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Sampled section of the Dharang Member, Habo Formation, Habo Dome, near Dharang village, Kutch, Gujarat, India.
Source publication
The Middle Jurassic, Dharang Member of the Habo Formation, Habo Dome, Kutch, India yields rich foraminiferal assemblages comprising 59 species. The assemblages are dominated by the families Vaginulinidae and Nodosariidae. This paper is a systematic account of the 22 species recorded for the first time from this region. The foraminiferal assemblages...
Contexts in source publication
Context 1
... was sampled. The present study is confined to the Dharang Member, which is well exposed in the centre of the Habo Dome, about 1.75 km south of the village of Dharang where it overlies the Black Limestone Member. The total thickness of the Dharang Member is about 62 m, which can be subdivided into 10 lithological units designated as D-1 to D-10 ( Fig. ...
Context 2
... micropalaeontological samples were collected on the basis of lithological variation from the nala-cutting section (Fig. 3). The samples were crushed, boiled and treated in either sodium carbonate or sodium hydroxide. The disintegrated material was washed and screened through a set of standard sieves with 30, 60 and 120 mm meshes and dried in an oven. From both the 60 and 120 mm mesh fractions, 10 g of material was picked under a stereo-zoom binocular ...
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Citations
... Several workers have documented many research articles on palaeontological aspects. All these studies had helped in developing the stratigraphic sequence, determination of age, interregional correlation, and estimation of the depositional environment (Rajnath, 1932;Barnard, 1948;Tewari, 1957;Subbotina et al., 1960;Agrawal and Singh, 1961;Singh;1979, Casshyap et al., 1983Govindan et al., 1988;Singh, 1989, 1994;Pandey and Dave, 1993;Sisodia, 2000, Fursich et al., 2004;Talib and Faisal, 2007;Gaur and Talib, 2009, Talib et al., 2016. All these works emphasized the micropalaeontological importance to understanding the biostratigraphy, palaeogeography, and palaeoclimate that prevailed during the Jurassic Period. ...
Total forty-four surficial samples were collected at six locations (J1 to J6) from the Jhurio and Jumara Formations exposed at the Jhurio (Jhura) Dome, Kachchh district of Gujarat. Thirteen major species were considered for the Principal Component Analysis (PCA) out of forty-five identified foraminiferal species. PCA (both factor and cluster analyses) helped us to retain four foraminiferal groups (Sl, Et, Rr, En). The established ecological preferences of each species are used to reconstruct palaeodepositional environment. The basal golden oolitic limestone sequence (locations J5 and J6) is dominated by foraminiferal group Et (Epistomina turgidula, Epistomina nuda), suggesting oxygen-depleted, outer shelf environment depositional environment and Bathonian age for the Jhurio Formation. Foraminiferal group En (Epistomina nuda, Verneuilinoides tryphera, Spirillina polygyrata, Tandonina paula) dominates in the Jumara Formation sediments suggesting low-oxygenated, outer shelf depositional environment similar to the Jhurio Formation. However, intervals with foraminiferal groups Rr (Epistomina nuda, Verneuilinoides tryphera, Spirillina polygyrata, Tandonina paula), and Sl (Saracenaria latifrons) indicate relatively shallower depositional depth (inner shelf) in an oxygen-depleted environment. The established foraminiferal assemblage contains some moderately short-ranging species either restricted to Bathonian or frequently reported from Bathonian to Oxfordian strata indicating Bathonian to Oxfordian age of the Jumara Formation exposed at Jhurio Dome. The foraminiferal group distribution pattern also shows variations in depositional depths (outer shelf to inner shelf and vice versa) during the middle Jurassic indicating sea-level fluctuation.
... The representative genera are Epistomina, Garantella and Conorboides. As such, Epistomina is contemplated to represent the outer shelf environment in the lower sub-tidal region ( Samson, 2001 ;Reolid et al., 2008a ;Talib et al., 2016b ). The genus Epistomina is positively sensitive to fine-grained and muddy seasurfaces ( Le Calvez, 1958 ;Colpaert et al., 2017a ). ...
... In the studied interval, calcareous SG-J2 is dominant (57.89%) which suggests normal oxygen level, dominance of shallow infaunal forms and detritivores bacterial scavengers ( Fig. 5 ) towards normal oxygen in open oceanic deeper shelf environment with normal salinity (35 ‰ ), and comparatively high sedimentation rate and high nutrient availability ( Reolid et al., 2008a( Reolid et al., , b, 2010Reolid and Martínez-Ruiz, 2012 ;Reolid, 2014 ;Reolid et al., 2014 ;Talib et al., 2016b ;Davies, 2016 ;Hjalmarsdottir et al., 2018 ;Farahani et al., 2018 ;Wasim et al., 2021 ). Davies (2016) suggested that high nutrient availability is due to marine transgression which increases primary productivity ( Leckie and Olson, 2003 ;Nagy et al., 2009 ;Davies et al., 2020 ). ...
