浅析莱芜接触交代-热液铁矿的双交代渗滤作用

莱芜接触交代-热液铁矿赋存于奥陶系马家沟组碳酸盐岩与燕山晚期闪长岩的接触带及其附近.通过对各矿床有益有害组分分析,以及对成矿母岩、围岩岩石化学特征、双交代渗滤作用和围岩蚀变类型等研究,总结出"三位一体"成矿模式,进而探讨了矿体的空间分布规律及其找矿意义.     

胶东西北部玲珑、郭家岭超单元花岗岩成因探讨

玲珑、郭家岭超单元花岗岩的源岩均为胶东岩群变质岩;玲珑超单元花岗岩表现出岩石的不均匀性,其成因为原地、半原地交代-重熔型花岗岩;郭家岭超单元花岗岩则属于有幔源物质参入的同熔型花岗岩.两个花岗岩均经历了多期构造-岩浆作用,最终形成于燕山期;郭家岭超单元最终形成晚于玲珑超单元花岗岩.     

Early Pleistocene climate changes in the central Mediterranean region as inferred from integrated pollen and planktonic foraminiferal stable isotope analyses

Vegetation inherited from a Pliocene subtropical climate evolved through obliquity oscillations and global cooling leading to modern conditions. An integrated, highly time-resolved record of pollen and stable isotopes (δ¹⁸O and δ¹³C of Globigerina bulloides) was obtained to understand vegetation responses to Early Pleistocene climate changes. Continental and marine responses are compared in the Central Mediterranean region with a particular consideration of environmental changes during anoxic events.Pollen data illustrate vegetation dynamics as follows: [1] development of mesothermic elements (warm and humid conditions); [2] expansion of mid- and high-altitude elements (cooler but still humid conditions); and [3] strengthening of steppe and herb elements (cooler and dry conditions). These successions correlate with precession. δ¹⁸O variations recorded by Globigerina bulloides define two cycles (MIS 43-40) related to obliquity. At northern low- to mid-latitudes, the pollen signal records temperature and wetness changes related to precession even during global climate changes induced by obliquity. This may result in unexpected increasing wetness during glacial periods, which has to be considered specific to the Central and Eastern Mediterranean region. Lastly, an analysis of anoxic events reveals that enhanced runoff is indicated by increasing frequency of the riparian trees Liquidambar and Zelkova.     

Paleoenvironmental analysis of a middle Wisconsinan biota site, southwestern Virginia, U.S.A.

The Ratcliff Site in southwestern Virginia lies in a small second-order stream valley filled with approximately 3.5 m of organic-rich deposits that contain bones of mammoth, mastodon, deer (or antelope), logs, and plant macrofossils. Radiocarbon analyses indicate the age of the organic-rich sediment ranges from > 44,000 to 29,100 ¹⁴C yr BP, a time period with no fossil remains reported in this region of the Appalachians. Analyses of field observations, textural data, organic carbon content, and plant macrofossils indicate that the organic-rich sediments contain interbedded standing-water and debris-flow deposits. Up to 6 m of oxidized debris-flow sediments bury the organic-rich sediments. The presence of Rubus parviflorus (Thimble Berry) throughout the deposit indicates the site had a boreal environment from > 44,000 to 29,100 ¹⁴C yr BP. Plant macrofossil evidence indicates the uplands had stands of spruce/jack-pine forests while the valley contained ponds and associated wetlands. Three debris flows occurred at the site between approximately 38,000 and 29,000 ¹⁴C yr BP, suggesting a recurrence interval for major storms of approximately 3000 yr, even though the apparent stability of the boreal environment implies a climate not conducive to catastrophic rainstorms. This conflicting combination of features suggests that during the middle Wisconsinan this area experienced generally cool climates, dominated by polar air masses, but was punctuated by relatively brief warm periods marked by incursions of tropical air masses.     

The future of industrial cities and regions in central and eastern Europe

Economic transition in central and eastern Europe (CEE) has had a particularly strong impact on industrial cities and regions. Following their economic collapse, most of them are now confronted with serious problems such as high unemployment and vast ecological damage. The paper presents findings from a pan European research project that investigated the problems of these cities and regions as well as the strategies being adopted to cope with structural change. It examines the differences in approaches and addresses the question whether existing EU policy is suitable for supporting the redevelopment of old industrial cities and regions in CEE countries. The paper concludes with recommendations for future directions in policy making.     

