江苏沿江地区的空间结构与区域发展

江苏沿江地区的空间结构是距上海市距离和到最近长江港口距离２个因素综合作用的结果,据此可由江苏沿江地区人均ＧＤＰ的分布状态而反推出上海市市区的人均ＧＤＰ值。近１０年来该地区的长江南侧形成了一条新的发展轴线,表明苏南的区域空间结构已 基本成型。就港口与区域的关系而言,该地区的长江南北两侧,均遵循港口与区域与互动的协调发展模式。这一发展规律的揭示,对轴线尚未成型的江北区域的发展,具有重要的指导意义。在此     

Tidal Breakup of Comets

In the context of the survival of periodic comets of different origins, rotational breakup and tidal disruption could be important, especially of the short period comets injected from the Kuiper belt. This is because long-period comets from the distant Oort cloud tend to be subject to thermal stress and volatile 'explosion' far more severely. A simple calculation using the Öpik method of random planetary close encounters was performed to estimate the probability of tidal disruption of comets and scattered Kuiper belt objects (SKBOs) during their orbital migration. It was found that a large fraction of the short period comets and SKBOs might have been internally fragmented by single or multiple close encounters with the outer planets.     

幕阜山矿集区黄柏山锂铌钽矿床地质特征及找矿方向

江南造山带中段幕阜山稀有金属矿集区是我国东部重要的锂铌钽资源基地, 区域锂资源主要集中于锂辉石伟晶岩中。但此类伟晶岩常受到岩浆出溶热液的叠加作用, 导致锂不同程度的流失, 因此新鲜锂辉石伟晶岩的产出条件与精准定位, 成为区域成矿理论研究与锂资源勘查的突破重点。笔者研究团队近年来在幕阜山地区新发现的黄柏山锂铌钽矿床, 产出了区域少有的大规模新鲜锂辉石伟晶岩脉。本次研究在黄柏山矿床已开展的化探、探槽、钻探等勘查工作基础上, 系统总结了矿床的地质条件, 精确厘定其成矿时代, 初步建立了仁里-黄柏山矿田成矿模型, 并进一步指出区域找矿方向。黄柏山矿床位于幕阜山岩体西南缘, 矿床内伟晶岩总体沿片岩片理产出, 其类型主要为(白云母)钠长石伟晶岩和锂辉石钠长石伟晶岩, 稀有金属矿化组合为Be-Nb-Ta-Li, 稀有金属矿物主要为绿柱石、铌钽铁矿和锂辉石。矿床内锂辉石多为新鲜无蚀变(＞96%), 少数晶体边缘具弱蚀变或锂辉石+石英蠕虫状共生结构, 为岩浆演化晚阶段流体出溶导致的弱酸性交代所致。三种类型锂辉石的Li2O为7.72%~7.82%, 基本未发生锂的流失, 这与区域构造交汇导致容矿空间封闭性弱, 岩浆演化出溶热液第一时间运移扩散有关。黄柏山矿床稀有金属成矿作用发生在早白垩世(133.0±1.5Ma), 与幕阜山矿集区二云母花岗岩成矿阶段时限(135.8~133.0Ma)一致。本次工作通过对仁里-黄柏山矿田伟晶岩地表类型分带的重新厘定, 结合区域已有的成矿母岩及伟晶岩垂向分带研究成果, 提出黄柏山矿床、仁里矿床、深部成矿母岩三者从西至东呈现出由高至低的三维空间分布特征, 初步建立矿田"体中体"模型。该模型及稀有金属成矿作用特点显示, 矿田西南部冷家溪群与幕阜山岩体接触带区域, 尤其是高地形地区, 仍具有锂找矿潜力。     

