as possibly also in the Parnaiba Basin. Marine faunal controls for Late Carboniferous carbonates, within sections of Amazonian basins which contain taeniate pollen, are partly discussed with reference to U.S. Midcontinent data, and demonstrated to exclude pre-Westphalian age assignments. On the other hand, a possible Late Namurian age is acceptable from the palynological viewpoint for the oldest, dominantly terrigenous part of the Late Carboniferous sequence in the Solimoes Basin. This lacks taeniate bisaccates and seems to have no sedimentary equivalent in the neighbouring Amazon Basin. Results of the present study indicate that additional palynological investigations are needed in Early and Late Carboniferous sections of the Parnaiba and Solimoes Basins.
A successor to A Geologic Time Scale 1989 (Cambridge, 1990), this volume introduces the theory and methodology behind the construction of the new time scale, before presenting the scale itself in extensive detail. An international team of over forty stratigraphic experts develops the most up-to-date international stratigraphic framework for the Precambrian and Phanerozoic eras. A large wallchart (not available for eBook) summarizing the time scale at the back of the book completes this invaluable reference for researchers and students.
The ammonoid order Prolecanitida constitutes a relatively small (43 genera, ∼250 species) but long-ranging lineage (Lower Carboniferous-Triassic, ∼108 m.y.), which narrowly survived the P/Tr extinctions and provided the stock from which were derived all later Mesozoic ammonoids. Prolecanitids were a minority among Late Paleozoic ammonoids, which were dominated by the Goniatitida, and showed many features that set them far apart from their contemporaries, including (1) long-term, gradual changes in shell geometry (W-D-S); (2) the most strongly constrained morphospace of any Paleozoic ammonids examined to date; (3) an eight-fold increase in mean suture complexity (three times that of Pennsylvanian goniatitids); (4) high correlations between shell geometry, shell and septal thickness, and suture complexity; (5) short body chambers and as a consequence, high aperture orientations; (6) indications that cameral liquid may have been used for buoyancy control; and (7) a genus longevity that averaged 14.7 m.y. compared with 5.7 m.y. in Upper Carboniferous goniatitids, and that appears to have been unrelated to suture complexity. Prolecanitids showed a pervasive tendency to increase suture complexity (in the clade as a whole as well as within subclades and in more than 90 percent of ancestor-descendant genera), thus arguing a case for a driven complexity trend. The uniqueness of the prolecanitids calls into question whether they and their Mesozoic descendants, ceratites and ammonites, were strictly analogous to Paleozoic goniatites.
Principal components analysis of Upper Carboniferous (Pennsylvanian) ammonoids (all 117 genera), using 21 variables to measure shell geometry, sculpture and suture complexity, shows that following a sharp decline (∼30%) in generic diversity after the mid-Carboniferous boundary, seven morphotypes persisted throughout the Pennsylvanian (ca. 30 m.y.). Six of these were polyphyletically adopted at different times, while the seventh was monopolized by the prolecanitids, a group whose evolution accelerated during the Pennsylvanian and later gave rise to Mesozoic ammonoids. Innovations in suture geometry distinguished at least 17 of 39 (44%) Pennsylvanian ammonoid families. Average suture complexity increased almost threefold; this was achieved by various methods (lobe serration, insertion of umbilical elements, prong subdivision, lobe trifurcation, and secondary bifurcation), which were recurrent and crossed morphotype boundaries. The Pennsylvanian record supports suggestions that Paleozoic ammonoids were confined to a certain suite of basic shell geometries, showing preference for a limited number of sites in the spectrum of available morphospace. However, these morphic constraints did not, with one possible exception (the prolecanitids), control the emergence of increasing sutural complexity during the Pennsylvanian, which occurred among different lineages in all seven morphotypes.
