Climate variability and paleoceanography during the Late Cretaceous: Evidence from palynology, geochemistry and stable isotopes analyses from the southern Tethys

2021 ◽  
pp. 104831
Author(s):  
Ahmed Mansour ◽  
Michael Wagreich ◽  
Susanne Gier ◽  
Thomas Gentzis ◽  
Urs Kloetzli ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Climate Variability ◽  
Late Cretaceous ◽  
Southern Tethys

Correlation of Grassy Lake and Cedar Lake ambers using infrared spectroscopy, stable isotopes, and palaeoentomology

2008 ◽  
Vol 45 (9) ◽  
pp. 1061-1082 ◽  
Author(s):  
Ryan C. McKellar ◽  
Alexander P. Wolfe ◽  
Ralf Tappert ◽  
Karlis Muehlenbachs
Keyword(s):  
Stable Isotopes ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Late Cretaceous ◽  
Western Canada ◽  
Long Distance ◽  
Geochemical Fingerprinting ◽  
Long Distance Transport ◽  
Distance Transport

The Late Cretaceous Grassy Lake and Cedar Lake amber deposits of western Canada are among North America’s most famous amber-producing localities. Although it has been suggested for over a century that Cedar Lake amber from western Manitoba may be a secondary deposit having originated from strata in Alberta, this hypothesis has not been tested explicitly using geochemical fingerprinting coupled to comparative analyses of arthropod faunal content. Although there are many amber-containing horizons associated with Cretaceous coals throughout Alberta, most are thermally mature and brittle, thus lacking the resilience to survive long distance transport while preserving intact biotic inclusions. One of the few exceptions is the amber found in situ at Grassy Lake. We present a suite of new analyses from these and other Late Cretaceous ambers from western Canada, including stable isotopes (H and C), Fourier transform infrared (FTIR) spectra, and an updated faunal compendium for the Grassy and Cedar lakes arthropod assemblages. When combined with amber’s physical properties and stratigraphic constraints, the results of these analyses confirm that Cedar Lake amber is derived directly from the Grassy Lake amber deposit or an immediate correlative equivalent. This enables the palaeoenvironmental context of Grassy Lake amber to be extended to the Cedar Lake deposit, making possible a more inclusive survey of Cretaceous arthropod faunas.

Late Cretaceous fluvial hydrology and dinosaur behavior in southern Utah, USA: Insights from stable isotopes of biogenic carbonate

2019 ◽  
Vol 516 ◽  
pp. 152-165
Author(s):  
Victoria F. Crystal ◽  
Erica S.J. Evans ◽  
Henry Fricke ◽  
Ian M. Miller ◽  
Joseph J.W. Sertich
Keyword(s):  
Stable Isotopes ◽  
Late Cretaceous ◽  
Biogenic Carbonate

scholarly journals Stable isotopes and predation marks shed new light on ammonoid habitat depth preferences

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marcin Machalski ◽  
Krzysztof Owocki ◽  
Zofia Dubicka ◽  
Oksana Malchyk ◽  
Weronika Wierny
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Late Cretaceous ◽  
Late Paleozoic ◽  
Planktic Foraminifera ◽  
Habitat Depth ◽  
Local Populations ◽  
Isotope Data ◽  
Geochemical Studies ◽  
Stable Isotope Data

AbstractAmmonoids are extinct cephalopods with external shells which predominated in many late Paleozoic and Mesozoic marine ecosystems. Stable isotope data from ammonoid shells constitute primary tools for understanding their palaeohabitats. However, in most sedimentary successions globally the aragonitic shells of ammonoids are dissolved during fossilisation process and therefore not available for geochemical studies. We overcome this taphonomic bias by analysing the better preservable calcitic elements of the ammonoid jaws (aptychi). We study moulds and aptychi of two successive members, temporal subspecies in our interpretation, of a scaphitid evolutionary lineage from a Late Cretaceous chalk succession in Poland. In order to reconstruct their habitat depth preferences, we apply the powerful combination of stable isotope data from aptychi and co-occurring benthic and planktic foraminifera with an analysis of predation marks preserved on scaphitid specimens. On this basis we conclude that the populations of the older subspecies led a nektic, and those of the younger subspecies, a nektobenthic lifestyle. The shift in habitat depth preferences took place probably as a response of local populations to the shallowing of the sea. Previous studies largely assumed stable depth preferences for ammonoid species, genera and even higher clades. Our study casts doubts over such generalizations by pointing out that ammonoids could have been more flexible in their depth-related behaviour than anticipated.

