Isotope hydrological study of mean transit time in the granitic Strengbach catchment (Vosges massif,France): application of the FlowPC model with modified input function

Measurements of ¹⁸O concentrations in precipitation, soil solution, spring and runoff are used to determine water transit time in the small granitic Strengbach catchment (0·8 km²; 883–1146 m above sea level) located in the Vosges Mountains of northeastern France. Water transit times were calculated by applying the exponential, exponential piston and dispersion models of the FlowPC program to isotopic input (rainfall) and output (spring and stream water) data sets during the period 1989–95. The input function of the model was modified compared with the former version of the model and estimated by a deterministic approach based on a simplified hydrological balance. The fit between observed and calculated output data showed marked improvements compared with results obtained using the initial version of the model. An exponential piston version of the model applied to spring water indicates a 38·5 month mean transit time, which suggests that the volume in the aquifer, expressed in water depth, is 2·4 m. A considerable thickness (>45 m) of fractured bedrock may be involved for such a volume of water to be stored in the aquifer. Copyright © 2005 John Wiley & Sons, Ltd.     

崂山花岗岩地区含锶、偏硅酸矿泉水的形成机理

报道了崂山花岗岩地区矿泉水的特征。指出其矿泉类型为含锶、偏硅酸型，并讨论了其形成机理。     

Estimating Influence of Crystallizing Latent Heat on Cooling-Crystallizing Process of a Granitic Melt and Its Geological Implications

Based on the theory of thermal conductivity, in this paper we derived a formula to estimate the prolongation period （AtL） of cooling-crystallization process of a granitic melt caused by latent heat of crystallization as follows：△tL=QL×△tcol/（TM-TC）×CP where TM is initial temperature of the granite melt, Tc crystallization temperature of the granite melt, Cp specific heat, △tcol cooling period of a granite melt from its initial temperature （TM） to its crystallization temperature （Tc）, QL latent heat of the granite melt.
The cooling period of the melt for the Fanshan granodiorite from its initial temperature （900℃） to crystallization temperature （600℃） could be estimated -210,000 years if latent heat was not considered. Calculation for the Fanshan melt using the above formula yields a AtL value of -190,000 years, which implies that the actual cooling period within the temperature range of 900°-600℃ should be 400,000 years. This demonstrates that the latent heat produced from crystallization of the granitic melt is a key factor influencing the cooling-crystallization process of a granitic melt, prolongating the period of crystallization and resulting in the large emplacement-crystallization time difference （ECTD） in granite batholith.     

四川德格错阿金矿特征与矿床成因初析

错阿金矿床赋存于理塘义敦群上三叠统瓦能组变基性火山岩中,金矿体受次级北北西-近南北向韧性-脆韧性剪切变质带控制,与金矿化有关蚀变主要为黄铁矿化、辉锑矿化和硅化、碳酸盐化、金云母化及石墨化。矿床成因为蚀变构造型。甘孜-理塘断裂带北段嗄拉、错阿、海子口三个矿化集中区内大部份化探异常具有面积大、强度高、梯度变化大、元素组合好等特点,具有很好的找矿前景。     

CCSD主孔1113~1600 m花岗质片麻岩单元的变形构造特征

中国大陆科学钻探(CCSD)主孔2000m岩性剖面揭示了1113～1600m花岗质片麻岩段为地表北苏鲁超高压花岗质变质岩剪切构造叠覆岩片中的石湖镇构造岩片的花岗质片麻岩的下延部分。本单元之上下界线为韧性剪切带,内部发育小型韧性剪切变形,仅局部可见旋转碎斑体系等剪切指向标志,以SE向NW的逆冲剪切指向为主,其次为NW向SE的正滑剪切指向,并主要发育于较软弱夹层内,后者成为苏鲁地区存在伸展型穹隆构造的新证据;在1140～1280m岩性段内发育断续、较弱的拉伸线理,拉伸线理总体向SE倾伏,倾伏角为10～36°;花岗质片麻岩单元内部分石英以多晶石英条带的形式存在,花岗质片麻岩主要矿物长石基本没有动态重结晶现象,仅具较弱的形态拉长特征(X∶Z=2左右),总体面理倾向170°E,倾角平均20°,明显不同于其他岩性单元内的面理产状,可能主要代表折返变形之前的近东西向构造,而其他岩性单元受折返变形影响较大,其面理产状主要代表折返阶段形成的NE-NNE向构造;运用电子背散射(EBSD)技术进行石英组构分析并与费氏台测定对比,表明1113～1600m花岗质片麻岩单元经历了中—低温变形,局部残留有高温组构,剪切指向主要为SE向NW的逆冲,其中高温组构与中温组构均显示为SE向NW的逆冲剪切指向,反映折返早期与折返主期岩片的相对剪切方向一     

