Abstract
Reflectance spectroscopy is rapid,inexpensive,and non-destructive and can provide important information about the mineralogy of rocks and sediments.We measured the reflectance spectroscopy of Miocene red clay deposits on the northeastern margin of the Tibetan Plateau,with the aim of developing a rapid methodology for detecting paleoclimatic changes.We obtained visible/near-infrared(VNIR)and short-wave infrared(SWIR)spectroscopy data from the red clay in the Jianzha Basin,and analyzed their relationship with independent paleoclimatic records,including mineral contents and environmental magnetic parameters.The results show that the VNIR parameters,including D500,D900,R500,and R900(where D and R represent the depth and reflectance of the absorption peaks around 500 and 900 nm,respectively)are temperature-sensitive and correlated with the magnetic susceptibility,frequency-dependent magnetic susceptibility,and the marine δ18O record.The results of frequency-domain analysis of the VNIR parameters show that they reflect climate change on orbital timescales.SWIR para-meters,such as AS 1400,D1 400/D 1900 and D1 900(where AS represents the asymmetry of the absorption peaks around 1400 nm),are correlated with the illite and montmorillonite content,and they are sensitive to the weathering intensity.The spectral parameters of the eolian red clay in the Jianzha Basin reflect regional climatic changes caused by the uplift of the Tibetan Plateau at～8.5 Ma and global climatic cooling at～7.2 Ma,and thus they are applicable as both regional and global pa-leoenvironmental indicators.
基金项目
Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0704 & 2019QZKK0101)
National Natural Science Foundation of China(42272221 & 41772167)
State Key Laboratory of Loess and Quaternary Geology(SKLLQG1905)
Central University Research Foundation,Chang'an University(300102272901)
维普
万方数据