中亚成矿域斑岩铜（钼）矿带的认识与建立

对中亚成矿域斑岩铜(钼)矿带的认识,起源于哈萨克斯坦滨巴尔喀什—伊犁火山侵入岩带的划分和地球物理场的确认。尤其是对哈萨克斯坦—准噶尔环状磁力异常带的厘定,奠定了中亚成矿域斑岩铜(钼)矿带的地球物理基础和与哈萨克斯坦—准噶尔地块外缘火山-侵入岩带的耦合关系,最终建立起哈—中—蒙中亚成矿域斑岩型铜(钼)矿带的雏型。     

Helium and argon isotopes of the Tertiary basic igneous rocks from Shandong Peninsula and implications for the magma origin

Helium (He) and Argon (Ar) isotopic compositions of the Tertiary basic igneous rocks were determined by the high temperature melting extraction method. The selected samples for the studies included al-kaline basalts and diabases from the Jiyang basin,and the surrounding Shanwang and Qixia outcrops in the Shandong Peninsula,eastern China. The results show that the Paleogene basalts and diabases from the Jiyang basin yielded a wide range of P4 PHe abundance of (73.70-804.16)×10 P-8 Pcm P3 P STP·g P-1 P,with P3 PHe/ P4 PHe ratios of 0.374-2.959 Ra,which was lower than the MORB but evidently higher than the con-tinental crust value. The Neogene alkaline basalts from the Jiyang basin,Shanwang and Qixia outcrops have variable P4 PHe abundances ((42.34-286.72)×10-8 Pcm P3 P STP·g-1 P),and "continental crust-like" P3 PHe/ P4 PHe ratios (0.013-0.074 Ra). All of them contain atmospheric-like P40 PAr/ P36 PAr ratio (395.4-1312.7),reflecting the mantle sources with air components. Their low P3 PHe/ P4 PHe ratios are interpreted as the enrichment of the radiogenic P4 PHe mainly inherited from the mantle. He and Ar systematics show the mixing of MORB-type,air and a P4 PHe enriched member in the mantle source,suggesting that these igneous rocks originated from the depleted asthenospheric mantle mixed with an EMI component. Therefore,the present He and Ar isotopes do not support the viewpoints that the Cenozoic igneous rocks of Eastern North China were the products of mantle plume(s) activities.     

山东胶东半岛地区断裂最新活动性研究

山东胶东半岛地区发育有北北东-北东向和北西西向两组断裂,前者分属蓬莱-栖霞断裂系和即墨-牟平断裂带,为半岛的主体断裂构造;后者分布在半岛北缘及其北侧海域,由多条断裂组成。实地调查表明,断层在第四纪期间是活动的,控制着附近山地和盆地的构造演化与地貌发育,最新活动主要发生在第四纪早期,垂直活动幅度可达百米以上;第四纪晚期,断裂活动性迅速减弱,甚至停止,但依然发现北北东-北东向断裂的多个局部段落还在活动,明显地错断了晚更新世地层,垂直断距最大为10m左右。     

爆裂法作为快速测定流体包裹体中二氧化碳（和其它气体）含量的手段及其在勘探中的使用：以中国山东和河北省金矿为例

The acoustic decrepitation method heats a small monomineralic sample and counts pressure impulses as the inclusions burst when they develop high internal pressures.For aqueous fluids,the decrepitation temperature is correlated with the homogenisation temperature,but gas rich fluids give a distinct and characteristic low temperature decrepitation peak which can be used to recognize gas rich fluid inclusions.This information is useful in exploration for Au deposits,which are frequently associated with CO_2 rich and sometimes CH_4 rich fluids. This distinctive decrepitation occurs because the CO_2 rich inclusion fluids expand according to the gas law and develop internal pressures high enough to burst the host mineral grain at temperatures well below their homogenisation temperatures.In contrast,aqueous fluids condense to a liquid and vapour phase during post-entrapment cooling.Upon subsequent heating their internal pressures do not increase significantly until after homogenisation to a single phase occurs and hence they do not decrepitate"prematurely"as gas rich inclusions do. This behaviour is usually regarded as an annoyance in conventional microthermometric homogenisation studies,but can readily be used as an exploration aid to find mineralisation deposited from such gas rich fluids.Decrepitation results on samples from Cowra Ck, NSW,Australia,which have also been microthermometrically measured for CO_2 content,show that amounts of less than 5 mole % CO_2 are easily distinguished by decrepitation and amounts as low as 1 mole % CO_2 may be determinable. Examples of the use of acoustic decrepitation in the study of 6 gold mines in the Shandong and Hebei provinces of China are discussed.     

The Alleret maar (Massif Central, France): A new lacustrine sequence of the early Middle Pleistocene in western Europe

The Alleret maar (Massif Central, France) provides a long lacustrine sequence (40.6 m) attributed to the early Middle Pleistocene. Sediment, pollen and diatoms analysis of its upper part (AL2 core, 14.6 m) indicates two temperate phases marked by high lake levels, forest development and vegetation expansion. They are separated by a cold period during which lake level drops, coarse sediment input increases and steppic and xerophilous plants develop. Pollen data suggests that this sequence belongs to the upper part of the Cromerian complex. These results are in agreement with the 557 ± 3 ka (±12 ka, including all errors) ⁴⁰Ar/³⁹Ar age obtained from an interbedded tephra layer emitted by the Mont-Dore/Sancy strato-volcano and establish that this sequence probably covers the MIS 15 substages.