即墨地区莱阳群底部止凤庄组地质特征及其碎屑锆石LA-ICP-MS U-Pb年龄地质意义

为了了解盆地沉积初期的物源特征,对位于胶莱盆地东缘即墨地区早白垩世莱阳群止凤庄组沉积特征、物质组成及碎屑锆石进行了U-Pb同位素测年研究。野外调查表明,止凤庄组为一套陆源碎屑沉积,具有近源沉积的特点。南泊一带止凤庄组底部碎屑岩碎屑锆石LA-ICP-MS U-Pb年龄介于233~734 Ma,年龄分布于5个区间,呈现明显的幕式特征,至少记录了2次重要的构造热事件。侵入于止凤庄组石英二长岩的锆石U-Pb加权平均年龄为(123.50±0.95)Ma,限定了止凤庄组地层沉积上限年龄为123.50 Ma。综合分析认为,止凤庄组物源主要来自苏鲁造山带,部分来自扬子板块。这有助于了解胶莱盆地沉积初期其物源区苏鲁造山带的地体情况。     

兰天武地区现今大地垂直形变场演化与地壳运动特征

用分段线性速率整体动态平差法处理了兰天武地区２０多年来的多期水准资料，分析了该区现今大地垂直形变场演化与地壳运动特征。研究结果表明：该区垂直形变七十年代曾表现出山间盆地大幅度上升的强烈逆继承性运动；八十年代华家岭等两北部山地上升、东南部盆地下沉的继承性运动增强；而目前基本恢复了正常的继承性运动状态。进一步分析认为：强烈逆继承性运动和继承性运动增强是区域应力场趋于强化的标志；正常继承性运动的恢复可能是应力场调整的结果。     

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Kuiper带小天体动力演化

Kuiper带是指太阳系内位于离太阳 30～ 50AU一个区域。 1 992年该区域陆续发现了一群半径在几十到几百公里的小天体。这些小天体在Kuiper带的分布是极其不均匀的。Kuiper带小天体的发现对人们认识太阳系的形成与演化有重要的意义。本文回顾了近年来国际上在Kuiper带小天体动力演化方面的研究 ,着重分析了目前国际上几种用以解释其非均匀分布的动力学机制 ,并提出目前该领域的一些尚未解决的问题。     

Differential uplift between Beihuaiyang and Dabie orogenic belt

Isotope dating, hornblende geobarometer, fission-track analysis and fluid inclusion homogeneous temperature analysis have been applied to Caledonian, Variscan and Yenshan plutons in Bei Huaiyang (BHY) and Dabie orogenic belt (DOB), and the emplaced depths and ages of these plutons have been obtained in order to obtain differential uplift time and uplift heights between BHY and DOB since late Paleozoic era. BHY had experienced three stages of uplift (C1-C2, T-J2, J3-K1) and its total uplift height is about 10 km, but, DOB had only experienced two stages of uplift (T-J2, J3-K1) and its maximum uplift height is more than 15 km. BHY uplift occurred mainly before the mid-Jurassic (about 150 Ma), but DOB uplift took place after the mid-Jurassic (about 150 Ma).     

Global temperature and monsoon activity

In this paper an attempt has been made to search a new parameter for the prediction of the Indian summer monsoon rainfall. For this purpose the relationship of the global surface-air temperature of four standard seasons viz., Winter (December-January-February), Spring (March-April-May), Summer (June-July-August), Autumn (September-October-November) with the Indian summer monsoon rainfall has been carried out. The same analysis is also carried out with surface-air temperature anomalies within the tropical belt (30°S to 30°N) and Indian summer monsoon rainfall. For the present study data for 30 years period from 1958 to 1988 have been used. The analysis reveals that there is a strong inverse relationship between the monsoon activity and the tropical belt temperature.     

西藏冈底斯成矿带矿化蚀变提取与成矿分析——以尼玛县帮勒地区为例

冈底斯成矿带是我国极具找矿潜力的地带,但受自然条件限制,该地带矿产资源开发程度普遍偏低。选取冈底斯成矿带北部尼玛县帮勒地区为研究区,以Landsat-8OLI数据为主要信息源,采用主成分分析法提取研究区铁染和羟基矿化蚀变信息。在GIS平台上,将提取的蚀变信息结合研究区现有地质、化探、矿产等资料进行综合分析,依据成矿理论,圈定2个成矿远景区。经野外验证,文中获取的矿化蚀变信息分布状况与已知矿点和已探明蚀变带的空间一致性高。矿化蚀变带的探明能够为区域矿产资源开发与勘查提供帮助。