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The biostratigraphic record of Cretaceous to Paleogene tectono-eustatic relative sea-level change in Jamaica
Abstract
The island of Jamaica forms the northern extent of the Nicaraguan Rise, an elongate linear tectonic feature stretching as far as Honduras and Nicaragua to the south. Uplift and subaerial exposure of Jamaica during the Neogene has made the island rare within the Caribbean region, as it is the only area where rocks of the Nicaraguan Rise are exposed on land. Biostratigraphic dating and palaeoenvironmental interpretations using larger benthic foraminifera, supplemented by planktonic foraminifera, nannopalaeontology and palynology of outcrop, well and corehole samples has enabled the creation of a regional relative sea-level curve through identification of several depositional sequences. This study recognises ten unconformity-bounded transgressive-regressive sequences which record a complete cycle of relative sea level rise and fall. Sequences are recognised in the Early to ‘Middle’ Cretaceous (EKTR1), Coniacian-Santonian (STR1), Campanian (CTR1), Maastrichtian (MTR1-2), Paleocene-Early Eocene (PETR1), Eocene (YTR1-3) and Late Eocene-Oligocene (WTR1). These transgressive-regressive cycles represent second to fourth order sequences, although most tie with globally recognised third order sequences. Comparisons of the Jamaican relative sea-level curve with other published global mean sea-level curves show that local tectonics exerts a strong control on the deposition of sedimentary sequences in Jamaica. Large unconformities (duration >1 Ma) are related to significant regional tectonic events, with minor overprint of a global eustatic signal, while smaller unconformities (duration <1 Ma) are produced by global eustatic trends. The relatively low rates of relative sea-level rise calculated from the regional relative sea-level curve indicate that carbonate production rates were able to keep pace with the rate of relative sea-level rise accounting for the thick successions of Maastrichtian carbonates and those of the Yellow and White Limestone Groups. Carbonate platform drowning within the White Limestone Group during the Oligocene to Miocene is attributed to environmental deterioration given the low rates of relative sea-level rise.
... Sawkins 1869) to our current understanding. In particular, new or relevant datasets available include those on igneous petrology (Hastie et al. , 2008(Hastie et al. , 2009(Hastie et al. , 2010a(Hastie et al. , b, c, 2011(Hastie et al. , 2012Lewis et al. 2011), metamorphic petrology (Abbott et al. 1996(Abbott et al. , 1999(Abbott et al. , 2003(Abbott et al. , 2013West et al. 2014), sedimentary successions (Mitchell 1999(Mitchell , 2002(Mitchell , 2013a(Mitchell , b, 2016Mitchell and Ramsook 2009;Brown and Mitchell 2010;Fisher and Mitchell 2012;Mitchell et al. 2012;Mitchell and Edwards 2016) and biostratigraphy (Montgomery and Pessagno 1999;Robinson and Mitchell 1999;Gunter 2002;Gunter et al. 2002;Gunter 2002, 2006;Gunter and Mitchell 2005;Mitchell 2005Mitchell , 2009aMitchell , 2009bMitchell , 2010Mitchell and Ramsook 2009;Gold et al. 2018(but see Mitchell 2018 for discussion)). Cretaceous rocks are exposed in a series of inliers across the island (Fig. 2), and to understand their geology the various datasets need to be integrated to form a coherent model, which this manuscript seeks to do. ...
... Biostratigraphic data comes from radiolarians, planktic foraminifers and LBFs (Table 1) and indicates an age range from Turonian to late Campanian (with the distinctive Radotruncana calcarata (Cushman) being common in the higher limestones). Gold et al. (2018) reported early Maastrichtian planktic foraminifers, but recollection of the entire limestone sequence (twice) demonstrated only Coniacian to late Campanian stratigraphy to be represented. At present a satisfactory resolution to this age discrepancy is not possible. ...
... Locally shoals of oolitic grainstone are present, suggesting high-energy environments close to a carbonate platform margin. Gold et al. (2018) assigned this limestone to the Cenomanian, which is in conflict with the fossils (rudists bivalves such as Caprinuloidea and Coalcomana: Mitchell 2018) that are present. The associated clastic rocks consist of shales, sandstones and minor conglomerates and have been placed in the basal part of the Rio Nuevo Formation. ...
This paper provides new data on the Cretaceous geology together with existing data to define four terranes for the Cretaceous of Jamaica. The Northeast Blue Mountain Terrane (NEBMT) contains a shallow-water pile of Campanian basaltic and andesitic lavas interbedded with shallow-water, rudist-bearing limestones. The Southeast Blue Mountain Terrane (SEBMT) contains plume-related basalts attributed to the Caribbean Large Igneous Province (CLIP) of Turonian–Coniacian age overlain by interbedded cherts, limestones and basalts with CLIP affinity of Coniacian–Campanian age; the overlying succession is provisionally attributed to the late Campanian to Maastrichtian. The Western Blue Mountain Terrane (WBMT) contains a suite of Campanian arc rocks intruded by granodiorites which have tectonic contacts with metamorphic rocks (high pressure–low temperate blueschists, amphibolites and greenschists). The Western Jamaica Terrane (WJT) contains a suite of volcanic arc rocks in the Valanginian–Hauterivian, Barremian, Turonian, Santonian to Campanian, and Maastrichtian to Paleocene. These rocks are interbedded with thick to very thick (up to several kilometres) sedimentary sequences which occur at outcrop and in hydrocarbon exploration wells. Three major unconformities are present in the WJT, at the bases of the Crofts Synthem (earliest Campanian), Kellits Synthem (late Campanian to early Maastrichtian) and Yellow Limestone (late Paleocene to early Eocene). The NEBMT and SEBMT are separated from the WBMT and WJT by a NE–SW, left-lateral transform fault that defined the edge of the Caribbean Plate from the early(?) Cretaceous to the mid Eocene and allowed the Cuban oceanic arc and eastern Jamaican terranes to be emplaced between the Americas. Metamorphism in the WBMT indicates the existence of a northeasterly dipping subduction zone which allowed the subduction of CLIP lithosphere in the Campanian. Rudist bivalves suggest an affinity between Jamaica and the Siuna (Chortis) and Guerrero (Mexico) terranes in the Lower Cretaceous, suggesting that these arcs were close together. Subsequently, the three unconformities record interactions between the Jamaican arc segment and the Chortis Block and finally the collision with the Jamaican arc segment with the Maya Block in the Paleocene. The petroleum geology of each Cretaceous terrane is reviewed in the context of source and reservoir rocks. Possible source rocks exist in the Jurassic under northern Jamaica, the Albian to Turonian interval, which is associated with oceanic anoxic events, and the Maastrichtian, which contains thin units of organic-rich shales. Reservoirs are largely confined to limestones which preserve porosity in the body chambers of rudist bivalves and which have also been locally dolomitized and fractured (increasing both porosity and permeability). Oil-associated gas seeps present at outcrop, and oil shows of Jurassic and Cretaceous age from exploration wells indicate the existence of active petroleum systems, but not necessarily of economic hydrocarbon accumulations.
