14 resultados para South Asia--Maps--Early works to 1800

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Animal domestication was a major step forward in human prehistory, contributing to the emergence of more complex societies. At the time of the Neolithic transition, zebu cattle (Bos indicus) were probably the most abundant and important domestic livestock species in Southern Asia. Although archaeological evidence points toward the domestication of zebu cattle within the Indian subcontinent, the exact geographic origins and phylogenetic history of zebu cattle remains uncertain. Here, we report evidence from 844 zebu mitochondrial DNA (mtDNA) sequences surveyed from 19 Asiatic countries comprising 8 regional groups, which identify 2 distinct mitochondrial haplogroups, termed I1 and I2. The marked increase in nucleotide diversity (P < 0.001) for both the I1 and I2 haplogroups within the northern part of the Indian subcontinent is consistent with an origin for all domestic zebu in this area. For haplogroup I1, genetic diversity was highest within the Indus Valley among the three hypothesized domestication centers (Indus Valley, Ganges, and South India). These data support the Indus Valley as the most likely center of origin for the I1 haplogroup and a primary center of zebu domestication. However, for the I2 haplogroup, a complex pattern of diversity is detected, preventing the unambiguous pinpointing of the exact place of origin for this zebu maternal lineage. Our findings are discussed with respect to the archaeological record for zebu domestication within the Indian subcontinent.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

To resolve the phylogeny of the autochthonous mitochondrial DNA (mtDNA) haplogroups of India and determine the relationship between the Indian and western Eurasian mtDNA pools more precisely, a diverse subset of 75 macrohaplogroup N lineages was chosen fo

Relevância:

100.00% 100.00%

Publicador:

Resumo:

By using 19 Y chromosome biallelic markers and 3 Y chromosome microsatellite markers, we analyzed the genetic structure of 31 indigenous Sino-Tibetan speaking populations (607 individuals) currently residing in East, Southeast, and South Asia. Our results showed that a T to C mutation at locus M122 is highly prevalent in almost all of the Sino-Tibetan populations, implying a strong genetic affinity among populations in the same language family. Furthermore, the extremely high frequency of H8, a haplotype derived from M122C, in the Sino-Tibetan speaking populations in the Himalayas including Tibet and northeast India indicated a strong bottleneck effect that occurred during a westward and then southward migration of the founding population of Tibeto-Burmans. We, therefore, postulate that the ancient people, who lived in the upper-middle Yellow River basin about 10,000 years ago and developed one of the earliest Neolithic cultures in East Asia, were the ancestors of modem Sino-Tibetan populations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The population genetic structure of the crimson snapper Lutjanus erythropterus in East Asia was examined with a 427-bp hypervariable portion of the mtDNA control region. A total of 262 samples were collected and 75 haplotypes were obtained. Neutrality tests (Tajima's and Fu's) suggested that Lutjanus erythropterus in East Asia had experienced a bottleneck followed by population expansion since the late Pleistocene. Despite the low phylogeographic structures in mtDNA haplotypes, a hierarchical examination of populations in 11 localities from four geographical regions using analysis of molecular variance (AMOVA) indicated significant genetic differentiation among regions (Phi(CT) = 0.08564, p < 0.01). Limited gene flow between the eastern region (including a locality in the western Pacific Ocean and two localities in the East Sea) and three geographic regions of the South China Sea largely contributed to the genetic subdivision. However, comparisons among three geographic regions of the South China Sea showed little to no genetic difference. Populations of Lutjanus erythropterus in East Asia are inferred to be divided into two major groups: an eastern group, including populations of the western Pacific Ocean and the East Sea, and a South China Sea group, consisting of populations from northern Malaysia to South China. The results suggest that fishery management should reflect the genetic differentiation and diversity in East Asia. (c) 2006 International Council for the Exploration of the Sea. Published by Elsevier Ltd. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Western China is regarded as an assemblage of blocks or microplates. The India/Asia postcollisional kinematics of these blocks has attracted many geologists to pay attentions, especially on the geodynamics and intracontinental deformation of Tibetan and adjoining parts of central Asia. So far there are still many debates on the amount of continental shortening and extrusion within Western China blocks. Paleomagnetism plays a very important role in the paleogeographic reconstruction and depiction of kinematics of the blocks, however the unequilibrium of paleomagentic data obtained from Western China prevents paleomagnetists from studying the kinematics and intracontinental deformation on the Tibetan plateau and the central Asia. Moreover, shallower inclinations observed in the Cretaceous and Cenozoic terrestrial red sediments in central Asia makes it difficult to precisely estimate the northward convergence of Tibetan plateau and its adjacent areas since the onset of the Indian/Asian collision. In this thesis, detailed rock magnetic, chronological and paleomagnetic studies have been carried out on the Tuoyun Basin in the southwestern Tianshan to discuss the possible continental shortening and tectonic movements since the Cretaceous-Tertiary. Ar-Ar geochronological study has been conducted on the upper and lower basalt series from the Tuoyun Basin, yielding that the lower and upper basalt series were extruded during 115-113 Ma and 61.8-56.9 Ma, respectively. Both the age spectrum and inverse isochron show that the samples from the upper and lower basalt series have experienced no significant thermal events since extrusion of the baslts. Rock magnetic studies including temperature dependence of magnetization and susceptibility during a heating-cooling cycle from temperature up to 600 ℃ suggest that the baslt samples from the lower and upper basalt series are ferromagnetically predominant of magnetite and a subordinate hematite with a few sites of titanomagnetite. The predominant magnetic mineral of the intercalated red beds is magnetite and hematite. Anisotropy of magnetic susceptibility shows that both the baslts and the intercalated red beds are unlikely to have undergone significant strain due to compaction or tectonic stress since formation of the rocks. The stable characteristic remanent magnetization (ChRM) isolated from the most samples of the upper and lower basalt series and intercalated red beds, passes fold test at the 99% confidence level. Together with the geochronological results, we interpret the characteristic component as a primary magnetization acquired in the formation of rocks. Some sites from both the upper and lower basalts yielded shallower inclinations than the reference field computed from the Eurasia APW, we prefer to argue that these shallow inclinations might be related to geomagnetic secular variation, whereas the shallow inclination in the intercalated red beds is likely to be related to detrital remanent magnetization. Paleomagnetic results from the early Cretaceous-Paleogene basalts indicate that no significant N-S convergence has taken place between the Tuoyun Basin and the south margin of Siberia. Furthermore, the Cretaceous and Tertiary paleomagnetic results suggest that the Tuoyun Basin was subjected to a local clockwise rotation of 20°-30° with respect to Eurasia since the Paleocene time, which is probably subsequent to the Cenozoic northward compression of the Pamir arc.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Earlier studies on the distribution of geological environmental indicators in China revealed drastic changes from a zonal climate pattern (planetary-wave-dominant pattern) in the Paleogene to a monsoon-dominant one in the Neogene, which suggested an inception of the initial East-Asian summer monsoon. However, there are different views about the time and causes of the changes.Here, we attempt to compile a series of paleoenvironmental maps based on newly collected climate indicators from the literatures and chronologically constrained evidence of geological maps in order to re-examine the temporal and spatial evolution of climate belts in China during the Cenozoic with special emphasis on the changes of the arid belt. These indicators include mammalian fauna, coal, carbonate concretions, jarosite, salt, gypsum deposits and pollen assemblages etc, with chronological controls that we believe reliable. Pollen assemblages and mammalian fauna have been classified into three categories (arid, semi-arid/sub-humid, humid) to reflect the intensity of aridity/humidity. Salt, jarosite and gypsum deposits are classified as the arid indicators. Carbonate concretions and coal are classified into the semi-arid/sub-humid and humid one respectively. Paleoenvironmental maps at 8 time slices have been reconstructed. They are the Paleocene, Eocene, Oligocene, Miocene, Early Miocene, Middle Miocene, Late Miocene and Pliocene.And furthermore, we attempt to use IAP^AGCM to simulate the evolution of climate belts in emphasizing on the changes of the rain band, and compare the results with the paleoenvironmental maps in order to examine the causes of the drastic paleoenvironmental changes near the Oligocene/Miocene boundary. 36 sensitive numerical experiments are carried out using the IAP__AGCM to analyze the impacts of the uplift of the Himalayan-Tibetan complex, shrinkage of the Paratethys Sea, expansion of the South China Sea and the development of the polar ice sheets on rain band in China.The main conclusions are as follows:The obtained results essentially confirm the earlier conclusions about a zonal climate pattern in the Paleogene and a different pattern in the Neogene, and illustrate that a monsoon-dominant environmental pattern with inland aridity formed by the Early Miocene, which is temporally consist with the onset of eolian deposits in China.Cenozoic cooling and the formation of polar ice sheets are unlikely the main causes to the changes of environmental patterns mentioned above in China. But northern hemispheric cooling and the ice-sheets can intensify the Siberian High Pressure, and strengthen the winter monsoon circulations and enhance the aridity in the west part of China. These results support the earlier studies.Shrinkage of the Paratethys Sea and uplift of the Himalayan-Tibetan complex played important roles in strengthening the East Asian monsoon and induceing the above changes of environmental pattern, which is consistent with the earlier studies. Furthermore, "the monsoon-dominant pattern" appears when the Himalayan-Tibetan complex reaches to about 1000-2000 meters high and the Paratethys Sea retreats to the Turan Plate.4) Expansion of the South China Sea is another significant factor that drives the evolution of environmental patterns. We believe that the above three factors co-act and drive the change of the environmental patterns from a planetary-wave-dominant one to a monsoon-dominant one. However, the impacts of each factor vary by regions. The uplift mainly increases the humidity in Southwestern China and the aridity in northwestern country. The shrinkage mainly increases the humidity in Northern China and also enhances the aridity in the northwestern country. The expansion greatly increases the humidity in the south part of China.