... ml/l O 2 level ( Olóriz et al., 2006 ;Reolid et al., 2008aReolid et al., , b, 2010Reolid et al., , 2019bBubenshchikova et al., 2010 ;Rita et al., 2016 ;Colpaert et al., 2017b ;Silva et al., 2020 ). The presence of the shallow infaunal group and detritivore bacterial scavengers ( Fig. 5 ) also support stable environmental conditions at the sea floor with normal oxygen levels in a deeper shelf environment ( Reolid et al., 2008aTalib et al., 2016b ;Hjalmarsdottir et al., 2018 ). ...
The analysis of the benthic foraminiferal assemblages recovered from the Jurassic sequence exposed at Jhurio Dome, Kutch, reveals the presence of six types of major morphogroups, some of them subdivided into subgroups. Changes in benthic foraminiferal morphogroups, including life habitat (from epifaunal to deep infaunal) and nutritional behaviour (from herbivores to omnivores, suspension-feeders to bacterial scavengers and detritivores to primary weed fauna) are mainly influenced by fluctuations in nutrient flux, oxygen availability, salinity and bathymetry and are reliable indicators to interpret palaeoenvironmental fluctuations during the deposition of the sediments.
The Middle to Upper Jurassic sequence of Jhurio Dome is subdivided into four palaeoecological intervals on the basis of benthic foraminiferal morphogroup associations. Deposition in Palaeoecological interval I commenced with a transgressive phase in the outer shelf region with normal salinity as well as high oxygen and nutrient availability. Palaeoecological interval II witnessed fluctuating hyposaline conditions, depleted oxygen and low nutrient availability in a regressive episode in the middle shelf environment. Palaeoecological interval III is considered to have been deposited in a transgressive phase in the deepest part of the outer shelf with high salinity, increased levels of oxygen and nutrient flux. Palaeoecological interval IV, representing the upper part of the studied sequence is characterised by normal salinity, decreased oxygen levels, and high nutrient influx in a regressive middle shelf environment. The morphogroup analysis shows that, during the deposition of the analysed stratigraphic intervals, the environmental conditions at the sediment depositional site did not remain stable as indicated by the fluctuating shoreline on a tectonically rather unstable oceanic shelf.
Resumé
L'analyse des assemblages de foraminifères benthiques récupérés de la séquence jurassique affleurant à Jhurio Dome, Kutch révèle la présence de six types de morphogroupes majeurs, certains d'entre eux subdivisés en sous-groupes. Les changements dans les morphogroupes des foraminifères benthiques, y compris l'habitat de vie (de l'épifaune à l'endofaune profonde) et le comportement nutritionnel (des herbivores aux omnivores, des suspensivores aux charognards bactériens et des détritivores à la faune primaire herbivore) sont principalement influencés par les fluctuations du flux de nutriments, la disponibilité en oxygène, la salinité et bathymétrie et sont des indicateurs fiables pour interpréter les fluctuations paléoenvironnementales lors du dépôt des sédiments.
La séquence du Jurassique moyen à supérieur de Jhurio Dome est subdivisée en quatre intervalles paléoécologiques sur la base d'associations de morphogroupes de foraminifères benthiques. Le dépôt dans l'intervalle paléoécologique I a commencé par une phase transgressive dans la région du plateau externe avec une salinité normale ainsi qu'une disponibilité élevée en oxygène et en nutriments. L'intervalle paléoécologique II a été témoin de conditions hyposalines fluctuantes, d'un épuisement de l'oxygène et d'une faible disponibilité des nutriments dans un épisode régressif dans l'environnement du plateau intermédiaire. L'intervalle paléoécologique III est considéré comme ayant été déposé dans une phase transgressive dans la partie la plus profonde du plateau externe avec une salinité élevée, des niveaux accrus d'oxygène et de flux de nutriments. L'intervalle paléoécologique IV, représentant la partie supérieure de la séquence étudiée, est caractérisé par une salinité normale, une diminution des niveaux d'oxygène et un afflux élevé de nutriments dans un environnement de plateau moyen régressif. L'analyse du morphogroupe montre que, pendant le dépôt des intervalles stratigraphiques analysés, les conditions environnementales sur le site de dépôt de sédiments ne sont pas restées stables comme l'indique la fluctuation du littoral sur un plateau océanique tectoniquement plutôt instable.
