Cenozoic Sedimentary Sequence in the Kumkal Basin, Xinjiang and New Evidence for the Late Quaternary Uplift of the Qinghai-Tibetan Plateau

1. IntroductionThe Qinghai-Tibetan Plateau is an importantregion for the study of the global change andstructural evolution history). The in-depth knowledgeon its uplift process is the ke}' to understand theformation and development of temporary ph}'sicalenvironment of China or even East Asia. Therefore.a large quantity of researchers have given muchmore attention on this field (Burbank et al.. l982;Fang Xiaornin et al.. 1995f Ruddoman. ]997f AnZhisheng et al.. 1998). The macroscopic e\'o…     

藏北高原双湖地区中侏罗统海相油页岩生物标志化合物分布特征及其意义

重点报道了藏北双湖地区中侏罗统海相油页岩的生物标志化合物特征,首次在该层位油页岩中检出丰富的正烷烃、类异戊二烯烷烃、萜类化合物及甾类化合物。正烷烃图谱呈单峰形,nC₁₅、nC₁₆或nC₁₇为主峰碳,轻烃组份占有绝对优势,OEP值 0.93～ 1.0 1,无明显的奇偶碳数优势分布;Pr/Ph值为 0.77～ 1.5 9,在剖面序列中呈波动分布,显示弱植烷优势或姥鲛烷优势;藿烷以C₃₀ 占优势,萜烷相对丰度五环三萜烷 >三环萜烷 >四环萜烷;规则甾烷∑ (C₂₇+C₂₈) >∑C₂₉,∑C₂₇/∑C₂₉值为 0.79～ 1.2 0,在剖面序列中下部C₂₇甾烷略占优势,上部C₂₉甾烷略占优势,重排甾烷C₂₇/规则甾烷C₂₇值为 0.5 1～ 3.6 3,在剖面序列中具有显著的波动性,同时检出了少量孕甾烷和 4-甲基甾烷。有机质母质构成中,既有丰富的藻类等低等水生生物,可能还有一定比例陆生高等植物输入混合的特点。油页岩处于成熟阶段,整个油页岩剖面序列具有一致的热演化程度。剖面中部油页岩具有极高的原始生产力,氧化-还原条件也是控制油页岩TOC和沥青“A”含量在剖面垂向变化的重要因素.     

绿片岩力学性质的实验研究

绿片岩的力学实验表明 ,在围压 45 0MPa条件下 ,岩石约于 45 0℃开始塑性变形。温度升至 5 5 0℃时变形加剧 ,原来直径为 10mm、高 2 0mm的均匀圆柱体变成直径为 10 8mm、高 17 4mm、中部变粗的不规则柱体。这一结果为解释青藏高原的地壳加厚提供了一定的实验依据     

Relationship between δD and δ18O in precipitation on north and south of the Tibetan Plateau and moisture recycling

The local meteoric water line (MWL) has been established from north to south of the Tibetan Plateau based on the measured results of δD and δ¹⁸O in precipitation and river water, and the relationship between MWL and moisture origins discussed. The spatial and seasonal variations ofd in precipitation and river water on the Tibetan Plateau have been studied. Results show that the spatial and seasonal variations ofd between north and south of the Tanggula Mountains are related to different moisture origins and water recycling.     

青藏高原OLR的气候特征及其对北半球大气环流的影响

利用１９７４－１９９０年青藏高原地区地－气系统月平均射出长波辐射资料，采用ＥＯＦ方法分析了前３个特征向量场，得到了青藏高原地区地－气系统射出长波辐射的几种异常形式，阐述了它们的天气气候特征，并对不同气候区的持续 及其与北半球大气环流的关系作了研究。     

In situ formation of welded tuff-like textures in the carapace of a voluminous silicic lava flow,Owyhee County,SW Idaho

