A Study of the Sedimentary Environment of the Xiaoxi Formation in NE of Guizhou,China

The Xiaoxi Formation is well developed in two sections (Heishui, Yinjiang and Wuguxi, Shiqian), NE of Guizhou, China.This formation is composed of the sandstones, siltstones and mudstones, and preserved with the depostional structures and trace fossils. This paper focuses on the study of the sedimentary environment of the Xiaoxi Formation based on the materials from these sections. Five ichospecies are identified from two sections, including Palaeophycus isp., Rusophycus isp., Planolites isp., Gordia isp. and Phycodes isp. These trace fossils belong to the Cruziana ichofacies, Based on the depositonal structures, the ichofaces and the result of particle size analysis, the sedimentary environment of the Xiaoxi Formation of Silurian in NE of Guizhou is nearshore zone with a relativealy and stable environment under the average low tide line.     

漠河盆地中侏罗统沉积特征研究及其地质意义

从露头、岩芯、测井、薄片鉴定等方面出发对漠河盆地中侏罗统沉积特征进行了详细的研究。中侏罗世漠河盆地主要发育冲积扇、扇三角洲和湖泊相沉积,其中冲积扇相可划分为扇根、扇中、扇端3个亚相;扇三角洲相可划分为扇三角洲平原、扇三角洲前缘、前扇三角洲3个亚相;湖泊相可划分为滨湖、浅湖、半深湖3个亚相。中侏罗世漠河盆地从南向北盆地水体加深,从绣峰组到开库康组,具有冲积扇—扇三角洲平原—扇三角洲前缘—滨浅湖—半深湖的变化趋势。从生储盖条件分析,漠河盆地具有较好的油气勘探前景。     

会泽黄草岭磷矿地质特征及成矿浅析

会泽县黄草岭磷矿含矿层位为下寒武统渔户村组中谊村段（∈1yz）,胶磷矿由砂屑、砾屑、鲕粒组成,孔隙一基底胶结,多伴铁泥质胶结,颗粒形态次圆、不规则状,细、粗颗粒含量不均;沉积环境处于古陆边缘浅海地域,矿物质来源主要取决于古陆风化淋滤作用.     

兰坪县金顶铅锌矿床地质特征及成因分析

兰坪县金顶铅锌矿体主要赋存在一个封闭的构造体系当中,早期经过成岩成矿阶段的初步富集,晚期弯窿构造形成过程中矿物质再次富集,形成了一个陆（湖）相热水沉积超大型矿床。     

济南千佛山地区沉积地层特征地质构造演化及古地理

济南千佛山及其周边地区的早古生代地层在我国北方极具代表性,该文在结合前人的大量研究总结和野外地质调查基础上,对千佛山地区的岩石地层、沉积相、层序地层和区内存在的重要地质构造界面进行了详细的总结;同时,结合该区在大地构造单元中所处的位置对其地质构造演化和古地理进行了系统的总结。     

Contributions of zircon U–Pb geochronology to understanding the volcanic and sedimentary history of some Purāna basins,India

In this century, U–Pb ages of magmatic and detrital zircons, together with a few less accurate but fairly robust ages determined on monazite and baddeleyite, in the Purāna successions in India have established a few firm timelines that constrain the opening, closure, inversion, and provenance of the Purāna basins. The Cuddapah basin opened shortly before ca. 1900 Ma, the Vindhyan basin opened before ca. 1630 Ma, the Khariar basin likely opened ca. 1500 Ma, and the Chhattisgarh basin opened ca. 1400 Ma. The Marwar basin opened after ca. 750 Ma. The Chhattisgarh basin began to invert at ca. 1000 Ma and closed shortly thereafter. The Indravati and the Vindhyan basins closed ca. 1000 Ma. There are no other defensible geochronologic data to adequately constrain the opening and closure of other Purāna basins (e.g., Kaladgi, Badami, Bhima, Kurnool, Mallampalli, Albaka, Ampani, Sabari, and Kolhan). Neither the fossil record nor the biostratigraphy of these basins necessarily correspond to the chronology determined through radiometric measurements.The discovery of ca. 1000 Ma volcanic events in the Indravati and Chhattisgarh basins adds to the growing list of ca. 1000 Ma thermal disturbances in the Indian shield. Most of these events were likely the far field effects of the final assembly of Rodinia.     

关于盆地分析思想的发展

中国海陆地区内,沉积岩的分布面积达550万平方公里.这些沉积岩所存在的盆地保留着各种地质作用的记录,赋存着石油天然气和煤炭等矿产资源,是探索地质历史的窗口,也是国民经济建设的重要能源基地.因此,盆地的分析研究显得格外重要,其分析理论思想经历了直观阶段、发展阶段和深化阶段.目前比较完善的是运用综合地球物理方法研究盆地的一套系统工程理论,并将刘光鼎教授提出的综合地球物理解释方法学进一步深化.本文还讨论了盆地分析的有关理论基础.     

Divergent evolution of Earth and Venus: Influence of degassing,tectonics, and magnetic fields

Knowledge of the earliest evolution of Earth and Venus is extremely limited, but it is obvious from their dramatic contrasts today that at some point in their evolution conditions on the two planets diverged. In this paper we develop a geophysical systems box model that simulates the flux of carbon through the mantle, atmosphere, ocean, and seafloor, and the degassing of water from the mantle. Volatile fluxes, including loss to space, are functions of local volatile concentration, degassing efficiency, tectonic plate speed, and magnetic field intensity. Numerical results are presented that demonstrate the equilibration to a steady state carbon cycle, where carbon and water are distributed among mantle, atmosphere, ocean, and crustal reservoirs, similar to present-day Earth. These stable models reach steady state after several hundred million years by maintaining a negative feedback between atmospheric temperature, carbon dioxide weathering, and surface tectonics. At the orbit of Venus, an otherwise similar model evolves to a runaway greenhouse with all volatiles in the atmosphere. The influence of magnetic field intensity on atmospheric escape is demonstrated in Venus models where either a strong magnetic field helps the atmosphere to retain about 60 bars of water vapor after 4.5 Gyr, or the lack of a magnetic field allows for the loss of all atmospheric water to space in about 1 Gyr. The relative influences of plate speed and degassing rate on the weathering rate and greenhouse stability are demonstrated, and a stable to runaway regime diagram is presented. In conclusion, we propose that a stable climate-tectonic-carbon cycle is part of a larger coupled geophysical system where a moderate surface climate provides a stabilizing feedback for maintaining surface tectonics, the thermal cooling of the deep interior, magnetic field generation, and the shielding of the atmosphere over billion year time scales.     

中国气候变迁及其对地理环境的影响

总结了五千年中国历史上的气候变化的特征，论述了气候的冷暖周期性变迁对中国历史地理环境的影响。     

与耀斑相关的磁场演化

本文利用紫金山天文台太阳光谱仪缝前附属Ｄａｙｓｔａｒ滤光器拍摄的，发生在ＮＯＡＡ５３９５活动区中的三个耀斑的Ｈα单色光资料，对比北京天文台怀柔观测站取得的光球磁场资料，研究耀斑产生位置与光球磁场演化的关系，结果表明：（１）在所研究的５０个耀斑亮核中，有３８个位于新浮磁流区附近，另有少数亮核出现在磁对消区；（２）耀斑亮核多集中在横场方向交叉，剪切角大的复杂磁区，耀斑后多数区域磁场结构简化；（３）耀斑