Late Cretaceous anoxic events, sea-level changes and the evolution of the planktonic foraminifera

1986 ◽  
Vol 21 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Malcolm B. Hart ◽  
Kim C. Ball
Keyword(s):  
Sea Level ◽  
Late Cretaceous ◽  
Planktonic Foraminifera ◽  
Sea Level Changes ◽  
Anoxic Events

Latest Pliensbachian–Toarcian eustatic calibration using shallow-marine sedimentological record coupled with basinal geochemical analyzes

2020 ◽  
Author(s):  
François-Nicolas Krencker ◽  
Alicia Fantasia ◽  
Mohamed El Ouali ◽  
Lahcen Kabiri ◽  
Stéphane Bodin
Keyword(s):  
Sea Level ◽  
Special Focus ◽  
Level Fluctuation ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sequence Stratigraphic ◽  
Sea Level Fluctuations ◽  
Anoxic Events ◽  
Chemical Index Of Alteration ◽  
Sea Level Fluctuation

<p><span>Sea-level fluctuation is an important parameter controlling the sedimentation in deep-marine environments and influenced also the expansion of oxygen-depleted conditions in neritic settings during oceanic anoxic events (OAEs). Despite this fundamental role, sea-level fluctuation remains on a short timescale (<1 Myr) one of the least constrained parameters for numerous OAEs. Here we refine the sequence stratigraphic framework for the uppermost Pliensbachian–Toarcian with a special focus on the Toarcian OAE interval. This study is based on sedimentological and total organic carbon isotope data used to correlate 16 sections located in the central High Atlas (Morocco). Palinspastically, those sections formed a 50-kilometer proximal–distal transect along the northern Gondwana continental shelf, which allow reconstructing the shoreline migration through time and space. Our sequence stratigraphic interpretation is then compared to the geochemical signals (e.g. detrital index, chemical index of alteration) measured on samples collected in deep-environment settings from numerous basins distributed worldwide. Our study shows that the relative sea-level changes recorded in Morocco can be correlated over large distances across those basins, indicating that the relative sea-level changes were driven by eustatic fluctuations. This study gives insights into the relationship between relative sea-level fluctuations and the geochemical record.</span></p>

scholarly journals Short-Term Sea Level Changes of the Upper Cretaceous Carbonates: Calibration between Palynomorphs Composition, Inorganic Geochemistry, and Stable Isotopes

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1099
Author(s):  
Ahmed Mansour ◽  
Thomas Gentzis ◽  
Michael Wagreich ◽  
Sameh S. Tahoun ◽  
Ashraf M.T. Elewa
Keyword(s):  
Sea Level ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Freshwater Algae ◽  
Sea Level Changes ◽  
Short Term ◽  
Sea Level Oscillations ◽  
Rising Sea Level ◽  
Southern Tethys

Widespread deposition of pelagic-hemipelagic sediments provide an archive for the Late Cretaceous greenhouse that triggered sea level oscillations. Global distribution of dinoflagellate cysts (dinocysts) exhibited a comparable pattern to the eustatic sea level, and thus, considered reliable indicators for sea level and sequence stratigraphic reconstructions. Highly diverse assemblage of marine palynomorphs along with elemental proxies that relate to carbonates and siliciclastics and bulk carbonate δ13C and δ18O from the Upper Cretaceous Abu Roash A Member were used to reconstruct short-term sea level oscillations in the Abu Gharadig Basin, southern Tethys. Additionally, we investigated the relationship between various palynological, elemental, and isotope geochemistry parameters and their response to sea level changes and examined the link between these sea level changes and Late Cretaceous climate. This multiproxy approach revealed that a long-term sea-level rise, interrupted by minor short-term fall, was prevalent during the Coniacian-earliest Campanian in the southern Tethys, which allowed to divide the studied succession into four complete and two incomplete 3rd order transgressive-regressive sequences. Carbon and oxygen isotopes of bulk hemipelagic carbonates were calibrated with gonyaulacoids and freshwater algae (FWA)-pteridophyte spores and results showed that positive δ13Ccarb trends were consistent, in part, with excess gonyaulacoid dinocysts and reduced FWA-spores, reinforcing a rising sea level and vice versa. A reverse pattern was shown between the δ18Ocarb and gonyaulacoid dinocysts, where negative δ18Ocarb trends were slightly consistent with enhanced gonyaulacoid content, indicating a rising sea level and vice versa. However, stable isotope trends were not in agreement with palynological calibrations at some intervals. Therefore, the isotope records can be used as reliable indicators for reconstructing changes in long-term sea level rather than short-term oscillations.