 The Badlands rhyolite, on the Owyhee Plateau of southwestern Idaho, can be demonstrated to be a large lava flow on the basis of its geometry of large and small flow lobes, its well-exposed near-vent features, and its response to pre-existing topography. However, samples of the dense upper vitrophyre of the unit reveal a range of annealed fragmental textures, including material which closely resembles the compressed, welded glass shards which are characteristic of ignimbrites. Formation of these tuff-like textures involved processes probably common to emplacement of most silicic lava flow units. Decompression upon extrusion causes inflation of pumice at the surface of the lava flow; some of this pumice is subsequently comminuted, producing loose bubble-wall shards, bits of pumice, chips of dense glass, and fragments of phenocrysts. This debris sifts down around loose blocks and into open fractures deeper in the flow, where it can be reheated, compressed, and annealed to varying degrees. The end result is a dense vitrophyre layer (beneath the true upper, non-welded carapace breccia) which can be extremely texturally heterogeneous, with areas of flow-foliated lava occurring very near lava which in many aspects looks like welded ignimbrite, complete with flattened pumices. Identical textures in other silicic units have been cited by previous workers as evidence that those units erupted as pyroclastic flows which then underwent sufficient rheomorphism to create a flow-foliated rock which otherwise appears to be lava. The textures described herein indicate that lava flows can come to mimic rheomorphic ignimbrites, at least at scales ranging from thin sections to outcrops. Voluminous silicic units with scattered fragmental textures, but with otherwise lava-like features, are probably true effusive lava flows. Received: January 30, 1995 / Accepted: January 22, 1996     

Seismic anisotropy beneath Southern Tibet

ＳｅｉｓｍｉｃａｎｉｓｏｔｒｏｐｙｂｅｎｅａｔｈＳｏｕｔｈｅｒｎＴｉｂｅｔＱＩＮＧ－ＴＩＡＮＬＵＩ（吕庆田），ＫＡＩ－ＹＩＭＡ（马开义），ＭＥＩＪＩＡＮＧ＇（姜枚），Ａ．ＨｉｒｎａｎｄＡ．Ｎｅｒｃｅｓｓｉａｎ（ＩｎｓｔｉｔｕｔｅｏｆＭｉｎｅｒａｌＤｅ...     

ON THE LAYER-ZONE OF ALPINE MEADOW ON THEQINGHAI-TIBETAN PLATEAU

RuleofzonalityisoneofthedassicaltheonesinGeOgraphy.Thedifferentiationofzonalityfromaz0nalityindicatesthedevel0pmentofpeople'Scoguhveabilitiestonaturallaw.Longitudinal,latitudinalandaltitudinalzonalitiesbelongt0idealconcePts,however,theywerefavorablet0theformationoftheconcePtofthIeedimensi0nalzonality.UPt0n0wtherehavebeenmanydifferentideasonzonality.ForexamPle,inanarr0wsense,zonality0ulyreferst0thelatitudinalzonality,namely,thequatityofheatorairtemPeraturegraduallyChangs,whichresultsinthezo…     

800KaB．P．来西藏“一江两河”中游地区的气候与西南季风变化

西藏“一江两河”中游地区风成地层沉积时代、沉积相和磁化率等研究结果表明，早在８００ＫａＢ．Ｐ．前西南季风就已存在，受全球气候波动和青藏高原隆起的影响，其盛行衰变与东南季风具有较好的一致性，主要表现为本区地层所记录的气候变化信息不如东南季风区详细；而且西南季风因高原屏障作用给本区带来的降水愈来愈少，气候明显地向干冷化发展。     

青藏高原东北部古喀斯特过程与环境

本文介绍了青藏高原东北部地区的古喀斯特现象，并对相关沉积进行了化学成、粘土矿物的Ｘ－射线衍射以及石英砂表面结构等气候代用指标的分析。分析结果一致，指示了温暖湿润的亚热带气候条件。重结晶方解石的裂变径迹测年结果表明，该地区古喀斯特发育于中中新世。