224 resultados para Palaeoclimate
Resumo:
Southern China, especially Yunnan, has undergone high tectonic activity caused by the uplift of Himalayan Mountains during the Neogene, which led to a fast changing palaeogeography. Previous study shows that Southern China has been influenced by the Asian Monsoon since at least the Early Miocene. However, it is yet not well understood how intense the Miocene monsoon system was. In the present study, 63 fossil floras of 16 localities from Southern China are compiled and evaluated for obtaining available information concerning floristic composition, stratigraphic age, sedimentology, etc. Based on such reliable information, selected mega- and micro-floras have been analysed with the coexistence approach to obtain quantitative palaeoclimate data. Visualization of climate results in maps shows a distinct spatial differentiation in Southern China during the Miocene. Higher seasonalities of temperature and precipitation occur in the north and south parts of Southern China, respectively. During the Miocene, most regions of Southern China and Europe were both warm and humid. Central Eurasia was likely to be an arid center, which gradually spread westward and eastward. Our data provide information about Miocene climate patterns in Southern China and about the evolution of these patterns throughout the Miocene, and is also crucial to unravel and understand the climatic signals of global cooling and tectonic uplift.
Resumo:
A survey of the Neogene flora and vegetation pattern of the Pannonian domain based on 18 selected fossil plant assemblages is given. Flora and vegetation patterns are based on well-documented and studied fossil plant assemblages (macrofloras, primarily leaves). A general but slow cooling trend is definitely observable after the Early Miocene as reflected by both quantitative climate reconstructions and floristic change, i.e. decrease of diversity, slow disappearance of thermophilous and exotic elements, as well as decrease in the variety of vegetation types. A significant decline of coldest month temperatures (as compared to warmest month temperatures) must have played a defining role in forming flora and vegetation through the Neogene.