长江源区新生代火山岩的年代学研究

长江源区的火山岩包含了青藏高原北部新生代火山岩形成及演化的全部信息，其年代学研究对查明青藏高原北部新生代火山活动时空演化具有重要意义。通过K—Ar同位素年代学研究，将长江源区新生代的火山活动划分为3期：第Ⅰ期(40．1-35．1Ma)火山喷发较弱，形成小范围分布的细粒安粗岩和斑状粗面岩；第Ⅱ期(26．5～17．6Ma)火山喷溢最为强烈，形成大面积厚层黑色气孔状安粗岩；第Ⅲ期(5．5-4．61Ma)由潜火山作用形成球粒状、斑状粗面岩岩丘。长江源区3个期次的火山喷发与青藏高原北部火山活动的阶段性相对应。长江源区新生代火山岩的演化特征为：从早到晚，岩石系列由高钾钙碱性系列→钾玄岩系列演化；岩性由安粗岩→粗面岩演化。     

塔北隆起-库车坳陷区中新生代基底-盖层构造变形机理

利用三维建模软件获取了塔北隆起-库车坳陷区现今及不同时期基底构造格局，为基底构造分析提供了新的技术方法。研究表明，三叠纪-古近纪，塔里木盆地北部块体的基底构造基本处于稳定状态，基底-盖层构造变形不明显；新近纪，克拉苏背斜带以北的塔里木盆地基底明显向天山倾斜，库车基底俯冲变形导致基底转折带逐渐向南迁移，库车前陆盆地形成；第四纪时期，库车-拜城盆地的基底整体向天山下倾斜，基底构造的强转折带迁移到塔北隆起带；新近纪以来库车坳陷的基底转折期与塔北隆起盖层的负反转构造形成期在时间上一致，在空间上，库车坳陷的基底在强烈沉降俯冲的同时，相邻塔北隆起的基底相对隆起，形成库车新生代前陆盆地的前隆；库车前陆冲断带的形成是在库车基底斜坡上伴随天山的推覆而形成的；塔北隆起为库车前陆盆地的前隆，基底俯冲变形及其转折带迁移导致塔北隆起盖层负反转构造的形成。     

Geochemical characteristics of Cenozoic high-K igneous rocks from Liuhe-Xiangduo area, eastern Tibet

The major elements, trace elements and Nd-Sr isotopic composition of Cenozoic high-K igneous rocks and mafic deep-derived enclaves from the Liuhe-Xiangduo area, eastern Tibet, indicate the high-K igneous rocks are characterized as being enriched in Ca (CaO= 1.20% - 8.80% ), alkali (Na2O K2O= 3.47% - 10.65% ), especially K (K2O up to 5.96% ) and depleted in Ti (TiO2= 0.27% - 1.50% ). Their REE contents are very high (REE= 91.29 - 231.11 μg/g). Their REE distribution patterns are of the right-inclined type, characterized by intense LREE enrichment [(La/Yb)N= 7.44 - 15.73 ]. The rocks are distinctly enriched in Rb, Sr and Ba ( 46.3 -316 μg/g, 349-1220 μg/g and 386-2394 μg/g, respectively), high in U and Th ( 1.17 - 8.10 μg/g and 2.58 - 27.0 μg/g, respectively), moderate in Zr and Hf ( 87.5 -241 μg/g and 2.83 - 7.52 μg/g, respectively), and depleted in Nb and Ta ( 4.81 - 16.8 μg/g and 0.332 - 1.04 μg/g, respectively). In the primitive mantle-normalized incompatible element spidergram, U, K, Sr and Hf show positive anomalies, whereas Th, Nb, Ta, P, and Ti show negative anomalies. The rocks are strongly depleted in Cr and Ni ( 21.4 -1470 μg/g and 7.79 -562 μg/g, respectively), and their transition element distribution curves are obviously of type-W. The ( 87 Sr/ 86 Sr)i ratios range from 0.704184 to 0.707539 ; ( 143 Nd / 144 Nd)i from 0.512265 to 0.512564 ; and ε Nd (t) from -6.3 to -0.4 . These geochemical features might suggest that the potential source of the high-K igneous rocks in the Liuhe-Xiangduo area is similar to the EM2, which may be similar to the material enriched K that is located under the crust-mantle mixed layer. The mafic deep-derived enclaves in the high-K igneous rocks belong to chance xenoliths. Their ( 87 Sr/ 86 Sr)i ratios range from 0.706314 to 0.707198 ; ( 143 Nd / 144 Nd)i from 0.512947 to 0.513046 ; and ε Nd (t) from 7.0 to 9.0 . These geochemical features might indicate that the enclaves probably came from the depleted mantle. The P-T conditions of the enclaves also showed that the enclaves are middle-lower crust metamorphic rocks, which were accidentally captured at 20-50 km level by rapidly entrained high-K magma, whose source is over 50 km in depth.     