The reticuloceratid ammonoid Arkanites relictus (Quinn, McCaleb, and Webb, 1962) is represented by hundreds to thousands of individuals from horizons isolated both stratigraphically and geographically in northern Arkansas. These assemblages appear to represent mass mortality events resulting from a semelparous reproductive strategy. Arkanites relictus occurs as a dimorphic pair (depressed, widely umbilicate, cadiconic conchs and compressed, narrowly umbilicate, pachyconic conchs) thought to reflect sexual dimorphism. Late stage ontogenetic modifications, such as septal crowding and change in aperture profile, are widely cited evidence of sexual maturity in ammonoids. Septal crowding begins at a predictable ontogenetic stage in the compressed forms of A. relictus, but specimens with cadiconic conchs do not have crowded septa even at the largest diameters available. Depending on the trait examined and the proxy for age of individuals, the dimorphism in Arkanites relictus (using the depressed form as the reference morph) is the result of acceleration, neoteny, or hypermorphosis plus neoteny. If size (diameter) is considered a proxy for age, the dimorphs were the same age at death, and the septa in the compressed variants developed via acceleration relative to the depressed variants. Regarding conch shape (width vs. diameter), the compressed morphs developed via neoteny relative to the depressed morphs. If septal count is considered a proxy for age, the dimorphs were not the same age at death, and the compressed forms were produced by a combination of hypermorphosis plus neoteny, i.e., they grew longer yet slower than the depressed forms. In A. relictus, the heterochronic processes of hypermorphosis and neoteny may have been operating simultaneously, which is an interesting possibility because it is an example of a combination of both peramorphic and paedomorphic processes.
The stratigraphical distribution of trilobites in the Dinantian succession of the Peak District is summarised. Six new species of early Carboniferous trilobites: Bollandia columba, Bollandia rugiceps, Cummingella sampsoni, Griffithides whitewatsoni, Namuropyge glaphyra and Piltonia paucita are described. -Author
Vaughan's (1905) zonation of the Carboniferous Limestone in the Bristol district was a pioneer biostratigraphical study, which because of its meticulous execution can be reinterpreted in a modern context. The replacement of his scheme with a chronostratigraphical one by George et al. (1976) had a similar revolutionary affect on British Dinantian stratigraphy. However, it is now time to revise the British Dinantian stages so that they more closely correspond to biostratigraphical events. Dinantian biostratigraphy still requires considerable refinement, but it has now achieved a diversity of techniques and resolution far beyond that which was available at the time of these earlier proposals. It is the most pragmatic and closest approximation to widespread chronostratigraphical correlation available. This paper discusses these and related issues and presents a review and correlation of current biozonations.
The so-called “Namurian” taeniate bisaccates newly reported from the Amazon Basin of northern Brazil (Marques-Toigo et al. 1995) are demonstrated to be not older than Westphalian in the light of revised foraminiferal and palynological evidence. Nevertheless, marine microfossil data supports a slightly older age assignment (Westphalian A-B) than miospores (Westphalian C). Correlations of Carboniferous pollen assemblages in the Amazon Basin with those from the Paraná Basin, in southeastern and southern Brazil, are hindered by the absence of diagnostic marine microfossils and coeval mid-Carboniferous strata in the latter.
Palynology represents the standard tool for subsurface biostratigraphical correlation of Euramerican Late Carboniferous sequences. While palynomorphs are usually absent from sandstone lithologies, they form diverse and abundant assemblages in fine-grained sediments and coals. The occurrence of inter- and intrasandstone horizons that contain distinctive palynological assemblages forms the basis for the correlation and discrimination of sandstone reservoirs, and the application of palynology to development drilling programmes. The successful application of development palynology is contingent upon many factors related to geology (sandstone-body type, occurrence and lateral consistency of distinctive horizons, nature of intrareservoir units, degree of reservoir incision, etc.) and to practical constraints (such as the nature of databases, sampling strategies with ditch cuttings, standardization of preparation and data acquisition techniques, and time and cost limitations). The development palynologist needs to be critically aware of the existence of such constraints, and should limit the confidence attached to interpretations and predictions made accordingly.
