东北南部早石炭世植物群研究

自作者（１９８７）在辽东本溪群下部发现Ｓｕｂｌｅｐｉｄｏｄｅｎｄｒｏｎ以来，又相继在吉南、辽南（范炳桓，１９９２）和辽西发现了Ｓｕｂ．ｓｐ．，Ｒｈｏｄｅａｈｓｉａｎｇｈｓｉａｎｇｅｎｓｉｓ等属于早石炭世的植物及维宪－纳缪尔Ａ期孢粉化石，从而证实东北南部普遍存在早石炭世地层。本文记述了产于上述层位的植物化石３０属７９种，并归纳为Ｓｕｂｌｅｐｉｄｏｄｅｎｄｒｏｎ－Ａｒｃｈａｅｏｃａｌａｍｉｔｅｓ－Ｌｉｏｐｔｅｒｉｓ组合（带）．东北南部早石炭世植物群中的一些属种，虽然显示了欧美植物群的特点，但其发生、演化又早于欧美植物群（分子），作者暂称为“东北南部早石炭世华夏植物群”。该植物群与东北北部安加拉植物群的界线，大致与槽台界线相吻合。     

U-Pb Zircon and Re-Os Molybdenite Geochronology of theW-Mo Mineralized Region of South Qinling,China, andtheir Tectonic Implications

A W-Mo mineralized region is located along the northern margin of the South Qinling tectonic belt of China. WMo mineralization occurs mainly in Cambrian–Ordovician clastic and carbonate rocks, and the ore bodies are structurally controlled by NW–SE-and NNE–SSW-striking faults. Evidence for magmatism in the area is widespread and is dominated by intermediate–felsic intrusives or apophyses, such as the Dongjiangkou, Yanzhiba, Lanbandeng, and Sihaiping granitic bodies. Quartz-vein-type mineralization and fault-controlled skarn-type mineralization dominate the ore systems, with additional enrichment in residual deposits. At present, there are few or insufficient studies on(1) the age of mineralization,(2) the relationship between intermediate–felsic granite and W-Mo mineralization,(3) the source of ore-forming materials,and(4) the metallogenic and tectonic setting of the mineralized area. In this paper, we present geochronology results for numerous intrusive granitic bodies in the South Qinling tectonic belt. U-Pb zircon geochronology of the Lanbandeng monzogranite and Wangjiaping biotite monzogranite yields ages of 222.7 ± 2.3 and 201.9 ± 1.8 Ma, respectively. In contrast to the Late Triassic age of the Lanbandeng monzogranite, the age of the newly discovered Wangjiaping biotite monzogranite places it at the Triassic–Jurassic boundary. Re-Os molybdenite geochronology on the Qipangou W-Mo deposit yielded a model age of 199.7 ± 3.9 Ma, indicating the deposit formed in the early Yanshanian period of the Early Jurassic. Granitoid intrusions in the mineralized area are characterized by composite granite bodies that crystallized at ca.240–190 Ma. While there were multiple stages of intrusion, most occurred at 210–220 Ma, with waning magmatic activity at 200–190 Ma. The Re-Os age of molybdenite in the region is ca. 200–190 Ma, which may represent a newly discovered period of W-Mo metallogenesis that occurred during the final stages of magmatism. The heat associated with this magmatism drove ore formation and might have provided additional ore-forming components for metallogenesis(represented by the Wangjiaping biotite monzogranite). Ore materials in the mineralized area were derived from mixed crustal and mantle sources. Enrichment of the region occurred during intracontinental orogenesis in the late Indosinian–Yanshanian, subsequent to the main Indosinian collision. At this time, the tectonic environment was dominated by extension and strike-slip motion.     

