A major planktic foraminiferal species turnover accompanied by a dramatic reduction in shell size, a fundamental change in shell architecture, and a precipitous drop in the abundance of planktic relative to benthic species occurs across the Aptian/Albian boundary interval (AABI) at globally distributed deep-sea sections. Extinction of the large and distinctive planktic foraminifer Paraticinella...

Pedogenic carbonate samples collected from three Lower Cretaceous (Aptian–Albian) fossil localities in Texas and Oklahoma were analyzed to develop paleoatmospheric pCO2 estimates by measuring the stable carbon isotopes of pedogenic calcite their co-existing occluded organic matter. Calcite ?13C values ranged ?10.9‰ ?4.4‰ while matter ?27.3‰ ?21.1‰. These isotope measurements combined with tempe...

Abstract. The Early Cretaceous is characterized by warm background temperatures (i.e., greenhouse climate) and carbon cycle perturbations that are often marked ocean anoxic events (OAEs) associated shifts in the hydrologic cycle. Higher-resolution records of terrestrial marine δ13C δ18O (both carbonates organics) suggest climate during Aptian–Albian, including a period with OAE 1a early Aptian ...

Current carbon and sulphur isotope ratios (δ(13)C and δ(34)S) suggest there were major shifts in partitioning between reduced and oxidised reservoirs of carbon and sulphur during the Early Cretaceous. However, the δ(13)C and δ(34)S records are composed from different Ocean Drilling Program sites and are hard to correlate at high resolution. We present high-resolution Aptian δ(13)C(org) and δ(34...

the investigated section cropping out in kuh-e-banesh, zagros basin (southern iran) is represented by limestone, cherty beds and marllevels bearing abundant planktonic foraminifers, radiolarian microfaunas, and ammonite imprints. for the first time, well to moderatelypreserved forms of planktonic foraminifera have been extracted from black shale and marls levels. extracted biota was studied wit...

Cretaceous planktonic foraminifers from Ocean Drilling Program (ODP) Leg 130 consist of two age groups: one dominantly Aptian in age and the other dominantly Maastrichtian. The oldest dated sediments from Ontong Java Plateau occur at ODP Site 807 and are assigned to the early Aptian Globigerinelloides blowi Zone. The assemblage correlates closely with Aptian foraminifers from Deep Sea Drilling ...

Some of the major Carbon cycle perturbations Phanerozoic occurred during Aptian, in relation to magmatism. The highest temperatures reconstructed for Cretaceous Period correspond Oceanic Anoxic Event early Aptian (OAE 1a), an episode accelerated global change. Here we present a chemostratigraphic study based on osmium isotopes integrated with high-resolution Carbon-Oxygen stable isotope data fr...

Fifty-four coal clast samples in the siliciclastic rocks (e.g., sandstone and conglomerate) were collected from cores of two-deep research wells (K20H K20K) drilled at Kozlu coalfield Zonguldak Basin, for first time, they evaluated using mineralogy by XRD SEM-EDX random vitrinite reflectance (%Rr) measurements order to find out their origin timing. Petrographic observations on polish surfaces s...

Abstraet The amount and type of organic matter present in an exceptionally complete upper Aptian to lower Cenomanian sequence of sediments from ODP site 763 on the Exmouth Plateau has been determined. Organic carbon concentrations average 0.2~o. Organic matter is marine in origin, and its production and preservation was low over the ca. 20-million-year interval recorded by this sequence. Becaus...