河南焦作云台山早前寒武纪变质基底锆石SHRIMP U-Pb年龄

应用离子探针技术,对华北太行山南缘钾长石化长英质副片麻岩和钾长石化片麻状奥长花岗岩进行了锆石年龄测定。钾长石化长英质副片麻岩的变质原岩为泥砂质碎屑沉积岩,其形成时代很可能为新太古代。碎屑锆石普遍存在强烈铅丢失,靠近上交点的5个数据点207Pb/206Pb加权平均年龄为3399Ma±8Ma,代表了物源区组成的时代。钾长石化片麻状奥长花岗岩2组锆石207Pb/206Pb加权平均年龄分别为2511Ma±13Ma(岩体形成时代)和2735Ma±16Ma(残余锆石年龄),分别代表该岩体形成时代和残余锆石年龄。新的资料支持了华北克拉通中部造山带太古宙地质体与其东部陆块存在亲缘关系的认识。     

福建南平花岗伟晶岩中钾长石的矿物学研究

钾长石是南平伟晶岩中分布广泛的一种造岩矿物，它的结晶作用几乎贯穿于伟晶岩形成－演化过程的所有阶段。通过对不同类型伟晶岩和同一类型伟晶岩中不同世代钾长石的产出条件、物理性质、矿物粉晶X光衍射、化学成分等方面研究，发现钾长石在伟晶岩中的分布有明显的规律性。这不仅深化了对南平伟晶岩形成机制的了解，而且对钾长石的综合利用也有重要意义。     

Petrogenesis of the Ulsan carbonate rocks from the south-eastern Kyongsang Basin, South Korea

Abstract The petrogenesis of the Ulsan carbonate rocks in the Mesozoic Kyongsang Basin of South Korea, which have previously been interpreted as limestone of Paleozoic age, is reconsidered in the present study. Within the Kyongsang Basin, a small volume of carbonate rocks, containing a magnetite deposit and spatially associated ultramafic rocks, is surrounded by sedimentary, volcanic and granitic rocks of the Mesozoic age. The simple cross‐cutting relationships and other outcrop features of the area indicate that the carbonate rocks are an intrusive phase and younger than the other surrounding Mesozoic rocks. The Ulsan carbonates have low concentrations of rare earth elements (REE) and trace elements with the carbon and oxygen isotope values in the range of δ¹³C_PDB = 2.4 to 4.0‰ and δ¹⁸O_SMOW = 17.0 to 19.5‰. Outcrop evidence and geochemical signatures indicate that the Ulsan carbonates were formed from crustal carbonate melts, which were generated by the melting/fluxing of crustal carbonate materials, caused by the emplacement‐related processes of alkaline A‐type granitic rocks. Compared to typical mantle‐derived carbonatites associated with silica‐undersaturated, strongly peralkaline systems, the relatively small size and geochemical characteristics of the Ulsan carbonates reflect carbonatite genesis in a silica‐saturated, weakly alkali intrusive system. Major deep‐seated tectonic fractures formed by the collapse of the cauldron or the rift system associated with the opening of the East Sea (Japan Sea) might have facilitated the ascent of the crustal carbonate melts.     

胶东招掖郭家岭型花岗岩锆石年代学及其Pb同位素特征

采用SHRIMP测年技术，精确地测定了郭家岭型花岗岩年龄为130-126Ma，主要金矿化在126-120Ma之间，郭家岭型花岗岩与金矿化关系最密切。岩体Pb同位素组成反映了本区所处构造背景。