江西省峡江铀矿床两期印支期花岗岩的年代学、岩石地球化学和岩石成因——对华南印支期构造背景和产铀花岗岩成因的指示

位于江西省的峡江铀矿床为华南一个典型的花岗岩型铀矿床,铀矿体产在金滩花岗岩体中。野外地质调查和锆石U-Pb同位素定年工作表明金滩花岗岩体主要由两期的印支期花岗岩组成,其中含矿的等粒状二云母花岗岩形成于239±1Ma,而主体的斑状黑云母花岗岩则形成于226±2Ma。二云母花岗岩具有较高的SiO₂含量（74.09%~74.53%）和明显低的TiO₂、CaO和MgO含量,铝饱和指数为1.20~1.46,含有白云母和石榴子石等过铝质矿物,属于典型的强过铝S型花岗岩。斑状黑云母花岗岩的地球化学特征略微不同于二云母花岗岩,相对富集高场强元素和稀土元素,具有明显更低的Rb/Sr比值以及更小的Eu负异常,铝饱和指数变化为1.05~1.13,属于弱过铝到强过铝花岗岩。同位素组成上,两者都具有较低的ε_Nd（t）值（二云母花岗岩：-9.0~-8.8;斑状黑云母二长花岗岩：-9.8~-9.4）和古元古代的模式年龄（二云母花岗岩：1.73~1.75Ga;斑状黑云母二长花岗岩：1.77~1.80Ga）。地球化学和同位素特征表明金滩岩体中的这两期印支期花岗岩应该都为S型花岗岩。较高的Rb/Sr比值和较低的CaO/Na₂O比值表明二云母花岗岩主要由富粘土的泥质沉积岩部分熔融而来,而斑状黑云母二长花岗岩则主要由贫粘土的碎屑沉积岩部分熔融而来。金滩岩体中的两期印支期花岗岩分别对应于华南印支期同碰撞挤压和碰撞后伸展期的岩浆作用。二云母花岗岩含有更高的U含量,矿物学以及地球化学特征与华南其他的典型产铀花岗岩类似。对比研究表明,华南印支期产铀花岗岩的形成应与同碰撞期挤压背景下的泥质沉积岩的部分熔融有关。     

马兰冰芯记录的青藏高原中部现代升温变化特征

根据从可可西里地区马兰冰帽钻取的深102.07m冰芯记录中δ¹⁸O的年变化,恢复了青藏高原中部20世纪20年代以来的气候变化.研究表明,青藏高原中部的升温变化与北半球20世纪的升温变化的总体趋势一致,最暖阶段出现在50—80年代早期.期间也出现了几次明显的冷的波动,尤其80年代后期至90年代持续低温,可能与这一时段强盛的夏季风有关.这也表明20世纪末全球急剧升温变化的过程中,某些地区存在气候变冷的波动事件.     

ANALYSIS OF THE CHARACTERISTICS OF SUSTAINED TORRENTIAL RAINS IN JUNES DURING 1958-2000

Day-to-day precipitation data of Junes during the 43 years of 1958-2000 from stations to the south of Yangtze River are used to divide regions and run statistical analysis of sustained torrential rainfall processes. A preliminary analysis is then made based on it and the results show that June is the month in which torrential rains in the southern half of China take place frequently and sustained torrential rains occur at the same time in South China and the area to the south of Yangtze River. In addition, the analysis gives the basic features of sustained torrential rains of June in China and their interannual variability patterns, with the suggestion that the amount of these events increases significantly after the 1990s. Lastly, the sustained torrential rains occurring in Junes of 1994, 1998 and 2005 in the southern half of China are taken as examples in the research on the basic patterns and formation mechanisms of the evolution of double rain-bands during the rain season in South China and the area to the south of Yangtze River. The analysis shows that the large scale environment field in which sustained torrential rains occur is related to the stable sustaining of the South Asia High and upper level jet streams.     

南黄海崂山隆起中、古生界油气保存条件分析

崂山隆起位于南黄海盆地中部,海相中-古生界分布广泛且厚度大,其构造演化经历了加里东、海西、印支、燕山和喜山等多期构造运动,早期油气聚集可能在后期受到不同程度的破坏,因此,油气保存条件是崂山隆起油气勘探能否取得突破的关键因素。通过综合分析构造运动中抬升剥蚀作用和断裂作用与油气保存的关系,以及盖层条件与油气保存的关系,探讨崂山隆起内部油气保存条件的差异性以指导该区油气勘探。结果表明：崂山隆起呈差异性油气保存特点,位于崂山隆起中南部的高石稳定带是一个早期断裂不发育的弱变形区,后期构造运动改造破坏程度较弱,特别是下古生界具备较为优越的生储盖组合,构造多以断背斜和低幅宽缓背斜为主,发育多个大型圈闭,岩浆活动相对较弱,油气保存条件较为优越;而崂山隆起北部的青峰变形带断裂系统发育,地层褶皱变形强烈,单个圈闭规模较小,油气保存条件相对较差;高石稳定带中南部是进一步油气勘探和调查参数井钻探的重点目标区。     

