کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4730941 1640392 2013 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Late early Oligocene East Asian summer monsoon in the NE Tibetan Plateau: Evidence from a palynological record from the Lanzhou Basin, China
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Late early Oligocene East Asian summer monsoon in the NE Tibetan Plateau: Evidence from a palynological record from the Lanzhou Basin, China
چکیده انگلیسی


• Sporomorphs in Lanzhou are used to study latest early Oligocene paleoclimate.
• Wet climate is linked with Asian summer monsoon initiation.
• Picea infers the high topography surrounding the basin.
• Later Oligocene Asian summer monsoon is linked with high Tibetan Plateau.

The latest Early Oligocene record from the Lanzhou Basin, northeast Tibetan Plateau, presents an opportunity to investigate early stage of the Asian monsoon patterns due to its special location. The record provides insights into the global zonal climate and the development of the non-zonal monsoon system. The study identifies possible links between factors governing the monsoonal patters and paleoaltimetry of the Tibetan Plateau. Sporomorphs results indicate the dominance of arboreal plants (both coniferous and broad-leaved) corresponding to a wetter environment, while xerophytes were rare. Based on the Coexistence Approach (CA), the climate of the Lanzhou Basin is likely to have been similar to that of present-day sites in Southeast China, i.e., characterized by relatively high precipitation and a warm climate. Both qualitative analysis of the sporomorph assemblages and quantitative calculations indicate that monsoons similar to those of the present daywere formed in East Asia and reached the Lanzhou region in inner Asia. High percentages of Picea, generally associated with the relatively high topography of the NE Tibetan Plateau, correlate well with the high paleoaltimetry of the main Tibetan Plateau during the Oligocene. Thus, the East Asian monsoon during this time can be closely linked to an uplifted Tibetan Plateau, following modeled relationships between the Tibetan Plateau and monsoon patterns. However, we believe such high precipitation may have mainly resulted from the orographic barrier, rather than being driven by zonal climate factors. Further investigation into the extent of, and controls on, the region of high precipitation should help clarify the role of these processes.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Asian Earth Sciences - Volume 75, 5 October 2013, Pages 46–57
نویسندگان
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