Contents of Volume 25

Volume Contents

Contents of Volume 25     

The Andalusian earthquake of 25 December 1884

Data concerning this earthquake and the seismicity of the surrounding area have been examined. Large historical earthquakes before 1884 show that destructive shocks in the area have a recurrence period of about two hundred years. Recent seismic activity has been high from 1910 to 1955 and lower thereafter. Total number of casualties for the 1884 earthquake is estimated at 745 dead and 1475 wounded. Damage to buildings extended to 4399 houses totally destroyed and 6316 partially damaged. A new intensity map has been drawn from the original reports fron which the approximate location of the epicenter, depth of focus, attenuation of energy and source dimensions have been determined. The aftershock sequence of felt events lasted for nearly a year with an increase of activity at the second month.     

Two contrasting granite types: 25 years later

The concept of I‐ and S‐type granites was introduced in 1974 to account for the observation that, apart from the most felsic rocks, the granites in the Lachlan Fold Belt have properties that generally fall into two distinct groups. This has been interpreted to result from derivation by partial melting of two kinds of source rocks, namely sedimentary and older igneous rocks. The original publication on these two granite types is reprinted and reviewed in the light of 25 years of continuing study into these granites.     

《现代地质》2011年(第25卷)总目次

<正>~~     

25 years of mineral exploration and discovery in Indonesia

This paper traces the history of mineral exploration in Indonesia between 1967 and 1992, and discusses various technical aspects, such as area selection, exploration and discovery methods, and significant geologic features of the more important new discoveries.Exploration activity over the past 25 years can be divided into four main phases. Phase 1 (1967–1976) mostly involved investigations of mineral prospects and districts previously identified by the Dutch. These investigations resulted in many discoveries, including: a major copper-gold district (skarn-porphyry copper) in Irian Jaya, where exploration is still in progress (resources identified to date: 28 Mt Cu and 2,700 t Au); large nickel resources in Eastern Indonesia (13 Mt Ni); significant onshore and offshore tin resources in the Sumateran tin belt (0.13 Mt Sn); and large but low grade bauxite deposits in West Kalimantan (300 Mt Al₂O₃). Of the eight Contracts of Work signed between 1967 and 1972, six reached the mining stage. Phase 2 (1970–1975) consisted of an extensive porphyry copper search in the Sunda arc, the western arc of Sulawesi and the central belt of Irian Jaya. Best results were obtained from northern Sulawesi, where follow-up between 1976 and 1982 identified three potentially economic copper-gold deposits (1.7 Mt Cu and 140 t Au) and one subeconomic molybdenum porphyry system (0.8 Mt Mo). During Phase 3 (1981–1988) extensive coal exploration in South and East Kalimantan delineated over 5,000 Mt of coal of varying rank and quality, including 1,500 Mt as measured reserves in 17 deposits, eight of which have been developed to date. Phase 4 (1984–1990) involved a major gold rush, focused primarily on the Cenozoic magmatic belts of Kalimantan, Sulawesi, Moluccas and the Sunda arc. Over 80 primary and alluvial gold prospects were drill tested. Five of these were brought into production (two alluvial deposits, two new hard rock discoveries and one Dutch mine), containing approximately 135 tonnes of mineable gold, and several other projects are under development or undergoing feasibility studies. Total geological resources identified to date are estimated to contain about 700 tonnes of gold. Exploration during phase 4 also resulted in several gold-rich porphyry copper discoveries, including a major deposit in Sumbawa (2.7 Mt Cu and 250 t Au). Intermittent exploration for uranium, diamonds and lead/zinc since 1969 has been largely unsuccessful.Exploration is now passing to the next phase, which is likely to be multi-commodity in nature with a strong focus on gold, copper and coal. A number of deposits outlined during earlier phases will be developed.The unprecedented high level of mineral exploration activity over the past 25 years can be attributed to Indonesia's mineral prospectivity and favourable investment climate. Given a continued competitive commercial environment and sustained commodity prices, the next 25 years should see further strong development of the country's mineral resources.     

《沉积学报》2007年第25卷总目录

第1期·层序地层学·饶阳凹陷下第三系层序类型及发育模式…………………………………………纪友亮杜金虎赵贤正张以明张瑞峰(1)藏南洛扎地区侏罗纪—早白垩世层序地层与地层格架———兼论基本层序变化规律调查在区调工作中的运用夏军钟华明童劲松鲁如魁(10)…………………………………………………………………………………………………………………干旱气候条件下陆相高分辨层序地层特征研究———以江汉盆地西南缘晚白垩世渔洋组为例陈波张昌民韩定坤赵海涛赖志云(21)………………………………………………………………………………………     

25-降藿烷系列化合物及其在油藏地球化学研究中的应用

通过阐述烃源岩及原油中25-降藿烷系列化合物的结构、鉴定方法、成因（生物降解作用、原生作用）、降解机理,系统介绍了目前国内外25-降藿烷系列化合物的研究现状。认为25-降藿烷系列化合物在油源对比和油气成藏方面的应用和研究,有助于推动油藏地球化学的发展,同时也存在一些局限性。