Cenozoic Benthic Foraminifera Case Histories of Paleoceanographic and Sea-Level Changes

1982 ◽  
Vol 6 ◽  
pp. 107-126 ◽  
Author(s):  
Kenneth G. Miller
Keyword(s):  
Sea Level ◽  
Benthic Foraminifera ◽  
Deep Sea ◽  
Planktonic Foraminifera ◽  
Environmental Studies ◽  
Sea Level Changes ◽  
Case Histories ◽  
Reasonable Degree ◽  
Near Future ◽  
And Sea Level

Since the inception of their use in commercial micropaleontology, benthic foraminifera have proven to be eminently useful in the solution of geological problems. The utilitarian credentials of benthic foraminifera in estimating paleodepths from marsh through neritic environments with a reasonable degree of accuracy and to indicate approximate ages (viz. subdivision of series/epochs) have been established in both commercial and academic applications. Benthic foraminifera are generally more resistant to dissolution than planktonic foraminifera, and have wide distributions; many taxa have restricted stratlgraphic ranges, making them suitable for correlation and paleo-environmental studies. Yet, three problems have tended to limit the utility of benthic foraminifera: 1) there is a lack of uniformity in taxonomy (Boltovskoy, 1980; Douglas & Woodruff, 1982); 2) attempts to erect zonal schemes using benthic foraminifera have resulted in boundaries which are later proven to be diachronous relative to planktonic zonatlons (e.g. the California provincial stages, Poore, 1976); and 3) attempts to interpret paleodepths from deep-sea benthic foraminifera have produced widely-varying results. One could perhaps conclude, as Boltovskoy (1965a) did over a decade ago, that these problems indicate “…the near future of this science is rather bleak.”

scholarly journals Paleozoic–Mesozoic Eustatic Changes and Mass Extinctions: New Insights from Event Interpretation

Life ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 281
Author(s):  
Dmitry A. Ruban
Keyword(s):  
Sea Level ◽  
Late Cretaceous ◽  
Mass Extinction ◽  
Early Jurassic ◽  
Late Devonian ◽  
Mass Extinctions ◽  
Sea Level Changes ◽  
Event Interpretation ◽  
Marine Realm ◽  
Global Sea Level

Recent eustatic reconstructions allow for reconsidering the relationships between the fifteen Paleozoic–Mesozoic mass extinctions (mid-Cambrian, end-Ordovician, Llandovery/Wenlock, Late Devonian, Devonian/Carboniferous, mid-Carboniferous, end-Guadalupian, end-Permian, two mid-Triassic, end-Triassic, Early Jurassic, Jurassic/Cretaceous, Late Cretaceous, and end-Cretaceous extinctions) and global sea-level changes. The relationships between eustatic rises/falls and period-long eustatic trends are examined. Many eustatic events at the mass extinction intervals were not anomalous. Nonetheless, the majority of the considered mass extinctions coincided with either interruptions or changes in the ongoing eustatic trends. It cannot be excluded that such interruptions and changes could have facilitated or even triggered biodiversity losses in the marine realm.

scholarly journals Timing of the Middle Miocene Badenian Stage of the Central Paratethys

2014 ◽  
Vol 65 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Johann Hohenegger ◽  
Stjepan Ćorić ◽  
Michael Wagreich
Keyword(s):  
Sea Level ◽  
Middle Miocene ◽  
Planktonic Foraminifera ◽  
Sea Level Changes ◽  
Vienna Basin ◽  
Central Paratethys ◽  
Polarity Reversals ◽  
Global Events ◽  
Geomagnetic Polarity ◽  
Climate Transition