... A C C E P T E D ACCEPTED MANUSCRIPT Gold et al. (2018) use a carbonate ramp model for the mid Cretaceous to Paleogene successions in Jamaica based on the modern slope from the Nicaragua Rise into the Colombian Basin (Arden Jr., 1975;Hine et al., 1992). While certain intervals in the stratigraphic history of Jamaica might be modelled by the use of a carbonate ramp (e.g., the Maastrichtian Guinea Corn Formation and some parts of the Yellow Limestone Group); such a model is unlikely to fit the total sedimentary succession of Jamaica. ...
... There is also a question of the picking of storm wave base in the tropics where storm waves likely affect bottom waters to depths of at least 50-100 m in the modern Atlantic and Gulf of Mexico (Peters and Loss, 2012), not 30-50 m as suggested by Gold et al. (2018, section 4.1). Gold et al. (2018) argue for a high-resolution biostratigraphy, yet seem to base their ages largely on Larger Benthic Foraminifers (LBFs), and mostly (all?) specimens in random cuts in thin section. Many biostratigraphically important taxa cannot be distinguished in random cuts (e.g., the distinction between late Eulinderina and Polylepidina and between Polylepidina and Lepidocyclina ariana) unless fortunate equatorial sections are found. ...
... Detailed/high resolution biostratigraphic work requires the study of isolated specimens (which can be collected from most rocks in Jamaica) to acquire high resolution biostratigraphic data (e.g., Krijnen, 1972Krijnen, , 1978Krijnen et al., 1993;Gunter et al., 2002;Mitchell, 2005;Robinson and Jiang, 1995;Robinson, 1997a, b). The range chart Gold et al. (2018, fig. 3) is clearly low resolution, at best at stage resolution, and lacks many important taxa (e.g., Heterostegina ocalana, Fabularia verseyi, etc.). It is difficult to understand how the lengths of unconformities can be estimated when index taxa range over many millions of years. ...
Gold et al. (2018) present a mid Cretaceous-early Cenozoic relative sea-level curve for Jamaica based on sedimentological and biostratigraphic data from spot samples made from Jamaican outcrop localities and well/corehole samples. They base their work on 200 samples from field outcrops and 600 samples from hydrocarbon exploration wells (many of the latter with cuttings contaminated with extensive cavings)/coreholes, of which 266 were assigned a depositional setting, palaeobathymetry and biostratigraphic age. Gold et al. (2018) use this dataset to revise the sequence stratigraphy of Jamaica, develop a relative sea-level curve and compare this with global sea-level curves. The paper by Gold et al. (2018) includes numerous errors of fact and doubtful interpretations. In this comment I highlight some of these problems based on my own, and my research students’ research over the last 22 years, my own collection of 20,000 + samples from Jamaica, and a thorough understanding of the literature.
... The fabulariids were represented in the American province by endemic species, such as F. vaughani Cole, F. cassis, F. colei and F. verseyi. These species are only found in the Caribbean region (Drobne and Ćosović, 2009;Powell, 2010;Gold et al., 2018) from the Early to Middle Eocene (PZ P6 -P12a). In the Middle Eocene, Lutetian (PZ P10), the biloculine Fabularia (Fig. 7) gave rise to Pseudofabularia (Plate 3, fig. ...
... In the Paleocene Periloculina and Pseudolacazina echoed the Cretaceous forms, but they uniquely gave rise to Paleogene Lacazina and Lacazinella by gradual ontogenetic transformation from pluri-to unilocular, completely overlapping growth. The two chambers per whorl is a key-characteristic of the megalospheric forms in the fabulariid, however, in The re-appeared Lacazina is first recorded in Tethys from the Selandian (PZ P4a), while Lacazinella, having completely overlapping chambers, is rare in the Tethyan province and has not been found in Europe, but is only recorded from Oman and other parts of the Middle East On the other hand, the American Fabularia spp., which first appeared in the American province in PZ P5b (Gold et al., 2018), appears in Tethys (Plate 6, fig. 10) in the PZ P6b (Drobne, 1985(Drobne, , 1988Drobne and Ćosović, 2009). ...
The superfamily Alveolinoidea is a member of the Order Miliolida, and is comprised of three main families, the Alveolinidae, the Fabulariidae and the Rhapydioninidae. They are examples of Larger Benthic Foraminifera (LBF), which are single cell organisms with specific characteristic endoskeletons. Alveolinoids are found globally from the Cretaceous to present day and are very important biostratigraphic index fossils in shallow-marine carbonates. They are often associated with significant hydrocarbon reservoirs, and exhibit provincialism with characteristic genera often confined to one of the American, Tethyan or Indo-Pacific provinces. Previously, the systematic study of the global interrelationship between the various alveolinoid lineages has not been possible because of the absence of biostratigraphic correlation between the geographically scattered assemblages, and the scarcity of described material from the Indo-Pacific province. Here we use the literature and new material from the Americas, the French Alps, Iran, Tibet, India and SE Asia, coupled with the use the planktonic foraminiferal zonal (PZ) correlation scheme to put forward, for the very first time, a comprehensive, global, systematic analysis of the biostratigraphic, phylogenetic and palaeogeographic evolution of the alveolinoids. The alveolinoids originated in the Cretaceous in the Tethyan province. During a global sea-level low-stand, a westward migration of some alveolinoids species to the Americas occurred in this period, a behaviour also seen in previous studies of contemporaneous orbitolinid LBF. After the K-P event, which saw the extinction of all Cretaceous alveolinoids, rare new forms of alveolinoids evolved again, first in the Americas and later independently in Tethys. As found in previous studies of rotalid LBF, sea-level low-stands in the Paleocene also allowed some alveolinoid forms to migrate, but this time in an eastward direction from the Americas to Tethys, and from Tethys on to the Indo-Pacific. Alveolinoids still exist today ( Borelis and Alveolinella ), the former of which is cosmopolitan, while the latter is restricted to the Indo-Pacific province. Throughout their phylogenetic history alveolinoids characteristically exhibit convergent evolution, with the repeated re-occurrence of certain morphological features. Understanding this propensity to homoplasy is essential in understanding and constructing the phylogenetic relationships within the alveolinoid superfamily.
... The fabulariids were represented in the American province by endemic species, such as F. vaughani Cole, F. cassis, F. colei and F. verseyi. These species are only found in the Caribbean region (Drobne and Ćosović, 2009;Powell, 2010;Gold et al., 2018) from the Early to Middle Eocene (PZ P6 -P12a). In the Middle Eocene, Lutetian (PZ P10) the biloculine Fabularia (Fig. 7) gave rise to Pseudofabularia (Plate 3, fig. ...
