Late Cenozoic magnetochronology and paleoenvironmental changes in the northern foreland basin of the Tian Shan Mountains

Abstract

[1] The folded Neogene deposits in the northern foreland basin of the Tian Shan Mountains provide important information about tectonic history and environmental changes of northwestern China. On the basis of lithostratigraphic and magnetostratigraphic evidence, we develop a new chronology for the previous studied Kuitun He section. Our palynological study on the late Miocene-Pliocene sediment of the Dushanzi section yields new information about vegetation and climate change during the period of 8.7-2.58 Ma. The results indicate that steppe taxa (Artemisia and Chenopodiaceae) were generally dominant in the studied areas between 8.7 and 2.58 Ma, implying that a dry climate has occurred in the inland basins of northwestern China at least since 8.7 Ma ago. Although the general climate pattern indicated by our palynological results displays to some extent of drought, a warm and humid phase occurred at 5.8-3.9 Ma ago. This climatic optimum is comparable with the other records from the Chinese Loess Plateau, central Japan, the Sub-Himalayan Zone, and the marine eustatic sea level rise, implying this seems to be, at least, a regional climatic optimum.

Late Cenozoic continuous aridification in the western Qaidam Basin: evidence from sporopollen records

“…10e). The eastern part of the Qaidam Basin shows some evidence of tectonic activity at about ∼ 14.7 Ma events; the NW part after Zheng et al, 2000;Chen et al, 2002;Wang et al, 2003;Sun et al, 2004Sun et al, , 824 2005Sun et al, , 2007Sun et al, , 2009Charreau et al, 2005;2006;Huang et al, 2006;Heermance et al, 2007Heermance et al, , 2008825 Sun and Zhang, 2008;Tang et al, 2011 and; the NE part after Li et al, 1997;826 Song et al, 2001a, b;Zhao et al, 2001;Fang et al, 2003Fang et al, , 2005aZheng et al, 827 2006;Lin et al, 2010;Wang et al, 2010;and Wang et al, 2011a, b), and (g) the presumed 828 paleoaltimetry history after An et al (2006). 829 , tectonic uplift events in (e) the Qaidam Basin (rectangle showing the tectonic events; the western basin after Chang et al, 2012; the eastern basin after Fang et al, 2007, andXiong, 2009) and (f) the northern Tibetan Plateau (rectangles showing the tectonic events; the NW part after Zheng et al, 2000;Chen et al, 2002;Wang et al, 2003;Sun et al, 2004Sun et al, , 2007Sun et al, , 2009Charreau et al, 2005Charreau et al, , 2006Huang et al, 2006;Heermance et al, 2007Heermance et al, , 2008Tang et al, 2011, and; the NE part after ...…”

“…H. Song et al, 2001;Y. G. Song et al, 2001;Chen et al, 2002;Fang et al, 2003Fang et al, , 2005aWang et al, 2003;Sun et al, 2004Sun et al, , 2007Sun et al, , 2009Charreau et al, 2005Charreau et al, , 2006Huang et al, 2006;Heermance et al, 2007Heermance et al, , 2008Lin et al, 2010;Wang et al, 2010;W. T. Wang et al, 2011;Tang et al, 2011;Zhang and Sun, 2011;Nie et al, 2013) (Fig.…”

Palynological evidence for the Mid-Miocene Climatic Optimum recorded in Cenozoic sediments of the Tian Shan Range, northwestern China

“…Among the various parameters used in reconstructing long-term terrestrial climate change, pollen analysis is one of the most useful because vegetation type shows a direct relation with climate change. In China, many recent studies have investigated the palynology of Neogene sediments (e.g., Wang, 1990;Wang et al, 1990;Hu and Sarjeant, 1992;Liu and Leopold, 1994;Ma et al, 1998Ma et al, , 2004Liang et al, 2003;Sun and Wang, 2005;Sun et al, 2007;Xu et al, 2008), however, the long-term paleoclimate records of the thick Cenozoic deposits of the northern foreland basins of the Tian Shan Range remain to be studied in detail.…”

Modern pollen and vegetation relationships in the Yili Basin, Xinjiang, NW China

“…Xinjiang is situated in the arid area of central Asia, which has been a hot spot for paleovegetation and paleoclimate research given its fragile ecology and sensitive response to climate change [6][7][8][9]. Modern pollen rain studies in Xinjiang have generated much attention over the past several decades [10][11][12][13][14][15][16][17][18].…”