Layer LJ3 of Linjiang stratigraphic section in Dongjiang River valley in the south of the Nanling Mountains is a set of red sandy sediments.Measured by thermoluminescence(TL) dating,it was found to be formed in MIS2-9,500 ± 800 yr to 19,600 ± 1,800 yr B.P.After analy-sis of the grain sizes of the 16 samples(LJ3-100 to LJ3-85) in this layer,it was discovered that(1) The contents of each grain group in dif-ferent samples are similar.(2) The values of Md,Mz,,Sk,and Kg vary from LJ3-100 to LJ3-85 in a narrow range.(3) The segments of each sample in the accumulative curves extend parallel with similar slopes.All the three aspects reveal the Aeolian characteristics of Layer LJ3.Therefore,it is thought that Layer LJ3 consists of red sandy sediments formed in MIS2 in the south of Nanling Mountain,which reflects the arid climate at that time. 相似文献
The LAMOST spectra and Kepler light curves are combined to investigate the detached eclipsing binary KIC 8098300,which shows the O'Connell effect caused by spot... 相似文献
Eddy covariance technique was used to measure carbon flux during two growing seasons in 2003 and 2004 over typical steppe in the Inner Mongolia Plateau, China. The results showed that there were two different CO2 flux diurnal patterns at the grassland ecosystem. One had a dual peak in diurnal course of CO2 fluxes with a depression of CO2 flux after noon, and the other had a single peak. In 2003, the maximum diurnal uptake and emitting value of CO2 were −7.4 and 5.4 g·m−2·d−1 respectively and both occurred in July. While in 2004, the maximum diurnal uptake and release of CO2 were −12.8 and 5.8 g·m−2·d−1 and occurred both in August. The grassland fixed 294.66 and 467.46 g CO2·m−2 in 2003 and 2004, and released 333.14 and 437.17 g CO2·m−2 in 2003 and 2004, respectively from May to September. Water availability and photosynthetic active radiation (PAR) are two important factors of controlling CO2 flux. Consecutive precipitation can cause reduction in the ability of ecosystem carbon exchange. Under favorable soil water conditions, daytime CO2 flux is dependent on PAR. CO2 flux, under soil water stress conditions, is obviously less than those under favorable soil water conditions, and there is a light saturation phenomena at PAR=1200 μmol·m−2·s−1. Soil respiration was temperature dependent when there was no soil water stress; otherwise, this response became accumulatively decoupled from soil temperature.