... In the Paleocene Periloculina and Pseudolacazina echoed the Cretaceous forms, but they uniquely gave rise to Paleogene Lacazina and Lacazinella by gradual ontogenetic transformation from pluri-to unilocular, completely overlapping growth. The two chambers per whorl is a key-characteristic of the megalospheric forms in the fabulariid, however, in The re-evolved Lacazina is first recorded in Tethys from the Selandian (PZ P4a), while Lacazinella, having completely overlapping chambers, is rare in the Tethyan province and has not been found in Europe, but is only recorded from Oman and other parts of the Middle East On the other hand, the American Fabularia sp., which first appeared in the American province in PZ P5b (Gold et al. 2018), appears in Tethys (Plate 6, fig. 10) in the PZ P6b (Drobne, 1985(Drobne, , 1988Drobne and Ćosović, 2009). ...
The superfamily Alveolinoidea is a member of the Order Miliolida, and is comprised of three main families, the Alveolinidae, the Fabulariidae and the Rhapydioninidae. They are examples of Larger Benthic Foraminifera (LBF), which are single cell organisms with specific characteristic endoskeletons. Alveolinoids are found globally from the Cretaceous to present day and are very important biostratigraphic index fossils in shallow-marine carbonates. They are often associated with significant hydrocarbon reservoirs, and exhibit provincialism with characteristic genera often confined to one of the American, Tethyan or Indo-Pacific provinces. Previously, the systematic study of the global interrelationship between the various alveolinoid lineages has not been possible because of the absence of biostratigraphic correlation between the geographically scattered assemblages, and the scarcity of described material from the Indo-Pacific province. Here we use the literature and new material from the Americas, the French Alps, Iran, Tibet, India and SE Asia, coupled with the use the planktonic foraminiferal zonal (PZ) correlation scheme to put forward, for the very first time, a comprehensive, global, systematic analysis of the biostratigraphic, phylogenetic and palaeogeographic evolution of the alveolinoids. The alveolinoids originated in the Cretaceous in the Tethyan province. During a global sea-level low-stand, a westward migration of some alveolinoids species to the Americas occurred in this period, a behaviour also seen in previous studies of contemporaneous orbitolinid LBF. After the K-P event, which saw the extinction of all Cretaceous alveolinoids, rare new forms of alveolinoids evolved again, first in the Americas and later independently in Tethys. As found in previous studies of rotalid LBF, sea-level low-stands in the Paleocene also allowed some alveolinoid forms to migrate, but this time in an eastward direction from the Americas to Tethys, and from Tethys on to the Indo-Pacific. Alveolinoids still exist today ( Borelis and Alveolinella ), the former of which is cosmopolitan, while the latter is restricted to the Indo-Pacific province. Throughout their phylogenetic history alveolinoids characteristically exhibit convergent evolution, with the repeated re-occurrence of certain morphological features. Understanding this propensity to homoplasy is essential in understanding and constructing the phylogenetic relationships within the alveolinoid superfamily.
... The fabulariids were represented in the American province by endemic species, such as F. vaughani Cole, F. cassis, F. colei and F. verseyi. These species are only found in the Caribbean region (Drobne and Ćosović, 2009;Powell, 2010;Gold et al., 2018) from the Early to Middle Eocene (PZ P6 -P12a). In the Middle Eocene, Lutetian (PZ P10) the biloculine Fabularia (Fig. 7) gave rise to Pseudofabularia (Plate 3, fig. ...
... In the Paleocene Periloculina and Pseudolacazina echoed the Cretaceous forms, but they uniquely gave rise to Paleogene Lacazina and Lacazinella by gradual ontogenetic transformation from pluri-to unilocular, completely overlapping growth. The two chambers per whorl is a key-characteristic of the megalospheric forms in the fabulariid, however, in The re-evolved Lacazina is first recorded in Tethys from the Selandian (PZ P4a), while Lacazinella, having completely overlapping chambers, is rare in the Tethyan province and has not been found in Europe, but is only recorded from Oman and other parts of the Middle East On the other hand, the American Fabularia sp., which first appeared in the American province in PZ P5b (Gold et al. 2018), appears in Tethys (Plate 6, fig. 10) in the PZ P6b (Drobne, 1985(Drobne, , 1988Drobne and Ćosović, 2009). ...
The superfamily Alveolinoidea is a member of the Order Miliolida, and is comprised of three main families, the Alveolinidae, the Fabulariidae and the Rhapydioninidae. They are examples of Larger Benthic Foraminifera (LBF), which are single cell organisms with specific characteristic endoskeletons. Alveolinoids are found globally from the Cretaceous to present day and are very important biostratigraphic index fossils in shallow-marine carbonates. They are often associated with significant hydrocarbon reservoirs, and exhibit provincialism with characteristic genera often confined to one of the American, Tethyan or Indo-Pacific provinces. Previously, the systematic study of the global interrelationship between the various alveolinoid lineages has not been possible because of the absence of biostratigraphic correlation between the geographically scattered assemblages, and the scarcity of described material from the Indo-Pacific province. Here we use the literature and new material from the Americas, the French Alps, Iran, Tibet, India and SE Asia, coupled with the use the planktonic foraminiferal zonal (PZ) correlation scheme to put forward, for the very first time, a comprehensive, global, systematic analysis of the biostratigraphic, phylogenetic and palaeogeographic evolution of the alveolinoids. The alveolinoids originated in the Cretaceous in the Tethyan province. During a global sea-level low-stand, a westward migration of some alveolinoids species to the Americas occurred in this period, a behaviour also seen in previous studies of contemporaneous orbitolinid LBF. After the K-P event, which saw the extinction of all Cretaceous alveolinoids, rare new forms of alveolinoids evolved again, first in the Americas and later independently in Tethys. As found in previous studies of rotalid LBF, sea-level low-stands in the Paleocene also allowed some alveolinoid forms to migrate, but this time in an eastward direction from the Americas to Tethys, and from Tethys on to the Indo-Pacific. Alveolinoids still exist today ( Borelis and Alveolinella ), the former of which is cosmopolitan, while the latter is restricted to the Indo-Pacific province. Throughout their phylogenetic history alveolinoids characteristically exhibit convergent evolution, with the repeated re-occurrence of certain morphological features. Understanding this propensity to homoplasy is essential in understanding and constructing the phylogenetic relationships within the alveolinoid superfamily.
... Present day faunal assemblages, and the mode of life and morphology of organisms, can be used to determine the depositional environment of ancient rocks that contain comparable fossils. Spores, pollen, algae, diatoms, testate amoebae, nannofossils, radiolaria and foraminifera are among the organisms that have been used successfully to reconstruct past sea-level change (e.g., Barlow et al., 2014;Saher et al., 2015;Gold et al., 2017aGold et al., , 2018. Foraminifera are not only useful in oxygen isotope analyses, they can also be used as a proxy for cool-or warm-water conditions and as direct depth indicators to constrain paleobathymetry in marine sediments. ...