A brachiopod fauna spanning the Tournaisian-Visean boundary is reported from the Southern Tienshan Mountains of Xinjiang, NW China. This fauna exhibits strong generic and specific links with coeval North American faunas. The present fauna is of close affinity with those of the northern Tienshan and Junggar Basin rather than that of the Tarim Basin. Biogeographically, the southern and northern Tienshan areas belong to the Tienshan-Hinggan Province of the Boreal Realm during the Tournaisian and Visean, while the adjacent Tarim Basin belongs to the Tethyan Province of the Tethyan Realm, which differs from the conclusions of previous studies. Two now species are proposed: Spirifer (Spirifer) gancaohuensis and Kitakamithyris karatagensis.
The ammonoid faunas from the Goniatites Zone (Late Visean; Mississippian) of the Camp Canyon Member (Chainman Formation) are described for the first time. The assemblage shows close relationships to time equivalent occurrences in Alaska and the American Midcontinent, but differs markedly from occurrences in Europe, North Africa, and the South Urals. Seven successive ammonoid biozones are proposed for this interval in North America, in ascending order: (1) Calygirtyoceras confusionense Ammonoid Biozone, (2) Calygirtyoceras arcticum Ammonoid Biozone, (3) Girtyoceras primum Ammonoid Biozone, (4) Girtyoceras gordoni Ammonoid Biozone, (5) Goniatites deceptus Ammonoid Biozone, (6) Goniatites eganensis Ammonoid Biozone, and (7) Goniatites multiliratus Ammonoid Biozone. The following ammonoid species are revised or newly described: Bollandoceras occidentale sp. nov., Entogonites burbankensis sp. nov., Entogonites borealis (Gordon, 1957), Entogonites acus sp. nov., Calygirtyoceras confusionense sp. nov., Calygirtyoceras arcticum Gordon, 1957, Girtyoceras primum sp. nov., Girtyoceras gordoni sp. nov., Girtyoceras hamiltonense sp. nov., Dimorphoceras worki sp. nov., Dimorphoceras rileyi sp. nov., Metadimorphoceras mangeri sp. nov., Metadimorphoceras richardsi sp. nov., Kazakhoceras bylundi sp. nov., Goniatites americanus Gordon, 1971, Goniatites deceptus sp. nov., Goniatites eganensis sp. nov., Goniatites sowerbyi sp. nov., and Praedaraelites loeblichi (Miller & Furnish, 1940).
A uniquely complete carbonate sequence spanning a large portion of the Viséan and the entire Serpukhovian is exposed on the Ural River, opposite the village of Verkhnyaya Kardailovka (South Urals, Bashkortostan, Russia). The Upper Viséan and Serpukhovian beds in this section are composed of deep-water carbonates containing ammonoids, conodonts, ostracodes and foraminifers. The section is well-sampled, measured, its lithology is now described, and a sedimentary environment near the seaward end of a carbonate platform and deep shelf is suggested. Abundant fossils allow the recognition of four successive ammonoid and four successive conodont zones, which allow reliable correlations of the regional Serpukhovian stages outside the South Urals, although the type section of the Serpukhovian in the Moscow Basin is in the shallow-water facies. The base of the Serpukhovian in the Moscow Basin and in the South Urals is defined by the first appearance datum (FAD) of the conodont Lochriea ziegleri. This level coincides with the base of the Kosogorskian in the Urals, correlates with the entry of the foraminifer "Millerella" tortula near the base of the Tarusian in the Moscow Basin and is close to the earliest occurrences of Dombarites paratectus and Cravenoceras at the base of the Uralopronorites-Cravenoceras Genozone and of the latter genus at the base of the British E1 Zone. Because of its accessibility, abundant fossils, and its well studied lithology, the Verkhnyaya Kardailovka Section is an excellent candidate for the GSSP of the Viséan-Serpukhovian boundary.
ResearchGate has not been able to resolve any references for this publication.