地质学

地质学

来源出版物：SCIENCE CHINA Earth Sciences，2015，58（2）: 183-194联系邮箱：LONG Hao，longhao@niglas.ac.cn

封面介绍：天然气水合物广泛发育于多年冻土区、大陆架边缘的深海沉积物和深湖泊沉积物中，是一种能量密度高的非常规高效清洁能源.由于天然气水合物性质不稳定且极易分解，在气候转暖情况下，多年冻土退化极易引起天然气水合物分解释放甲烷，将加剧北半球气候转暖和生态环境灾变.为了开发和利用多年冻土区天然气水合物新能源，揭示天然气水合物的气候环境效应，中国科学院寒区旱区环境与工程研究所吴青柏研究组通过实施钻探计划，寻找和发现青藏高原多年冻土区天然气水合物赋存证据，探讨多年冻土与天然气水合物赋存的关系.该研究将为青藏高原天然气水合物的开发和利用奠定基础，同时也为我国海洋天然气水合物未来开采提供理想的试验场所，对改变我国新能源结构和国家能源政策具有非常重要的意义.封面显示了2013年昆仑山垭口盆地天然气水合物450 m孔钻探现场.详见吴青柏等人文（p68）.

青藏高原昆仑山垭口盆地发现天然气水合物赋存的证据

吴青柏，蒋观利，张鹏，等

青藏高原多年冻土区是否存在天然气水合物一直是国内外广泛关注的问题，但一直没有确定的答案.通过钻探、地球物理测井以及气体地球化学研究，在昆仑山垭口盆地发现了天然气水合物赋存的证据.钻探发现250 m以下多个深度岩层存在大量气体释放异常，甲烷气体浓度为22%～32%，且具有天然气水合物分解间歇性释放的特征，这些气体释放层位具有显著的含天然气水合物特有的密度降低、侧向电阻率和声波波速的增大特征.同时多个深度上发现了与水合物分解产生甲烷密切相关的碳酸盐和黄铁矿等自生矿物.

昆仑山垭口盆地；多年冻土；天然气水合物；地球物理测井异常；气体释放

来源出版物：科学通报，2015，60（1）: 68-74联系邮箱：吴青柏，qbwu@lzb.ac.cn

封面介绍：14C and OSL chronologies suggest a significant timing offset on late Pleistocene lake highstands across the Tibetan Plateau and adjacent areas. This results largely from14C age underestimation when the sediments being dated were older than ～30 ka. The mega-palaeolake，traditionally assigned to MIS 3a based on14C dating，is likely older than ～80 ka based on OSL chronology. For more details see the research paper by LONG Hao et al. on pages 183-194.

Underestimated14C-based chronology of late Pleistocene high lake-level events over the Tibetan Plateau and adjacent areas： Evidence from the Qaidam Basin and Tengger Desert

LONG Hao，SHEN Ji

The palaeolake evolution across the Tibetan Plateau and adjacent areas has been extensively studied，but the timing of late Pleistocene lake highstands remains controversial. Robust dating of lacustrine deposits is of importance in resolving this issue. This paper presents14C or optically stimulated luminescence（OSL）age estimates from two sets of late Quaternary lacustrine sequences in the Qaidam Basin and Tengger Desert（northeastern Tibetan Plateau）. The updated dating results show:（1）the radiocarbon dating technique apparently underestimated the age of the strata of ＞30 ka BP in Qaidam Basin；（2）although OSL and14C dating agreed with each other for Holocene age samples in the Tengger Desert area，there was a significant offset in dating results of sediments older than ～30 ka BP，largely resulting from radiocarbon dating underestimation；（3）both cases imply that most of the published radiocarbon ages（e.g.，older than ～30 ka BP）should be treated with caution and perhaps its geological implication should be revaluated； and（4）the high lake events on the Tibetan Plateau and adjacent areas，traditionally assigned to MIS 3a based on14C dating，are likely older than ～80 ka based on OSL chronology.

Tibetan Plateau； lake highstand； lacustrine sediments；14C dating； OSL dating