... Many studies use the modern and ancient depth distribution of foraminiferal taxa as potential sea-level or water depth indicators (e.g., Hallock and Glenn, 1986; Leckie and Olson, 2003;Hohenegger, 2005;Gold et al., 2017aGold et al., , 2018Goeting et al., 2018). The morphology of many different types of foraminifera can be used to determine water depth, hydrodynamic energy and substrate type. ...
Earth history is defined by a series of greenhouse and icehouse periods associated with cycles of sea-level rise and fall. Throughout time great oceans such as the Tethys have opened and closed and have seen the beginning of life on Earth. Sea-level variation is driven by a variety of factors including orbital (Milankovitch) cyclicity and the Wilson cycle of the formation and break-up of continents which controls the volume of ocean basins. The volume of water in the oceans is also strongly controlled by the volume of water locked up in ice sheets and glaciers, and is therefore linked to changes in mean global temperatures. Consequently, eustatic sea-level rise and fall occurs synchronously with the retreat and expansion of ice sheets, respectively. Interpretations of sea-level change in geological time have traditionally been made using sequence stratigraphic concepts. However, increasing recognition of the non-uniqueness of sedimentary deposits, particularly through the use of numerical forward models, is challenging this approach. Instead, unequivocal evidence for changes in paleobathymetry must be identified to interpret ancient sea-level change in the rock record. This evidence may come from sea temperature studies using oxygen isotopes as a proxy for sea-level change or from direct evidence for bathymetric change from fossil assemblages that are unique to particular depositional settings. Understanding sea-level change in geological time has applications to modern day climate change research and enables scientists to anticipate the likely response of marine ecosystems to global warming and associated sea-level rise.
... In some cases, data from recent studies require important revisions to formerly proposed ages. For example, a 2018 assessment of the Yellow Limestone Group in Jamaica (Gold et al., 2018)-which draws from multiple lines of evidence-found that the Stettin "member" is early-to-middle Lutetian and not terminal Ypresian as previously reported (Savage, Domning & Thewissen, 1994). The implications of this revision are that Prorastomus sirenoides is probably not the earliest known sea cow taxon and that the oldest fossil evidence of Sirenia is more likely from North Africa than the Caribbean. ...
Molecular phylogenetic studies that have included sirenians from the genera Trichechus, Dugong, and Hydrodamalis have resolved their interrelationships but have yielded divergence age estimates that are problematically discordant. The ages of these lineage splits have profound implications for how to interpret the sirenian fossil record — including clade membership, biogeographic patterns, and correlations with Earth history events. In an effort to address these issues, here we present a total evidence phylogenetic analysis of Sirenia that includes living and fossil species and applies Bayesian tip-dating methods to estimate their interrelationships and divergence times. In addition to extant sirenians, our dataset includes 56 fossil species from 106 dated localities and numerous afrotherian outgroup taxa. Genetic, morphological, temporal, and biogeographic data are assessed simultaneously to bring all available evidence to bear on sirenian phylogeny. The resulting time-tree is then used for Bayesian geocoordinates reconstruction analysis, which models ancestral geographic areas at splits throughout the phylogeny, thereby allowing us to infer the direction and timing of dispersals. Our results suggest that Pan-Sirenia arose in North Africa during the latest Paleocene and that the Eocene evolution of stem sirenians was primarily situated in the Tethyan realm. In the late Eocene, some lineages moved into more northern European latitudes, an area that became the source region for a key trans-Atlantic dispersal towards the Caribbean and northern-adjacent west Atlantic. This event led to the phylogenetic and biogeographic founding of crown Sirenia with the Dugongidae-Trichechidae split occurring at the Eocene-Oligocene boundary (~33.9 Ma), temporally coincident with the onset of dropping global sea levels and temperatures. This region became the nexus of sirenian diversification and supported taxonomically-rich dugongid communities until the earliest Pliocene. The Dugonginae-Hydrodamalinae split occurred near Florida during the early Miocene (~21.2 Ma) and was followed by a west-bound dispersal that gave rise to the Pacific hydrodamalines. The late middle Miocene (~12.2 Ma) split of Dugong from all other dugongines also occurred near Florida and our analyses suggest that the Indo-Pacific distribution of modern dugongs is the result of a trans-Pacific dispersal. From at least the early Miocene, trichechid evolution was based entirely in South America, presumably within the Pebas Wetlands System. We infer that the eventual establishment of Amazon drainage into the South Atlantic allowed the dispersal of Trichechus out of South America no earlier than the mid-Pliocene. Our analyses provide a new temporal and biogeographic framework for understanding major events in sirenian evolution and their possible relationships to oceanographic and climatic changes. These hypotheses can be further tested with the recovery and integration of new fossil evidence.
PeerJ 10:e13886 http://dx.doi.org/10.7717/peerj.13886
... Divergence estimates to the Cretaceous (~ 75 Mya) 22 was also proposed (Table 1; STables 5-6). During this time, however, the Yucatán platform was predominantly submerged, although global sea-level oscillations led to periods of partial submergence and emergence [52][53][54]62,67,68 . The formation of and position of the Paleogene Arc in proximity to Middle America did not occur until the late Cretaceous and early Paleocene 59 , respectively. ...
The Yucatán Peninsula, Mexico is a carbonate platform well-known for extensive karst networks of densely stratified aquifer ecosystems. This aquifer supports diverse anchialine fauna, including species of the globally distributed anchialine shrimp genus Typhlatya (Atyidae). Four species (T. campecheae, T. pearsei, T. dzilamensis and T. mitchelli) are endemic to the Peninsula, of which three are federally listed in Mexico. This first integrative evaluation (i.e., molecular, morphological, broad geographic and type locality sampling, and environmental data) of Yucatán Typhlatya reveals considerable species identity conflict in prior phylogenetic assessments, broad species ranges, syntopy within cave systems and five genetic lineages (of which two are new to science). Despite sampling from the type locality of endangered T. campecheae, specimens (and molecular data) were indistinguishable from vulnerable T. pearsei. Ancestral/divergence reconstructions support convergent evolution of a low-salinity ancestor for a post-Paleogene arc Yucatán + Cuba Typhlatya clade within the anchialine Atyidae clade. A secondary adaptation for the coastal-restricted euryhaline (2–37 psu), Typhlatya dzilamensis (unknown conservation status) was identified, while remaining species lineages were low-salinity (< 5 psu) adapted and found within the meteoric lens of inland and coastal caves. This study demonstrates the need for integrative/interdisciplinary approaches when conducting biodiversity assessments in complex and poorly studied aquifers.