Abstract A new and precisely defined chronometric subdivision of the Badenian (Middle Miocene, regional stage of Central Paratethys) is proposed. This uses global events, mainly geomagnetic polarity reversals as correlated chronometric boundaries, supported by climatic and sea-level changes in addition to isotope events and biostratigraphic data. The Karpatian/ Badenian boundary lies at 16.303 Ma, at the top of Chron C5Cn.2n, which is near the base of the Praeorbulina sicana Lowest-occurrence Zone (LOZ). The Badenian/Sarmatian boundary is placed at the top of polarity Chron C5Ar.2n, thus at 12.829 Ma. In relation to three sea level cycles TB 2.3, TB 2.4 and TB 2.5 and astronomically confirmed data, the Badenian can be divided into three parts of nearly equivalent duration. The Early Badenian as newly defined here ranges from 16.303 to 15.032 Ma (top of polarity Chron C5Bn.2n). The younger boundary correlates roughly to the base of the planktonic foraminifera Orbulina suturalis LOZ at 15.10 Ma, the HO (Highest Occurrence) of the nannofossil Helicosphaera ampliaperta at 14.91 Ma (NN4/NN5 boundary) and the Lan2/Ser1 sequence boundary at 14.80 Ma. The subsequent Mid Badenian ranges from 15.032 Ma to 13.82 Ma; the latter datum correlates with the base of the Serravallian, characterized by a strong global cooling event reflected in the oxygen isotope event Mi3b. The main part of cycle TB 2.4 falls into the Mid Badenian, which can be subdivided by a short cooling event at 14.24 Ma during the Middle Miocene Climate Transition (14.70 to 13.82 Ma). The HCO (Highest common occurrence) of the nannofossil Helicosphaera waltrans at 14.357 Ma supports this division, also seen in the tropical plankton Zones M6 Orbulina suturalis LOZ and M7 Fohsella peripheroacuta LOZ that correspond roughly to the lower and upper Lagenidae zones in the Vienna Basin, respectively. The Late Badenian is delimited in time at the base to 13.82 Ma by the Langhian/Serravallian boundary and at the top by the top of polarity Chron C5Ar.2n at 12.829 Ma. The Mediterranean Langhian/Serravallian boundary can be equated with the Mid/Late Badenian boundary at 13.82 Ma. However, the Karpatian/Badenian boundary at 16.303 Ma, a significant event easily recognizable in biostratigraphy, paleoclimate evolution and sequence stratigraphy, cannot be equated with the proposed global Burdigalian/Langhian, and thus Early/Middle Miocene boundary, at 15.974 Ma

Has Earth ever been ice-free? Implications for glacio-eustasy in the Cretaceous greenhouse age using high-resolution sequence stratigraphy

2020 ◽  
Vol 133 (1-2) ◽  
pp. 243-252 ◽  
Author(s):  
Wen Lin ◽  
Janok P. Bhattacharya ◽  
Brian R. Jicha ◽  
Brad S. Singer ◽  
William Matthews
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Late Cretaceous ◽  
High Frequency ◽  
Tectonic Setting ◽  
Reciprocal Relationship ◽  
Sea Level Changes ◽  
Sea Levels ◽  
Shallow Marine ◽  
Water Tables

Abstract Controls on high-frequency sequences formed during super-greenhouse conditions in the Late Cretaceous Western Interior Seaway remain equivocal because of the active foreland basin tectonic setting and the lack of direct evidence of polar glaciations to support a glacio-eustatic origin. This paper quantifies eustatic sea-level changes based on high-resolution sequence stratigraphic analysis and improved chronometry of shallow marine deposits of the Late Cretaceous Gallup Sandstone in New Mexico, USA. Backstripping techniques remove tectonic and compactional subsidence and enable quantification of the magnitude of eustatic sea-level change, that allow evaluation of the dominant controls on the high-frequency sequences to resolve the role of orbitally controlled, climate-driven eustasy versus tectonics. Sixty-five parasequences, constituting 29 parasequence sets and 12 sequences are identified in the ∼1.2 m.y. duration of the Late Cretaceous Gallup system. New 40Ar/39Ar dating of bentonites constrains the durations of the individual parasequences, parasequence sets, and sequences, and that these match Milankovitch periodicity, indicating an orbital climate control. The magnitudes of sea-level changes between parasequences range between −28 m and +22 m, which are compatible with hypotheses of both aquifer and glacio-eustasy. Aquifer-eustasy predicts a reciprocal relationship between floodplain cycles and shallow marine sequences, such that aquifer drawdown and falling water tables should correlate to rising sea levels (highstands), whereas increased aquifer storage and rising water tables should correlate to falling sea levels (lowstands). Our preliminary observations show synchronous, versus reciprocal, relationships that may be more compatible with a glacio-eustatic origin. The results of this study support the hypothesis that the Cretaceous greenhouse was marked by high-frequency, low-amplitude glaciations driven by orbital climate cycles, but further work is required to evaluate the contribution of aquifer-eustasy.

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