藏南马扎拉金-锑矿床:成矿流体性质和成矿物质来源

马扎拉金-锑矿床是藏南巨型金-锑成矿带的重要组成部分,其矿床成因目前仍存在不同认识.通过主要矿石和蚀变围岩的岩相学、矿相学、流体包裹体和稳定同位素分析,探讨了马扎拉金-锑矿床的成矿流体性质、矿质迁移和沉淀机制.结果表明,马扎拉金-锑矿床成矿流体主要来自岩浆水,主成矿期流体为中温(约255℃)、低盐度(2.8%~3.5%NaCleqv)、富CO2流体,成矿压力约150 MPa,流体演化过程中的CO2与水的不混溶是造成矿质沉淀的主要原因,成矿金属主要来源于地层,特别是区域广泛分布的海相火山岩地层.     

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南秦岭古生代盆地演化中幕式流体过程及成岩成矿效应

从南秦岭古生代盆地构造-沉积演化出发,通过分析古生界不同层位流体成岩成矿事实与盆地发展演化之间的关系,探讨了南秦岭早古生代—泥盆纪演化时期多幕流体过程和成岩成矿效应。幕式流体成岩成矿最早可追溯到早寒武世,区域上从东到西形成了重要的碳硅质岩中重晶石/毒重石矿床及金、铂族元素矿化;早、中志留世继续发展,形成了钠长石岩、重晶石岩、铁碳酸盐岩、硅质岩与铅-锌、金矿床;中泥盆世为最强烈的一次热水沉积活动,其规模大、热水沉积产物多样,形成了泥盆系硅质岩-钠长石岩-重晶石岩-铁白云石岩中的铅锌(铜)矿床、铁白云石硅质岩中铅锌(铜)矿床以及钠长石角砾-铁白云石板岩中金-铜矿床。     

Critical Approach to Methods of Glacier Reconstruction in High Asia and Discussion of the Probability of a Qinghai-Xizang （Tibetan） Inland Ice

This overview discusses old and new results as to the controversy on the past glacier extension in High Asia, which has been debated for 35 years now. This paper makes an attempt to come closer to a solution. H.v. Wissmann's interpretation (1959) of a small-scale glaciation contrasts with M. Kuhle's reconstruction (1974) of a large-scale glaciation with a 2.4 million km2 extended Qinghai-Xizang (Tibetan) inland glaciation and a Himalaya-Karakorum icestream network. Both opinions find support but also contradiction in the International and Chinese literature (Academia Sinica). The solution of this question is of supraregional importance because of the subtropical position of the concerned areas. In case of large albedo-intensive ice surfaces, a global cooling would be the energetical consequence and, furthermore, a breakdown of the summer monsoon. The current and interglacial heat-low above the very effective heating panel of the Qinghai-Xizang (Tibetan) Plateau exceeding 4000 m, which gives rise to this monsoon circulation, would be replaced by the cold-high of an inland ice. In addition, the plate-tectonically created Pleistocene history of the uplift of High Asia — should the occasion arise up to beyond the snowline (ELA) —would attain a paleoclimatically great, perhaps global importance. In case of a heavy superimposed ice load, the question would come up as to the glacio-isostatic interruption of this primary uplift. The production of the loesses sedimentated in NE-China and their very probable glacial genesis as well as an eustatic lowering of the sea-level by 5 to 7 m in the maximum case of glaciation are immediately tied up with the question of glaciation we want to discuss. Not the least, the problems of biotopes of the sanctuary-centres of flora and fauna, i.e., interglacial re-settlement, are also dependent on it. On the basis of this Quaternary- geomorphological-glaciological connection, future contributions are requested on the past glaciation, the current and glacial permafrost table and periglacial development, the history of uplift, and the development of Ice Age lakes and loess, but also on the development of vegetation and fauna in High Asia.