In biogeography, vicariance and long-distance dispersal are often characterised as competing scenarios. However, they are related concepts, both relying on collective geological, ecological, and phylogenetic evidence. This is illustrated by freshwater fishes, which may immigrate to islands either when freshwater connections are temporarily present and later severed (vicariance), or by unusual means when ocean gaps are crossed (long-distance dispersal). Marine barriers have a strong filtering effect on freshwater fishes, limiting immigrants to those most capable of oceanic dispersal. The roles of vicariance and dispersal are debated for freshwater fishes of the Greater Antilles. We review three active hypotheses [Cretaceous vicariance, Greater Antilles-Aves Ridge (GAARlandia), long-distance dispersal] and propose long-distance dispersal to be an appropriate model due to limited support for freshwater fish use of landspans. Greater Antillean freshwater fishes have six potential source bioregions (defined from faunal similarity): Northern Gulf of México, Western Gulf of México, Maya Terrane, Chortís Block, Eastern Panam a, and Northern South America. Faunas of the Greater Antilles are composed of taxa immigrating from many of these bioregions, but there is strong compositional disharmony between island and mainland fish faunas (>90% of Antillean species are cyprinodontiforms, compared to <10% in Northern Gulf of México and Northern South America, and ≤50% elsewhere), consistent with a hypothesis of long-distance dispersal. Ancestral-area reconstruction analysis indicates there were 16 or 17 immigration events over the last 51 million years, 14 or 15 of these by cyprinodontiforms. Published divergence estimates and evidence available for each immigration event suggests they occurred at different times and by different pathways, possibly with rafts of vegetation discharged from rivers or washed to sea during storms. If so, ocean currents likely provide critical pathways for immigration when flowing from one landmass to another. On the other hand, currents create dispersal barriers when flowing perpendicularly between landmasses. In addition to high salinity tolerance, cyprinodontiforms collectively display a variety of adaptations that could enhance their ability to live with rafts (small body size, viviparity, low metabolism, amphibiousness, diapause, self-fertilisation). These adaptations likely also helped immigrants establish island populations after arrival and to persist long term thereafter. Cichlids may have used a pseudo bridge (Nicaragua Rise) to reach the Greater Antil-les. Gars (Lepisosteidae) may have crossed the Straits of Florida to Cuba, a relatively short crossing that is not a barrier to gene flow for several cyprinodontiform immigrants. Indeed, widespread distributions of Quaternary migrants (Cyprinodon, Gambusia, Kryptolebias), within the Greater Antilles and among neighbouring bioregions, imply that long-distance dispersal is not necessarily inhibitory for well-adapted species, even though it appears to be virtually impossible for all other freshwater fishes.
Kumar A. 2023. Palynological research in the Caribbean Islands and Central America: An overview. Geophytology 53(1): 83-98.
There is rich literature on palynological research in the Caribbean Islands and the adjoining regions of Central America. However, these papers were published in a variety of diverse journals originating from several countries mainly in the Americas, Europe, and a few from the Caribbean countries as well. An overview of the palynological research in the Caribbean and the adjoining regions provides information on the diverse application of palynology in the Earth and Environmental Sciences. This study also provides a survey of significant papers useful to researchers in this field of science interested in initiating a research project in this region. However, some aspects of palynology such as Melissopalynology (study of pollen and spores in honey), Forensic Palynology (study of palynomorphs in Criminology), Entomopalynology (pollen studies in the body of insects) and study of pollen allergens have not yet been addressed in this region.
Echinoids are key components of modern marine ecosystems. Despite a remarkable fossil record, the emergence of their crown group is documented by few specimens of unclear affinities, rendering their early history uncertain. The origin of sand dollars, one of its most distinctive clades, is also unclear due to an unstable phylogenetic context. We employ 18 novel genomes and transcriptomes to build a phylogenomic dataset with a near-complete sampling of major lineages. With it, we revise the phylogeny and divergence times of echinoids, and place their history within the broader context of echinoderm evolution. We also introduce the concept of a chronospace – a multidimensional representation of node ages – and use it to explore methodological decisions involved in time calibrating phylogenies. We find the choice of clock model to have the strongest impact on divergence times, while the use of site-heterogeneous models and alternative node prior distributions show minimal effects. The choice of loci has an intermediate impact, affecting mostly deep Paleozoic nodes, for which clock-like genes recover dates more congruent with fossil evidence. Our results reveal that crown group echinoids originated in the Permian and diversified rapidly in the Triassic, despite the relative lack of fossil evidence for this early diversification. We also clarify the relationships between sand dollars and their close relatives and confidently date their origins to the Cretaceous, implying ghost ranges spanning approximately 50 million years, a remarkable discrepancy with their rich fossil record.
Echinoids are key components of modern marine ecosystems. Despite a remarkable fossil record, the emergence of their crown group is documented by few specimens of unclear affinities, rendering their early history uncertain. The origin of sand dollars, one of its most distinctive clades, is also unclear due to an unstable phylogenetic context. We employ seventeen novel genomes and transcriptomes to build a dataset with a near-complete sampling of major lineages and use it to revise the phylogeny and divergence times of echinoids. We introduce the concept of a chronospace—a multidimensional representation of node ages—and use it to explore the effects of using alternative gene samples, models of molecular evolution, and clock priors. We find the choice of clock model to have the strongest impact on divergence times, while gene sampling and the use of site-heterogeneous models show little effects. Crown group echinoids originated in the Permian and diversified rapidly in the Triassic. We clarify the relationships among sand dollars and their close relatives, showing that Apatopygus represents a relict lineage with a deep Jurassic origin. Sand dollars are confidently dated to the Cretaceous, implying ghost ranges spanning approximately 50 million years, a remarkable discrepancy with their fossil record.
The superfamily Alveolinoidea is a member of the Order Miliolida, and comprises three
main families, the Alveolinidae, the Fabulariidae and the Rhapydioninidae. They are
examples of Larger benthic foraminifera (LBF), which are single-celled organisms with
specific characteristic endoskeletons. Alveolinoids are found globally from the Cretaceous
to the present day, and are important biostratigraphic index fossils in shallow-marine
carbonates. They are often associated with hydrocarbon reservoirs, and exhibit provincialism
with characteristic genera often confined to one of the American, Tethyan or Indo-Pacific
provinces. Previously, the systematic study of the global interrelationship between
the various alveolinoid lineages has not been possible because of the absence of biostratigraphic
correlation between the geographically scattered assemblages, and the scarcity of
described material from the Indo-Pacific province. Here we use the literature and
new material from the Americas, the French Alps, Iran, Tibet, India and South East
Asia, coupled with the use of the planktonic foraminiferal zonal (PZ) correlation
scheme to propose a comprehensive, global, systematic analysis of the biostratigraphic,
phylogenetic and paleogeographic evolution of the alveolinoids. The alveolinoids originated
in the Cretaceous in the Tethyan province. During a global sea-level low stand, a
westward migration of some alveolinoids species to the Americas occurred, a behaviour
previously reported in contemporaneous orbitolinid LBF. After the Cretaceous/Palaeogene
(K–P) event, which saw the extinction of all Cretaceous alveolinoids, rare new forms
of alveolinoids evolved again, first in the Americas and later independently in Tethys.
