Topic
Cretaceous
About: Cretaceous is a research topic. Over the lifetime, 20414 publications have been published within this topic receiving 528831 citations. The topic is also known as: Cretaceous period.
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TL;DR: An effort has been made to develop a realistic and accurate time scale and widely applicablechronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework.
Abstract: Advances in sequence stratigraphy and the development of depositional models have helped explain the origin of genetically related sedimentary packages during sea level cycles. These concepts have provided the basis for the recognition of sea level events in subsurface data and in outcrops of marine sediments around the world. Knowledge of these events has led to a new generation of Mesozoic and Cenozoic global cycle charts that chronicle the history of sea level fluctuations during the past 250 million years in greater detail than was possible from seismic-stratigraphic data alone. An effort has been made to develop a realistic and accurate time scale and widely applicable chronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework. A description of this approach and an account of the results, illustrated by sea level cycle charts of the Cenozoic, Cretaceous, Jurassic, and Triassic intervals, are presented.
6,928 citations
TL;DR: An adjusted geomagnetic reversal chronology for the Late Cretaceous and Cenozoic is presented that is consistent with astrochronology in the Pleistocene and Pliocene and with a new timescale for the Mesozoic.
Abstract: Recently reported radioisotopic dates and magnetic anomaly spacings have made it evident that modification is required for the age calibrations for the geomagnetic polarity timescale of Cande and Kent (1992) at the Cretaceous/Paleogene boundary and in the Pliocene. An adjusted geomagnetic reversal chronology for the Late Cretaceous and Cenozoic is presented that is consistent with astrochronology in the Pleistocene and Pliocene and with a new timescale for the Mesozoic. The age of 66 Ma for the Cretaceous/Paleogene (K/P) boundary used for calibration in the geomagnetic polarity timescale of Cande and Kent (1992) (hereinafter referred to as CK92) was supported by high precision laser fusion Ar/Ar sanidine single crystal dates from nonmarine strata in Montana. However, these age determinations are now
3,582 citations
TL;DR: Long-term sea level peaked at 100 ± 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred, and presents a new sea-level record for the past 100 million years.
Abstract: We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 ± 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations, reflecting ice-volume change on the 10 4 - to 10 6 -year scale, but a link between oxygen isotope and sea level on the 10 7 -year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present).
2,740 citations
TL;DR: GTS2012 as mentioned in this paper summarizes the international divisions and ages in the Geologic Time Scale, published in 2012, since 2004, when GTS2004 was detailed, major developments have taken place that directly bear and have considerable impact on the intricate science of geologic time scaling.
Abstract: This report summarizes the international divisions and ages in the Geologic Time Scale, published
in 2012 (GTS2012). Since 2004, when GTS2004 was detailed, major developments have taken place
that directly bear and have considerable impact on the intricate science of geologic time scaling. Precam brian
now has a detailed proposal for chronostratigraphic subdivision instead of an outdated and abstract chronometric
one. Of 100 chronostratigraphic units in the Phanerozoic 63 now have formal definitions, but stable
chronostratigraphy in part of upper Paleozoic, Triassic and Middle Jurassic/Lower Cretaceous is still wanting.
Detailed age calibration now exist between radiometric methods and orbital tuning, making 40Ar-39Ar dates
0.64% older and more accurate. In general, numeric uncertainty in the time scale, although complex and not
entirely amenable to objective analysis, is improved and reduced. Bases of Paleozoic, Mesozoic and Cenozoic
are bracketed by analytically precise ages, respectively 541 0.63, 252.16 0.5, and 65.95 0.05 Ma.
High-resolution, direct age-dates now exist for base-Carboniferous, base-Permian, base-Jurassic, base-Cenomanian
and base-Eocene. Relative to GTS2004, 26 of 100 time scale boundaries have changed age, of which
14 have changed more than 4 Ma, and 4 (in Middle to Late Triassic) between 6 and 12 Ma. There is much
higher stratigraphic resolution in Late Carboniferous, Jurassic, Cretaceous and Paleogene, and improved integration
with stable isotopes stratigraphy. Cenozoic and Cretaceous have a refined magneto-biochronology.
The spectacular outcrop sections for the Rosello Composite in Sicily, Italy and at Zumaia, Basque Province,
Spain encompass the Global Boundary Stratotype Sections and Points for two Pliocene and two Paleocene
stages. Since the cycle record indicates, to the best of our knowledge that the stages sediment fill is stratigraphically
complete, these sections also may fulfill the important role of stage unit stratotypes for three of
these stages, Piacenzian, Zanclean and Danian
1,892 citations
Journal Article•
TL;DR: In this article, an interpretation of these events as the result of the interplay of two major geologic and climatic factors is given, namely, the Late Cretaceous transgression which increased the area and volume of shallow epicontinental and marginal seas and was accompanied by an increase in the production of organic carbon; and the existence of an equable global climate which reduced the supply of cold oxygenated bottom water to the world ocean.
Abstract: Organic carbon-rich sediments are globally developed in pelagic sedimentary sequences of Aptian-Albian and Cenomanian-Turonian age. They formed in a variety of paleo-bathymetric settings including oceanic plateaus and basins, continental margins and shelf seas. The widespread nature of these deposits suggests that they were not strictly controlled by local basin geometry but were a product of ″Oceanic Anoxic Events″ . Interpretation of these events as the result of the interplay of two major geologic and climatic factors is given. The Late Cretaceous transgression which increased the area and volume of shallow epicontinental and marginal seas and was accompanied by an increase in the production of organic carbon; and the existence of an equable global climate which reduced the supply of cold oxygenated bottom water to the world ocean. This combination of climatic and hypsographic conditions favoured the formation of an expanded oxygen-minimum layer and where this intersected the sediment-water interface, organic carbon-rich deposits could be formed, these being records of ″Oceanic Anoxic Events″ .
1,420 citations