نتایج جستجو برای: cenozoic
تعداد نتایج: 2977 فیلتر نتایج به سال:
The future impacts of anthropogenic global change on marine ecosystems are highly uncertain, but insights can be gained from past intervals of high atmospheric carbon dioxide partial pressure. The long-term geological record reveals an early Cenozoic warm climate that supported smaller polar ecosystems, few coral-algal reefs, expanded shallow-water platforms, longer food chains with less energy...
The decline of species richness from equator to pole, or latitudinal diversity gradient (LDG), is nearly universal among clades of living organisms, yet whether it was such a pervasive pattern in the geologic past remains uncertain. Here, we calculate the strength of the LDG for terrestrial mammals in North America over the past 65 My, using 27,903 fossil occurrences of Cenozoic terrestrial mam...
Global climate change is having profound impacts on the natural world. However, climate influence on faunal dynamics at macroevolutionary scales remains poorly understood. In this paper we investigate the influence of climate over deep time on the diversity patterns of Cenozoic North American mammals. We use factor analysis to identify temporally correlated assemblages of taxa, or major evoluti...
Penguins (Sphenisciformes) inhabit some of the most extreme environments on Earth. The 60+ Myr fossil record of penguins spans an interval that witnessed dramatic shifts in Cenozoic ocean temperatures and currents, indicating a long interplay between penguin evolution and environmental change. Perhaps the most celebrated example is the successful Late Cenozoic invasion of glacial environments b...
This article provides a background for scientists interested in a general overview of the geology and geomorphology of Turkmenistan. The basement of Turkmenistan is a complex amalgamation of arc-related terranes developed in the Asiatic and northern Paleotethys oceanic domains during Late Paleozoic to Triassic times. A major part of the country coincides with the Turan Platform, where a thick s...
In this paper the geometrical relationship of the folds which exist in the Folded Zagros Mountains, including Asef Mountain (northern Iran), were studied. The southern and western zones of the Zagros Mountains are called the Folded Zagros. These zones extend approximately 1,375 km in length with a width ranging from 120 to 250 km. Asef Mountain is located in northern Shiraz (from northern Sarda...
The pyroclastic rocks of "The Crater", South Island, New Zealand belong to the Miocene, alkaline basaltic Dunedin Volcanic Group and represent an individual eruptive center with possible multiple vents. Three pyroclastic units have been separated at the study area based on textural and compositional features as well as their stratigraphic positions. The central part of The Crater comprises basa...
Two North American fossil species of large felids, hitherto regarded as Late Cenozoic pumas (mountain lion), are in fact closely related to the living cheetah, Acinonyx, of Africa and Eurasia. A new subgenus (Miracinonyx) is proposed for the American species. Cheetahs and pumas may have had a common ancestor in the Miocene of North America.
Well-preserved, actively deforming folds in the Tien Shan of Kyrgyzstan provide a natural laboratory for the study of the evolution of thrust-related folds. The uplifted limbs of these folds comprise weakly indurated Cenozoic strata that mantle well-lithified Palaeozoic bedrock. Their contact is a regionally extensive unconformity that provides a persistent and readily traceable marker horizon....
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