As was found in previous studies of rotalid LBF, sea-level low stands in the Paleocene
also allowed some alveolinoid forms to migrate, but this time in an eastward direction
from the Americas to Tethys, and from Tethys on to the Indo-Pacific province. Alveolinoids
still exist today (
Borelis and
Alveolinella), the former of which is cosmopolitan, while the latter is restricted to the Indo-Pacific
province. Throughout their phylogenetic history, alveolinoids characteristically exhibit
convergent evolution, with the repeated re-occurrence of certain morphological features.
Understanding this propensity to homoplasy is essential in understanding and constructing
the phylogenetic relationships within the alveolinoid superfamily.
The island of Jamaica forms the northern extent of the Nicaraguan Rise, an elongate linear tectonic feature stretching as far as Honduras and Nicaragua to the south. Uplift and subaerial exposure of Jamaica during the Neogene has made the island rare within the Caribbean region, as it is the only area where rocks of the Nicaraguan Rise are exposed on land. Biostratigraphic dating and palaeoenvironmental interpretations using larger benthic foraminifera, supplemented by planktonic foraminifera, nannopalaeontology and palynology of outcrop, well and corehole samples has enabled the creation of a regional relative sea-level curve through identification of several depositional sequences. This study recognises ten unconformity-bounded transgressive-regressive sequences which record a complete cycle of relative sea level rise and fall. Sequences are recognised in the Early to ‘Middle’ Cretaceous (EKTR1), Coniacian-Santonian (STR1), Campanian (CTR1), Maastrichtian (MTR1-2), Paleocene-Early Eocene (PETR1), Eocene (YTR1-3) and Late Eocene-Oligocene (WTR1). These transgressive-regressive cycles represent second to fourth order sequences, although most tie with globally recognised third order sequences. Comparisons of the Jamaican relative sea-level curve with other published global mean sea-level curves show that local tectonics exerts a strong control on the deposition of sedimentary sequences in Jamaica. Large unconformities (duration >1 Ma) are related to significant regional tectonic events, with minor overprint of a global eustatic signal, while smaller unconformities (duration <1 Ma) are produced by global eustatic trends. The relatively low rates of relative sea-level rise calculated from the regional relative sea-level curve indicate that carbonate production rates were able to keep pace with the rate of relative sea-level rise accounting for the thick successions of Maastrichtian carbonates and those of the Yellow and White Limestone Groups. Carbonate platform drowning within the White Limestone Group during the Oligocene to Miocene is attributed to environmental deterioration given the low rates of relative sea-level rise.
We present new biostratigraphic analyses of approximately 200 outcrop samples and review biostratigraphic data from 136 public domain exploration wells across western New Guinea. Biostratigraphic ages and palaeodepositional environments were interpreted from occurrences of planktonic and larger benthic foraminifera, together with other fossils and environmental indicators where possible. These data were compared with existing geological maps and exploration well data to reconstruct the palaeogeography of western New Guinea from the Carboniferous to present day. In addition, we used the known bathyal preferences of fossils to generate a regional sea-level curve and compared this with global records of sea-level change over the same period. Our analyses of the biostratigraphic data identified two major transgressive-regressive cycles in regional relative sea-level, with the highest sea levels recorded during the Late Cretaceous and Late Miocene and terrestrial deposition prevalent across much of western New Guinea during the Late Paleozoic and Early Mesozoic. An increase in the abundance of carinate planktonic foraminifera indicates a subsequent phase of relative sea-level rise during a regional transgressive event between the Late Jurassic and Late Cretaceous. However, sea-levels dropped once more during a regressive event between the Late Cretaceous and the Paleogene. This resulted in widespread shallow water carbonate platform development in the Middle to Late Eocene. A minor transgressive event occurred during the Oligocene, but this ceased in the Early Miocene, likely due to the collision of the Australian continent with intra-Pacific island arcs. This Miocene collision event resulted in widespread uplift that is marked by a regional unconformity. Carbonate deposition continued in platforms that developed in shallow marine settings until these were drowned during another transgressive event in the Middle Miocene. This transgression reached its peak in the Late Miocene and was followed by a further regression culminating in the present day topographic expression of western New Guinea.
The geology of the Jerusalem Mountain Inlier is revised based on geological mapping. Five Cretaceous formations are recognized: Mint Formation (new name); Thicket River Formation; Belleisle Formation (new name); Jerusalem Formation; Masemure Formation. The Mint Formation is introduced for what has previously been called the Moreland Formation. Descriptions of the formations and locations of the type sections are indicated. In terms of structure, the inlier shows only gentle folding and does not represent an anticline as previously interpreted.
The forms A, B and C are described and tentative comparison with existing genera made. This gyrogonite assemblage suggests a Maestrichtian age for the upper part of Slippery Rock Formation and confirms that these sediments were deposited in a marginal marine environment. Charophytes are an important group of fossils, both biostratigraphically and palaeoecologically.-from Authors
Northern Honduras and its offshore area include an active transtensional margin separating the Caribbean and North American plates. We use deep-penetration seismic-reflection lines combined with gravity and magnetic data to describe two distinct structural domains in the Honduran offshore area: (1) an approximately 120 km-wide Honduran Borderlands (HB) adjacent to the Cayman Trough characterized by narrow rift basins controlled by basement-involving normal faults subparallel to the margin; and (2) the Nicaraguan Rise (NR), characterized by small-displacement normal faulting and sag-type basins influenced by Paleocene–Eocene shelf sedimentation beneath an Oligocene–Recent, approximately 1–2 km-thick carbonate platform. Thinning of continental crust from 25–30 km beneath the NR to 6–8 km beneath the oceanic Cayman Trough is attributed to an Oligocene–Recent phase of transtension. Five tectonostratigraphic phases established in the HB and NR include: (1) a Late Cretaceous uplift in the north and south-dipping thrusting related to the collision in the south, between the Chortis continental block and arc and oceanic plateau rocks of the Caribbean; (2) Eocene sag basins in the NR and minor extension in the HB; two phases (3) and (4) of accelerated extension (transtension) across the subsidence mainly of the HB; and (5) Pliocene–Recent minor fault activity in the HB and a stable carbonate platform in the NR.