川西鲜水河断裂带晚新生代剪切变形40Ar/39Ar测年及其构造意义

基于野外地质调查、构造测量和白云母、黑云母、钾长石等矿物的⁴⁰Ar/³⁹Ar阶段升温测年分析, 获得了鲜水河断裂带新近纪左旋剪切变形冷却年龄. 观察和测试结果记录了剪切带两次热事件. 早期热事件(12~10 Ma)对应于鲜水河主干断裂西侧折多山中细粒花岗岩体从高温(>700℃)到中低温(<350℃)的快速冷却; 晚期热事件(5~3.5 Ma)对应于鲜水河主干断裂东侧细粒花岗岩体或岩脉的快速冷却. 测年结果为青藏高原东南缘川滇地块晚新生代向东构造挤出提供了重要的热年代学制约.     

塔里木北缘晚新生代断裂活动的年代学

运用热释光测试技术，从断层泥中提取时间信息，得到塔里木北缘四条重要断裂晚新生代活动年龄：①辛格尔断裂：(4．06t0．33)万a；②兴地断裂：(4．72t0．37)-(9．61t0．75)万a；③库车断裂(11．89t0．95)万a；④柯坪-沙井子断裂：(19．79t1．52)万a。年龄数据说明，新生代印藏碰撞对塔北地区远距离影响，这种影响不仅造成新断裂的产生，而且造成老断层的重新活化。同时，晚新生代断裂活动年龄的获得，对研究天山地区盆山耦合机制具有一定意义。     

Fission Track Dating of Authigenic Quartz in Red Weathering Crusts of Carbonate Rocks in Guizhou Province

The Cenozoic evolution history of Guizhou Province, which is located on the southeastern flank of the Qinghai-Tibet Plateau, is unclear because of the lack of sedimentation records. The red weathering crusts widespread on the Yunnan-Guizhou Plateau may bear critical information about their evolution history. This work firstly determined the ages of four red weathering crusts in eastern, central and northern Guizhou. The material used in fission track dating is well-crystallized quartz occurring in many in-situ weathering crusts of carbonate rocks. The results showed that the fission track ages of quartz vary over a wide range from 1 to 25 Ma in the four profiles, significantly younger than the ages of the Triassic and Cambrian parent rocks. In combination with the evolution history of the regional geology during the period from 25 to 1 Ma, the ages of quartz can exclude the possibility that the origin of quartz has nothing to do with primary clastic minerals in parent rocks, authigenesis during diagenesi     

东营凹陷新生代火山岩及其与盆地演化-油藏的关系

用地质学、岩石化学、地球化学方法研究了东营凹陷新生代火山岩的分布、产状、岩相及岩石种属、碱度、钾钠类型、岩浆成因与盆地演化、油藏的关系．研究表明：火山喷发既有陆上喷发，也有水下喷发，均以溢流为主；火山岩既有拉斑玄武岩，也有碱性玄武岩，类型为钾质略高的普通型和钾质不高的钾质型；火山岩由幔源原始岩浆在上地幔、地壳岩浆房中演化后喷出地表形成，是盆地强烈拉张下陷和生油层堆积最盛时期的产物；岩浆活动为生油层的熟化和石油的生成提供了热能，火山岩中部分是石油的良好储集层，部分是良好的屏蔽层，与油藏有着密切的关系     

准噶尔盆地晚新生代地理环境演变

准噶尔盆地是我国西北干旱区五大自然地理单元之一。本文主要论述了该盆地晚新生代以来干旱环境的形成演变，阐述了现代干旱环境的主要特点与发展趋势。指出干旱环境由来已久，具有继承性与持久性。     

青藏高原晚新生代以来地球化学演化与古气候变迁刍议

青藏高原晚新生代以来地球化学演化与古气候变迁刍议余素华，文启忠（中国科学院广州地球化学研究所．广州５１０６４０）关键词古气候，地球化学演化，晚新生代以来，青藏高原晚新生代以来，在更新世初期，随着青藏高原的强烈上升，改变了大气环流形式，季风开始占主导优...