CAJ | 학술논문

通过对新疆罗布泊东南部阿奇克谷地西部LB剖面沉积物中的粒度组分及磁化率特征进行研究，综合沉积序列及岩性变化特征，分析了罗布泊阿奇克谷地第四系以来的沉积环境。结果表明，LB剖面湖相沉积物粒度组分主要集中于粉砂粒级，沉积物含有少量亚铁磁性矿物，超顺磁颗粒物含量较高。沉积物磁化率值的大小与粒度存在相关性，沉积物的中值粒径、粘土组分（小于2μm）及砂组分（大于63μm）含量与磁化率呈正相关，粉砂组分（2~63μm）含量与磁化率呈负相关。根据沉积物的粒度与磁化率组合的变化特征，结合岩性特征，将LB剖面划分为4个阶段：新近系末期(4.14~3.32m)气候以暖干为主；中更新世晚期(3.32~2.93m)粗颗粒呈现先降低后增加的趋势，水动力增强，磁化率的波动升高并保持较高水平，气候转向暖湿；晚更新世(2.93~1.44m)气候湿润，入湖的河道与水流量不断的发生改变，河流带入湖中的的外源物质的量不稳定，粒度和磁化率值波动变化较大，气候呈现暖干-暖湿的波动变化；全新世时期(1.44~0m)沉积物颗粒偏粗，磁化率值呈波动增加趋势，气候向冷湿转变，最终向干旱化发展。第四系以来沉积环境与古气候均有明显变化，本区气候环境经历了暖干-暖湿-暖干-冷湿的变迁过程，并最终向干旱趋势发展，体现为冷期湿润、暖期干旱的特征。
통과대신강라포박동남부아기극곡지서부LB부면침적물중적립도조분급자화솔특정진행연구，종합침적서렬급암성변화특정，분석료라포박아기극곡지제사계이래적침적배경。결과표명，LB부면호상침적물립도조분주요집중우분사립급，침적물함유소량아철자성광물，초순자과립물함량교고。침적물자화솔치적대소여립도존재상관성，침적물적중치립경、점토조분（소우2μm）급사조분（대우63μm）함량여자화솔정정상관，분사조분（2~63μm）함량여자화솔정부상관。근거침적물적립도여자화솔조합적변화특정，결합암성특정，장LB부면화분위4개계단：신근계말기(4.14~3.32m)기후이난간위주；중경신세만기(3.32~2.93m)조과립정현선강저후증가적추세，수동력증강，자화솔적파동승고병보지교고수평，기후전향난습；만경신세(2.93~1.44m)기후습윤，입호적하도여수류량불단적발생개변，하류대입호중적적외원물질적량불은정，립도화자화솔치파동변화교대，기후정현난간-난습적파동변화；전신세시기(1.44~0m)침적물과립편조，자화솔치정파동증가추세，기후향랭습전변，최종향간한화발전。제사계이래침적배경여고기후균유명현변화，본구기후배경경력료난간-난습-난간-랭습적변천과정，병최종향간한추세발전，체현위랭기습윤、난기간한적특정。
s:Based on a study of grain sizes and magnetic susceptibility of lake sediments along LB section in western Aqike depression of Lop Nur area, in combination with the sedimentary sequence and lithologic variations, the authors made a preliminary analysis of the sedimentary environment of the Aqike depression since Quaternary. The results show that the grain size component is mainly composed of silt of lake sediments along the LB section, magnetic minerals are composed of a small amount of ferromagnetic miner-als, with super-paramagnetic particles being abundant in sediments. The median grain size components, clay (<2μm) and sand (>63μm) are positively correlated to magnetic susceptibility, and fine sand (2~63μm) is negatively correlated to magnetic susceptibili- ty. According to the variation of grain size and magnetic susceptibility, combined with the lithologic characteristics, the authors divide the LB profile into four stages. In the Late Neogene (4.14~3.32m), the climate was warm and dry; in the late Pleistocene (3.32~2.93m), the coarse particles showed an increasing trend after decreasing, and hydrodynamic action tended to become strong, magneti-zation increased and remained at a high level, and the climate of Lop Nor began to change from warm-dry to warm-wet;in the mid-dle Pleistocene (2.93~1.44m), the climate was humid, the river and the water changed remarkably which resulted in the instability of some amounts of exogenous substances, grain-size and magnetic susceptibility values fluctuated widely, and the climate changes from warm-dry to warm-wet;in the Holocene (1.44~0m), coarse sand was increasing, and magnetic susceptibility values fluctuated and in-creased, the climate changes towards cold-wet and ultimately dry. Environment and paleoclimate have obviously changed since the Quaternary, suggesting a warm dry and wet climate fluctuation trend and ultimate development towards drought in this area, charac-terized by moistness in cold periods and drought in warm periods.