During the early Maastrichtian an assemblage rich in large foraminifera, mostly composed of orbitoidal foraminifera, developed in the shallow-water deposits of the Cárdenas Formation (Valles-San Luis Potosí Platform, Mexico). Among them, the most abundant is Lepidorbitoides minima, some of which display a morphologically abnormal test consisting of polyvalent forms, conical tests and budding, which could be induced by abrupt changes in environmental factors. The occurrence of the abnormalities preceded the demise of this species and of all the larger foraminiferal association in the upper part of the Gansserina gansseri Zone (early Maastrichtian). The abnormalities could be induced by environmental stress, probably related to interplay of different events such as increased terrigenous input and the transition to deeper facies due to Laramide tectonic instability before the K/P boundary. A late Maastrichtian community of dwarfed planktic foraminifera composed of Trinitella scotti Brönnimann, Plummerita reicheli Brönnimann, Rugoglobigerina cf. macrocephala Brönnimann, Rugoglobigerina hexacamerata Brönnimann, Heterohelix punctulata (Cushman), Pseudoguembelina costulata (Cushman), Pseudotextularia intermedia de Klasz, Globigerinelloides asperus Bolli, Guembelitria cretacea Cushman, Rugoglobigerina rugosa (Plummer), Rugotruncana sp., Globotruncanita stuarti (de Lapparent), and Globotruncana arca (Cushman) developed in the upper part of the sequence. This uncommon morphology could also be related to the highly stressed paleoenvironmental conditions related to global climatic change and local tectonic activity. Associated with this planktic assemblage is a deeper-water dwarfed benthic foraminiferal community composed of Gyroidinoides nitidus (Reuss), Coryphostoma incrassata (Reuss), Pseudouvigerina plummerae Cushman, P. cretacea Cushman, Bolivina cretosa Cushman, Planulina texana Cushman and Cibicides harperi (Sandidge).
This is an important and authoritative review of foraminiferal ecology, the first for over a decade. Professor Murray relates ecological data on living forms of foraminifera to the palaeoecology of fossil species, and defines in detail areas of global distribution.
The effect of rapid erosion on kinematic partitioning along transpressional plate margins is not well understood, particularly in highly erosive climates. The Blue Mountains restraining bend (BMRB) of eastern Jamaica, bound to the south by the left-lateral Enriquillo-Plantain Garden fault (EPGF), offers an opportunity to test the effects of highly erosive climatic conditions on a 30-km-wide restraining bend system. No previous thermochronometric data exists in Jamaica to describe the spatial or temporal pattern of rock uplift and how oblique (> 20°) plate motion is partitioned into vertical strain. To define the exhumation history, we measured apatite (n = 10) and zircon (n = 6) (U-Th)/He ages, ⁴⁰Ar/³⁹Ar (n = 2; amphibole and K-spar) ages, and U/Pb zircon (n = 2) crystallization ages. Late Cretaceous U/Pb and ⁴⁰Ar/³⁹Ar ages (74–68 Ma) indicate rapid cooling following shallow emplacement of plutons during north-south subduction along the Great Caribbean Arc. Early to middle Miocene zircon helium ages (19–14 Ma) along a vertical transect suggest exhumation and island emergence at ~ 0.2 mm/yr. Older zircon ages 10–15 km to the north (44–35 Ma) imply less rock uplift. Apatite helium ages are young (6–1 Ma) across the entire orogen, suggesting rapid exhumation of the BMRB since the late Miocene. These constraints are consistent with previous reports of restraining bend formation and early emergence of eastern Jamaica. An age-elevation relationship from a vertical transect implies an exhumation rate of 0.8 mm/yr, while calculated closure depths and thermal modeling suggests exhumation as rapid as 2 mm/yr. The rapid rock uplift rates in Jamaica are comparable to the most intense transpressive zones worldwide, despite the relatively slow (5–7 mm/yr) strike-slip rate. We hypothesize highly erosive conditions in Jamaica enable a higher fraction of plate motion to be accommodated by vertical deformation. Thus, strike-slip restraining bends may evolve differently depending on erosivity and local climate.
The role of fossil planktonic foraminifera as markers for biostratigraphical zonation and correlation underpins most drilling of marine sedimentary sequences and is key to hydrocarbon exploration. Biostratigraphic and Geological Significance of Planktonic Foraminifera unifies existing biostratigraphic schemes and provides an improved correlation reflecting regional biogeographies. It presents a comprehensive analysis of existing data on fossil planktonic foraminifera genera and their phylogenetic evolution in time and space. Coverage includes presentation and discussion of rarely studied thin sections of planktonic foraminifera, allowing for new developments in dating planktonic foraminifera in carbonates and expanding their usefulness in hydrocarbon exploration.
The late Palaeozoic buried Finnmark platform, in the Norwegian Barents Sea, is a depositional system which developed under major modifications of palaeoclimatic and palaeoceanographic conditions, given by the northward drifting of the Arctic depositional domain beyond the tropical belt, the activity of the Gondwanan icecaps, and the gradual closure of the Eastern European seaway. In this study, detailed core/microfacies analysis from the explorations wells 7128/4-1 and 7128/6-1, combined with new 2D seismic sections and available dataset from previous studies in the eastern Finnmark area, have allowed a re-evaluation of the depositional scenarios associated with the Ørn and Isbjørn/Polarrev Formations. The late Asselian–early Sakmarian depositional record of the Ørn Formation, followed by the middle Sakmarian transition to the Isbjørn/Polarrev Formations, shows depth-related variations in sedimentation modes and a change of the platform morphology.
The Wagwater Trough is a fault-bounded basin which cuts across east-central Jamaica. The basin formed during the late Palaeocene or early Eocene and the earliest sediments deposited in the trough were the Wagwater and Richmond formations of the Wagwater Group. These formations are composed of up to 7000 m of conglomerates, sandstones, and shales. Six facies have been recognized in the Wagwater Group: Facies I-unfossiliferous massive conglomerates; Facies II-channelized, non-marine conglomerates, sandstones, and shales; Facies III-interbedded, fossiliferous conglomerates and sandstones; Facies IV-fossiliferous muddy conglomerates; Facies V-channelized, marine conglomerates, sandstones, and shales; and Facies VI-thin-bedded sheet sandstones and shales. The Wagwater and Richmond formations are interpreted as fan delta-submarine fan deposits. Facies associations suggest that humid-region fan deltas prograded into the basin from the adjacent highlands and discharged very coarse sediments on to a steep submarine slope. At the coast waves reworked the braided-fluvial deposits of the subaerial fan delta into coarse sand and gravel beaches. Sediments deposited on the delta-front slope were frequently remobilized and moved downslope as slumps, debris flows, and turbidity currents. At the slope-basin break submarine fans were deposited. The submarine fans are characterized by coarse inner and mid-fan deposits which grade laterally into thin bedded turbidites of the outer fan and basin floor.
Topographic features of submerged oceanic areas have received less attention from geographers than have inhabited islands or economically important fishing banks, with the result that geographic names are slow to become established and some areas may have several designations. This has been the case in the western Caribbean where the suboceanic ridge extending eastward from Central America to Jamaica and beyond—the Nicaragua Rise—is called by different names on recently published maps. Current practice seems to favor the direct use of a nearby land name for the oceanic feature without an adjective modification. Examples are Colombia Basin, Barbados Ridge, Grenada Trough, and Puerto Rico Trench. Where a name has not already become firmly established, this practice will be followed here.
