Stability of fine-grained TT-OSL and post-IR IRSL signals from a c.1Ma sequence of aeolian and lacustrine deposits from the Nihewan Basin (northern China)
Stability of fine-grained TT-OSL and post-IR IRSL signals from a c.1Ma sequence of aeolian and lacustrine deposits from the Nihewan Basin (northern China)
复制标题
泥河湾盆地（中国北部）风成和湖泊沉积物 c.1Ma 序列的细粒度 TT-OSL 和后红外 IRSL 信号的稳定性
作者：
Liu Jinfeng;Murray Andrew S.;Buylaert Jan-Pieter;Jain Mayank;Chen Jie;Lu Yanchou
我们测试了细粒石英（4-11 μm）光激发发光（OSL）和热转移OSL（TT-OSL）以及细粒多矿物（4-11 μm）后红外IRSL的适用性中国泥河湾盆地小长梁考古剖面风成湖相沉积物样品测年的后IR IRSL或pIRIR信号;这些沉积物包括来自Jaramillo亚时（约1.0 Ma）的物质。在风成剖面上部，OSL和pIRIR 290年龄一致，表明上部8.8 m的沉积时间约为0.3 ~ 140 ka。发光年龄表明风成沉积物和较老的湖相沉积物之间存在一个主要的不连续性。在9.4 m处的这一间隙以下（即在湖相沉积物中），发现所有三个信号都处于野外饱和状态（埋藏剂量没有随深度进一步系统性增加），尽管TT-OSL信号（表观平均埋藏剂量~880戈伊）远低于实验室生长曲线上的饱和状态。这与pIRIR 290信号相反，pIRIR 290信号在现场以与实验室饱和度一致的水平饱和。这导致实测掩埋剂量的实际上限约为900戈伊（2D 0）。因此，对于TT-OSL和pIRIR 290信号，湖相沉积物定年的上限分别为<260 ka和约240 ka。这些结果有重大影响，这些信号的适当的未来应用。尽管我们所获得的湖相样品的年龄不一定准确，但这些年龄为研究当地的旧石器和地貌演化历史提供了除磁性地层学研究成果外的第一个长系列绝对年代学。
We tested the suitability of the fine‐grained quartz (4–11 μm) Optical Stimulated Luminescence (OSL) and thermally‐transferred OSL (TT‐OSL), and the fine‐grained polymineral (4–11 μm) post‐infrared IRSL (post‐IR IRSL or pIRIR) signals for dating samples from aeolian‐lacustrine deposits from the Xiaochangliang archaeological profile in the Nihewan Basin, China; these deposits include material from the Jaramillo subchron (c.1.0 Ma). In the upper aeolian section, the OSL and pIRIR290ages are consistent with each other, and show that the upper 8.8 m was deposited betweenc. 0.3 andc.140 ka. The luminescence ages indicate a major discontinuity in deposition between the aeolian and the older lacustrine deposits. Below this hiatus at 9.4 m (i.e. in the lacustrine sediments) all three signals are found to be in field saturation (no further systematic increase in burial dose with depth) despite the TT‐OSL signal (apparent mean burial dose ~880 Gy) being well below saturation on the laboratory growth curve. This is in contrast to the pIRIR290signal, which saturates in the field at a level consistent with laboratory saturation. This results in a practical upper limit to the measured burial dose of ~900 Gy (2D0). Thus for the TT‐OSL and pIRIR290signals, the upper limits for dating lacustrine deposits are <260 ka andc. 240 ka, respectively. These results have major implications for the appropriate future application of these signals. The ages of our lacustrine samples cannot be regarded as necessarily accurate ones; nevertheless, these ages provide the first long series absolute chronology for study of local palaeolithic and geomorphic evolution history aside from the magnetostratigraphical results available before this research.