Morphogroupes de foraminifères benthiques de la succession du Jurassique moyen àsupérieur de Jhurio Dome, Kutch, Gujarat, Inde: implications paléoenvironnementales
... The dominancy of family Vaginulinidae demonstrates a shallow water, open marine shelf environs and due to near absence of porcelaneous form which indicates proximity to inner shelf, a middle to outer shelf environment is indicated (Bhat et al., 2016;Canales & Henriques, 2008;Farahani et al., 2018;Hjalmarsdottir et al., 2018;Reolid et al., 2019aReolid et al., , 2019bSevillano et al., 2020;Silva et al., 2017Silva et al., , 2020Smoleń, 2012;Talib et al., 2014Talib et al., , 2016bTalib et al., 2012aTalib et al., , 2012bWasim et al., 2021). Preponderance of hyaline species in the assemblages suggests normal salinity under well aerated vicinity (Amao et al., 2018;Bhalla & Abbas, 1984;Bhat et al., 2016;Canales & Henriques, 2008;Chan et al., 2017;Farahani et al., 2018;Gaur & Talib, 2009;Nagy & Johansen, 1991;Silva et al., 2017Silva et al., , 2020Talib & Gaur, 2005;Talib et al., 2012aTalib et al., , 2016aValchev, 2003;Wasim et al., 2021;Zsiborás & Görög, 2020). Dominance of Nodosariidae suggests a distal and well-oxygenated tranquil environment (Bhat et al., 2016;Gaur & Talib, 2009;Silva et al., 2020;Talib et al., 2012aTalib et al., , 2014Ziouit et al., 2021;Zsiborás & Görög, 2020). ...
... In the present foraminiferal assemblages, Lenticulina is the most abundant genus at species and specimen levels, which shows the relatively deep open oceanic shelf environment with excessive quantity of dissolved O 2 (Bhat et al., 2016;Canales & Henriques, 2008;Reolid & Martínez-Ruiz, 2012;Reolid et al., 2008aReolid et al., , 2008bSilva et al., 2017;Smoleń & Iwańczuk, 2018;Talib et al., 2012bTalib et al., , 2014Talib et al., , 2016aWasim et al., 2021). The dominance of shallow to deep infaunal genera like Lenticulina, Nodosaria, Astacolus, Vaginulinopsis and Vaginulina, shows normal O 2 values (Reolid & Martínez-Ruiz, 2012;Reolid et al., 2008aReolid et al., , 2008bTalib et al., 2016b). ...
... The Jhurio Dome assemblages are dominated by the species which are mostly long ranging and various authors emphasised the prospects of ammonites for age determination (Bhat et al., 2016;Gradstein et al., 2017;Kaminski et al., 2020;Sevillano et al., 2020;Silva et al., 2017Silva et al., , 2020Smoleń & Iwańczuk, 2018;Talib & Gaur, 2008;Talib et al., 2012aTalib et al., , 2014Talib et al., , 2016aWasim et al., 2020). Therefore, precise age of this strata using foraminifera is not feasible. ...
Middle to Late Jurassic rocks of Jhurio Dome, Kutch, India yielded fairly rich foraminiferal assemblages comprising 87 species, including 27 species reported for the first time from the Indian region which are illustrated with the help of SEM photomicrographs. Preliminary interpretations regarding palaeoecology and age are attempted. Based on the dominance of Family Vaginulinidae followed by Nodosariidae, Morphogroup J, calcareous hyaline species, and genus Lenticulina, the foraminiferal assemblages of Jhurio Dome appear to be flourishing in an open oceanic deep shelf environment, ranging from mid to outer shelf, with normal to high oxygen level and normal salinity. On the basis of foraminiferal assemblages, a Bajocian to Oxfordian age is assigned to the studied rocks of Jhurio Dome, Kutch, India.
... Stratigraphic and palaeogeographic distribution. Worldwide distribution from the lower Pliensbachian to Callovian (Görög, 2004;Talib et al., 2016). ...