Thickness and sedimentation rates of time-stratigraphic units deposited during deltaic progradation can be predicted from a mathematical model. Depositional surfaces are constrained to lie along an assumed equilibrium bathymetric profile that advances seaward at a specified rate. Subsidence is treated as an isostatic response and so is related to the weight of accumulated sediment. Effects of contemporaneous compaction are included to obtain correct weights and thicknesses of stratigraphic units.
Carbonate rocks (limestones and dolomites) constitute a major part of the geological column and contain not only 60% of the world's known hydrocarbons but also host extensive mineral deposits. This book represents the first major review of carbonate sedimentology since the mid 1970's. It is aimed at the advanced undergraduate - postgraduate level and will also be of major interest to geologists working in the oil industry. Carbonate Sedimentology is designed to take the reader from the basic aspects of limestone recognition and classification through to an appreciation of the most recent developments such as large scale facies modelling and isotope geochemistry. Novel aspects of the book include a detailed review of carbonate mineralogy, non-marine carbonate depositional environments and an in-depth look at carbonate deposition and diagenesis through geologic time. In addition, the reviews of individual depositional systems stress a process-based approach rather than one centered on simple comparative sedimentology. The unique quality of this book is that it contains integrated reviews of carbonate sedimentology and diagenesis, within one volume.
Cretaceous orbitoid larger foraminifera of the families Pseudorbitoididae, Orbitoididae, and Orbitocyclinidae are known from the Green Island and Grange inliers (western Jamaica), from the Sunderland and Central inliers (west-central Jamaica), and from the Blue Mountain Inlier (eastern Jamaica). They occur in prominent limestone units that are regarded as ranging in age from Campanian to Early Maastrichtian on the basis of nannofossils and accompanying rudist assemblages. Cretaceous pseudorbitoid, orbitoid, and orbitocyclinid foraminifera are useful in interpreting fluctuations of the depositional environment and for time-stratigraphic correlation of Late Cretaceous limestones across Jamaica.
This article deals with the most important aspects of nearly twenty years of intensive study of the pollen-and-spore content of Tertiary sediments in some parts of tropical South America, Africa and Asia. For a proper evaluation, the character of the data, including the selection and preparation of the samples, the diversity of previous recording and the statistically achieved uniformity in presentation of these basic data needs a full exposition, given in the introduction. This is directly followed by an explanation of the process of elimination of all stratigraphically unimportant species. The resulting interpretation of climatic and topographical influences on the dispersal of pollen and spores is illustrated with examples from the fossil record. The disturbing effect of redeposition forms a problem, which in some cases can be solved. Now that the main ways of dispersal of pollen and spores are understood, the characteristics of the three major depositional environments can be distinguished by purely statistical analysis, without necessarily having any botanical information from probably related Recent plant species. Additionally botany and palaeontology may bring supporting evidence. This many-sided approach leads to the discrimination between local and regional features of environmental or time-stratigraphical significance which is needed for the evaluation of long-distance correlation. As a result the marker species can be classified into: (1) a restricted number of pantropical marker species; (2) a larger number of marker species which occurred in both the South American and west African regions, tropical today (transatlantic distribution); and (3) a still greater quantity of species which are of significance only within a single botanical province (intracontinental distribution). Thus a broad stratigraphical framework on a pantropical scale is established, which may be further subdivided regionally. These three systems of subzonation are compared with independent zoopalaeontological time-stratigraphical correlation and discussed in great detail, with special emphasis on the Carribean data. The major palynological changes marking the boundaries of the pantropical subzonation are thought to reflect the evolution of new groups of plants. They are mostly marked by a gradual incoming of pollen types. Extinction of plants is stratigraphically of less value, since they may have survived longer in one area than in another. Climatic boundaries are next in importance, but in general they are more restricted to specific regions. Similarly the immigration of plants, although producing sharp and useful boundaries, is only of regional value. Of least significance for regional correlation are the locally restricted boundaries which are caused by changes in habitat or dispersal. They may still be valuable for studies within one basin. An intriguing aspect of the palynological studies is formed by the possible affinity of the fossil type with Recent botanical species. Such affinities are obviously present in many fossil types. Whereas most are restricted to the level of family relationship, some interesting cases of much closer affinity are recorded here. In exceptional cases the morphogenetic development and migration of a restricted group of related pollen types can be traced. In the final section of this paper the species selected for this study have been formally described and illustrated; they include several new ones. The study is further documented by distribution charts and sections showing the stratigraphical significance of the marker types, as discussed in detail in the stratigraphical section.
Thirty-four genera and fifty species and subspecies of Paleogene larger foraminifera from Jamaican localities are reviewed and illustrated. Three species, Athecocyclina stephensoni, Hexagonocyclirta inflata, and Rarukothalia catenula, are from Paleocene localities in eastern Jamaica, described for the first time. Ten species first appear in the early Eocene, sixteen in the early middle Eocene, and nine in the late middle Eocene. Four species are confined to the late Eocene. Six species first appear in the early Oligocene, including such characteristic forms as Lepidocyclina undosa and L. yurnagunensis. The first occurrence of Miogypsinoides spp. is used to define the base of the upper Oligocene, but in the back-reef and lagoonal carbonates of the White Limestone Group the boundary between the lower and upper Oligocene is still poorly defined. Here, peneroplid and related forms, such as Archaias asmaricus, not previously recorded from the Caribbean region, and Praerhapydionina delicata are of local biostratigraphic importance.
Evolution and Geological Significance of Larger Benthic Foraminifera is a comprehensive reference work on the larger benthic foraminifera. This second edition is substantially revised, including extensive reanalysis of the most recent work on Cenozoic forms. It provides documentation of the biostratigraphic ranges and palaeoecological significance of the larger foraminifera, which is essential for understanding many major oil-bearing sedimentary basins. In addition, it offers a palaeogeographic interpretation of the shallow marine late Palaeozoic to Cenozoic world.
The post-Hercynian sequence of the Middle East is dominated by carbonate sedimentation on a stable platform flanked on the NE by the Tethys ocean. Two principal types of depositional systems alternated in time: 1) ramp-type mixed carbonate-clastic units and 2) differentiated carbonate shelves. The tectonic development of the Middle East can be divided into several stages, which affected the stability of this platform. Source rocks were formed in the starved basins during the transgressive periods. Marginal mounds, rudist banks, oolite bars and sheets, and regressive sandstones form the main reservoirs. Supratidal evaporites and regressive shales are the regional seals. The spatial arrangement of these elements and the development of source maturity through time explain the observed distribution of the oil and gas fields. -from Author