scholarly journals Morphometric changes in two Late Cretaceous calcareous nannofossil lineages support diversification fueled by long-term cooling

2020 ◽  
Author(s):  
mohammad javad razmjooei ◽  
Nicolas Thibault ◽  
Anoshiravan Kani
Keyword(s):  
New Species ◽  
Climate Variability ◽  
Late Cretaceous ◽  
Calcareous Nannofossil ◽  
The Core ◽  
Two New Species ◽  
Climatic Evolution ◽  
Biometric Measurements

Biometric measurements undertaken on two relevant taxa, Cribrosphaerella and Microrhabdulus, make the core of this chapter. The results of this paper allowed us to describe two new species of Microrhabdulus and suggest that the peculiar climatic evolution across the Campanian and Maastrichtian triggered a rise in diversity and size of nannofossils following both Cope’s and Bergmann’s rules and its possible effects on the morphometric changes of Cribrosphaerella and Microrhabdulus. In this study, the link between climate variability and diversification has been discussed, and two new species of Microrhabdulus are described.

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.

scholarly journals Origin and Evolution of Saline Spring Water in North and Central Laos Based on Hydrochemistry and Stable Isotopes (δD, δ18O, δ11B, and δ37Cl)

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3568
Author(s):  
Xiwei Qin ◽  
Haizhou Ma ◽  
Xiying Zhang ◽  
Xiasong Hu ◽  
Guorong Li ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Late Cretaceous ◽  
Carbonate Rocks ◽  
Volcanic Rocks ◽  
Atmospheric Precipitation ◽  
Mining Area ◽  
Geochemical Type ◽  
Origin And Evolution ◽  
Deep Circulation ◽  
Saline Springs

This paper discusses the origin and evolution of saline springs in north and central Laos, based on chemical and stable isotopes (δD, δ18O, δ11B, and δ37Cl). All the saline springs in this study are of the Na–Cl geochemical type. The geochemical and water isotope values suggest that the saline springs in this study are mainly derived from meteoric water and/or ice and snow melt from the surrounding mountains and that they also experienced strong evaporation and intense rock–water interactions. The ionic ratios, characteristic coefficients, ternary Ca–SO4–HCO3 phase diagrams, and saturation indices of minerals show that the dissolution of halite, sulfate, and carbonate rocks may be the solute sources for saline springs in this study, whereas the underground brines in the Thakhek potash mining area are geochemically influenced by the dissolution of carnallite and sylvite. The global geothermal δ11B–Cl/B relationship and δ11B values (5.50 to 36.01‰) of saline springs suggest a continental origin of B. This B is most likely derived from marine carbonate rocks and marine evaporates (gypsum and halite) of the late Cretaceous, which is similar to the saline springs of the Nangqen–Qamdo–Simao Salt Basin. The δ37Cl value (−0.12 to +0.79) and the Cl/Br ratio (4076 to 9853) show that dissolution of late cretaceous marine halite layers, atmospheric precipitation, and water–rock interactions between volcanic rocks, mudstones, and sandstone can restrict the δ37Cl values in saline springs. Results from silica geothermometry and multi–mineral equilibrium diagrams indicate that the reservoir temperatures for the saline springs range from 87–137 °C and experience deep circulation. Hydrochemical characteristic coefficients suggest that saline springs in the Muang Say basin may have leached sylvinite and carnallite and that the potash exploration prospect in this area is relatively good.

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