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引用本文:白友良,吴润江,闫长红,王华伟,田坤.新疆孔雀河北岸72-51 ka BP湖相沉积物中粘土矿物特征.湖泊科学,2016,28(1):187-194. DOI:10.18307/2016.0122
BAI Youliang,WU Runjiang,YAN Changhong,WANG Huawei,TIAN Kun.Characteristics of the clay mineralogy from the 72-51 ka BP lake sediments in the northern margin of the Peacock River, Xinjiang. J. Lake Sci.2016,28(1):187-194. DOI:10.18307/2016.0122
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新疆孔雀河北岸72-51 ka BP湖相沉积物中粘土矿物特征
白友良, 吴润江, 闫长红, 王华伟, 田坤
西北核技术研究所, 西安 710024
摘要:
对新疆孔雀河北岸LX02剖面湖相沉积物开展光释光和粘土矿物样品X射线衍射分析,根据样品中的粘土矿物成分及质量分数对本区古气候演化进行了探讨.结果显示,该剖面湖相沉积自72 ka BP延续到51 ka BP.这期间,研究区粘土矿物以伊利石占绝对优势(56%~64%,平均为61%),其它粘土矿物有绿泥石(18%~26%,平均为22%)、高岭石(7%~12%,平均为8%)和伊/蒙混层(5%~15%,平均为9%),这与塔里木盆地粘土矿物组成颇为一致.具体来说,72.466.8 ka BP,伊利石和绿泥石含量之和较高,同时绿泥石含量较高,对于高岭石而言,除了一个样品外,其它样品的平均值较低,伊/蒙混层含量较低,指示该时段为冷干气候环境;66.856.1 ka BP,伊利石和绿泥石含量之和最低,同时绿泥石含量亦最低,高岭石、伊/蒙混层含量较高,指示该时段为暖湿气候环境;56.151.0 ka BP,伊利石和绿泥石含量之和增大,同时绿泥石含量亦增大,高岭石、伊/蒙混层含量较低,指示该时段为较冷干气候环境.这与孢粉植物群、地球化学元素含量及其主成分F1和粒度、色度及碳酸盐主成分F1'所反映的古气候特征及其变化一致,亦与柴达木盆地东部介形类丰度特征研究、柴达木盆地东部古湖泊高湖面光释光年代学研究、北京平原区有机碳同位素研究等结果吻合较好.研究表明塔里木盆地东部晚更新世气候仍以暖湿-冷干气候变化模式为主.
关键词:  晚更新世  粘土矿物  冷干-暖湿气候  孔雀河  新疆东部  湖相沉积物
DOI:10.18307/2016.0122
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Characteristics of the clay mineralogy from the 72-51 ka BP lake sediments in the northern margin of the Peacock River, Xinjiang
BAI Youliang, WU Runjiang, YAN Changhong, WANG Huawei, TIAN Kun
Northwest Institute of Nuclear Technology, Xi'an 710024, P. R. China
Abstract:
In this study, a 5.4-m-thick section of lake sediment was discovered from a LX02 profile in the northern margin of the Peacock River in Northwestern China. It is located at Tarim town (89°55'E, 40°40'N), Yuli County, eastern Xinjiang Province. From the upper to bottom, six ages of the Optically Stimulated Luminescence (OSL) samples were achieved, dated in 53.1±4.4 ka BP at 0.18 m, 56.1±3.2 ka BP at 1.19 m, 57.9±3.3 ka BP at 2.21 m, 60.5±4.0 ka BP at 3.10 m, 67.0±6.0 ka BP at 3.71 m, and 71.0±3.6 ka BP at 4.69 m, respectively. These suggest that this section spans Late-Pleistocene interval during 72-51 ka BP and establishes a reliable chronological framework for the LX02 section. Meanwhile, 18 clay mineral samples collected from the section were examined by the XRD. On the whole, illite is the dominant clay minerals, ranging from 56% to 64% in abundance with an average of 61%. Chlorite is the less dominant, fluctuating between 18% and 26% in abundance and averaging to 22%. Kaolinite ranged from 7% to 12% in content and had a mean of 8%. A mixed-layer illite-smectite ranged from 5% to 15% in content and had a mean of 9%. The presence of these clay minerals and their content variations were well consistent with those from the Tarim region. Specifically, the section is divided into three stages:in zones I (72.4-66.8 ka BP) the sum of illite and chlorite, chlorite was high in abundance while the Kaolinite and mixed-layer illite-smectite was usually low. In zones Ⅱ (66.8-56.1 ka BP) the sum of illite and chlorite, chlorite was low in abundance while the Kaolinite and mixed-layer illite-smectite was usually high. In zones Ⅲ (56.1-51.0 ka BP), the sum of illite and chlorite, chlorite was less high in abundance while the Kaolinite and mixed-layer illite-smectite was usually less low. These suggest that climate in the study area varied generally between dry-cold and humid-warm patterns during the Late-Pleistocene period. This mode of climate change in the study area is well correlated with the changes of weathering intensity revealed by pollen, geochemical elements. Principle components F1 and F1' of clay types are consistent well with Ostracoda abundance in the upper of Core Dacan1 located in the southeast Qaidam Basin, and also agreement with the luminescence chronology-based high lake levels of the paleolakes in eastern Qaidam Basin and with changes based on organic carbon isotopic characteristics from Beijing Plain. Nevertheless, the internal forcing mechanism for this mode of climate changes in the study area remains unclear up to now and deserves further investigation.
Key words:  Late-Pleistocene  clay mineral  dry-cold and humid-warm climate  Peacock River  eastern Xinjiang  lake sediments
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