نتایج جستجو برای: upper miocene
تعداد نتایج: 210849 فیلتر نتایج به سال:
The Oligocene–Miocene Maykop Group sediments, mainly composed of illite–smectite, store mercury in strongly variable concentrations from 10 to 920 μg/kg. Extremely high Hg levels (98–920 μg/kg) coupled with abnormal mercury-to-total organic carbon (TOC) ratios (Hg/TOC = 109 3000 μg/kg/wt%; TOC 0.2 wt% 1.2 wt%) were measured the Middle marine shales that deposited deepwater Indol–Kuban Basin und...
a Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303, China b Key Laboratory of Biogeography and Biodiversity, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China c Institute of Systematic Botany, University of Zürich, Zürich, 8008, Switzerland d Graduate University of Chinese Academy of Sc...
abstract the variables affecting the nature of reading comprehension can be classified into two general categories: reader’s variables, and text variables (alderson, 2000). despite the wave of research on vocabulary knowledge as reader’s variable, the role of this knowledge in c-test as a text-dependent test and its interaction with lexical cohesion of the test as a text feature has remained a...
Fossil specimens of Neotropical gymnotiform electric fishes from the Yecua Formation (Upper Miocene, Parana basin, Bolivia) are analyzed in the context of a comprehensive study of gymnotiform relationships. Each fossil is analyzed individually and placed in the phylogeny according to characters it actually possesses. Some of the fossils previously referred to Humboldtichthys kirschbaumi can be ...
There is a considerable controversy about whether western Amazonia was ever covered by marine waters during the Miocene [23 to 5 Ma (million years ago)]. We investigated the possible occurrence of Miocene marine incursions in the Llanos and Amazonas/Solimões basins, using sedimentological and palynological data from two sediment cores taken in eastern Colombia and northwestern Brazil together w...
Tabriz Basin has had extensive Cenozoic and Quaternary volcanic activity and lies in NW Iran within the collision zone of the Arabian and Eurasian plates. Formations in the region consist of siliciclastic rocks of the Miocene age (Upper red formation), along with younger dacite volcanic rocks. The Bahlul Daghi volcanic dome in the south of Spiran is variable in terms of the composition between ...
Echinoids fauna are common and distributed in the Lower Miocene deposits of the Bagher Abad area, northeast Isfahan, Central Iran.There are six Echinoid taxa belonging to the Echinoidea Class that can be described as: Clypeaster intermedius, Prinocidaris sp. andspines related to: Eucidaris zaemays, Stylocidaris Polyacantha, Spatangoid sp. and Prinocidaris sp. Bivalves, Foraminifers,Bryozoans, B...
The Late Miocene development of faunas and environments in western Eurasia is well known, but the climatic and environmental processes that controlled its details are incompletely understood. Here we map the rise and fall of the classic Pikermian fossil mammal chronofauna between 12 and 4.2 Ma, using genus-level faunal similarity between localities. To directly relate land mammal community evol...
This study presents results from the Community Climate System Model 3 (CCSM3) forced with early to middle Miocene (;20–14 Ma) vegetation, topography, bathymetry, and modern CO2. A decrease in the meridional temperature gradient of 6.58C and an increase in global mean temperature of 1.58C are modeled in comparison with a control simulation forced with modern boundary conditions. Seasonal polewar...
The >>Open Source<< Perspective deals with the spatio-temporal distribution pattern of Miocene hominids and suggests a pan-African perspective on the evolution of bipedalism. The shrinking of the rainforest from the Middle Miocene resulted in a selection pressure that was similar along its wide-stretched margin. The earliest hominids might represent co-existing geographic variants.
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