From the upper Pliensbachian–Toarcian interval of the Neotethys, this is the first record of isolated foraminiferal assemblages obtained from the Ammonitico Rosso limestone successions. The studied sections of Bakonycsernye (Hungary) had been dated by ammonites. The foraminiferal fauna extracted by glacial acetic acid yielded 86 benthic foraminiferal taxa. Most specimens belonged to the suborders Spirillinina and Lagenina followed by the Ammodiscina. The representatives of suborders Astrorhizina, Komokioidea, Verneuilinina, Robertinina, and Rotaliina were subordinated; miliolids were absent. Paralingulina csernyensis n. sp. was described from the upper Pliensbachian. The majority of species have wide stratigraphic ranges, however the previously known distributions of seven species changed based on their appearances in these sections. Nevertheless, the stratigraphic distributions of the foraminiferal species enabled accurate dating to stage-level. Based on the comparison of the taxonomic composition with other coeval foraminiferal faunas of the Neotethys, foraminiferal biozones and bioevents are discussed in this paper.
The Middle Jurassic (Bajocian‒Callovian) benthic foraminifera in the Jhura Dome (Kachchh, Western India) were quantitatively analyzed to reconstruct the paleoenvironment. Three distinct assemblages are identified; these are dominated by a particular benthic foraminiferal species, and include, the moderately mesotrophic and well-oxygenated Protomarssonella poddari, moderately mesotrophic and moderately oxygenated Lenticulina subalata, and the highly mesotrophic and moderately oxygenated Epistomina mosquensis–Reophax metensis. Based on species bathymetry, an inner to middle neritic (50‒100 m) depth range is inferred for the studied section. The Bathonian is marked by a carbonate-dominated moderately mesotrophic regime, whereas the Callovian is siliciclastic-dominated and reflects highly mesotrophic conditions. The changes in facies and the trophic regime are attributed to a change in climate from a hot and drier Bathonian to a cooler and wetter Callovian with a progressive increase in the terrigenous input (= nutrient input) and in reduced oxygenation of bottom waters. The Canonical Correspondence Analysis yielded sea level, Benthic Foraminiferal Oxygen Index (BFOI) and paleoproductivity as the main factors controlling the distribution patterns of the studied benthic foraminifera. Additionally, within a shallow epeiric basin and in moderately to well-oxygenated bottom water conditions, the role of nutrients and oxygen availability overrides the influence of bathymetry that at the deeper settings, played a far greater role.
The aim of this work is to examine ecological patterns by analyzing the distribution of foraminifera in the Jurassic sediments of the Jhura area, Kutch, India. 87 foraminiferal species were recovered, which were analyzed for paleoecological interpretations. Three techniques were employed: 1) Diversity indices, in which four episodes are identified based on different indices values; 2) Clustering and nMDS ordination approaches identify four assemblages of benthic foraminifera, which differ in biotic and abiotic characteristics; 3) Morphogroup analysis, which divides the studied sequence into four paleoecological units. Four depositional episodes are recognized within the studied interval: Episode I (Bajocian to Bathonian), Spirillina polygyrata assemblage shows the calm environment with a high diversity of foraminiferal species and enough nutrients in the outer shelf zone having normal salinity and high level of dissolved oxygen. Episode II (Lower Callovian), Miliammina cf. M. valdensis assemblage occurred in a stressed condition with low diversity of species in a shallower portion of mid-shelf in a hypo-saline environment and reduced oxygen condition having low to average food influx. Episode III (Middle to Upper Callovian), Lenticulina subalata assemblage indicates that this portion deposited in stress-free environmental conditions having normal salinity and well‑oxygenated waters in the deepest section of the outer shelf region with high nutrient supply. Episode IV (Oxfordian), Lenticulina bulla assemblage thrived in hyposaline conditions with low oxygen levels and enough nutrients in the deeper portion of the mid-shelf region. An unstable oceanic shelf is interpreted during the deposition of the examined section because of the fluctuations in all inferred parameters.
This paper provides the first record of isolated foraminiferal assemblages from the continuous Aalenian–lower Bajocian succession from the pelagic region of the Neotethys. The studied Tűzkövesárok section B of Bakonycsernye (Hungary) has been well dated by ammonites and consists of Ammonitico Rosso type limestones. The foraminiferal fauna extracted by glacial acetic acid yielded 49 benthic taxa (species and subspecies); protoglobigerinids also occurred. Most specimens belonged to the suborder Spirillinina, followed by the suborder Lagenina and Rotaliina; agglutinated forms were subordinate and miliolids were absent. The majority of the species have wide stratigraphic ranges; moreover, the distributions of 11 species changed based on their appearances in this section. Nevertheless, the Aalenian and Bajocian parts of the section could be distinguished based upon the stratigraphic distributions of some species.
