نتایج جستجو برای: middle cenozoic
تعداد نتایج: 157713 فیلتر نتایج به سال:
[1] The Transantarctic Mountains (TAM) define the western flank of the West Antarctic rift system. Cape Surprise, near the Shackleton Glacier in the central TAM, is the only location along the range’s >3500 km length where upper Paleozoic Beacon Supergroup strata are down-faulted to near sea level. Previous studies have inferred a range front master normal fault accommodates extension and rock ...
[1] High topography in central Asia is perhaps the most fundamental expression of the Cenozoic Indo-Asian collision, yet anunderstandingof the timingandratesofdevelopmentof theTibetan Plateau remains elusive. Here we investigate the Cenozoic thermal historiesofrocksalongtheeasternmarginof theplateauadjacent to the Sichuan Basin in an effort to determine when the steep topographic escarpment tha...
Two soilkaprolite profiles from ridge crest sites in central Georgia were investigated for mineralogical and textural trends to help elucidate the relationship between Cenozoic Coastal Plain deposits landward of the Fall Line and the Piedmont. Result from the study of a 10.5 m thick sequence in Sparta, Georgia reveal a deep lateritic profile showing complete loss of plagioclase, gradational los...
a r t i c l e i n f o a b s t r a c t Keywords: seawater chemistry Cenozoic climate global carbon cycle magnesium isotopes Cooling of Earth's climate over the Cenozoic has been accompanied by large changes in the magnesium and calcium content of seawater whose origins remain enigmatic. The processes that control these changes affect the magnesium isotopic composition of seawater, rendering it a...
Marine planktonic diatoms export carbon to the deep ocean, playing a key role in the global carbon cycle. Although commonly thought to have diversified over the Cenozoic as global oceans cooled, only two conflicting quantitative reconstructions exist, both from the Neptune deep-sea microfossil occurrences database. Total diversity shows Cenozoic increase but is sample size biased; conventional ...
[1] We assess the response of atmospheric CO2 ( pCO2) and ocean chemistry to carbon perturbations, placing modern carbon‐cycle sensitivity in the context of the Cenozoic. We use the carbon‐cycle model LOSCAR to study the effect of perturbations over the past 67 Ma. Our results indicate that atmospheric CO2 and surface ocean pH were slightly more sensitive to carbon perturbations during the Mioc...
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 ab...
It is a preventive strategy that to develop the continue education of migrant workers and to replace number with quality, which will truly avoid labor shortages and improve the quality of workers. To provide adequately continuous education to Cenozoic migrant workers will reduce the turnover rate of their work. But in the process of continuous education for Cenozoic migrant workers, there are s...
Premise of research: The Cenozoic fossil record is crucial for understanding the evolution of the remarkably high diversity of angiosperms. However, the quality and biases of the angiosperm fossil record remain unclear mainly due to the lack of a global database. Methodology: We introduce a new global occurrence-based database for Cenozoic angiosperm macrofossils, the Cenozoic Angiosperm Databa...
[1] The carbon isotope ratio (dC) of plant material is commonly used to reconstruct the relative distribution of C3 and C4 plants in ancient ecosystems. However, such estimates depend on the d C of atmospheric CO2 (dCCO2) at the time, which likely varied throughout Earth history. For this study, we use benthic and planktonic dC and dO records to reconstruct a long‐term record of Cenozoic dCCO2....
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