Sunrise Hill unconformity: A newly discovered regional hiatus between Archaean granites and greenstones in the northeastern Pilbara Craton

Contacts between Archaean granites and greenstones in the northeastern part of the Pilbara Craton have been described as intrusive and tectonic. New field observations in the Shay Gap region demonstrate that greenstones of the Gorge Creek Group unconformably overlie the Muccan and Warrawagine batholiths. Regionally, the unconformity is marked by a persistent but relatively thin basal clastic sequence, locally with a granite boulder conglomerate, overlain by ore‐bearing banded iron‐formation, fine‐grained clastic rocks and chert. The granite basement is dated at 3443 ± 6 Ma. The precise age of the hiatus is unknown but its maximum effect might have been the removal of a substantial thickness of Early to Middle Archaean strata.     

Steroid and triterpenoid distributions in bransfield strait sediments: Hydrothermally-enhanced diagenetic transformations

Recent sediments from Bransfield Strait, Antarctica have been analyzed for triterpenoid and steroid hydrocarbons, sterols and steroid ketones to consider the effects of hydrothermal fluids on the sedimentary organic matter. The steroid distributions in unaltered and altered sediments are controlled more by inputs from source organisms than by the effects of hydrothermal activity, which is suggested to be limited to low temperature alteration. Nevertheless, chemical reactions occurred in altered sediments and include dehydration of sterols to sterenes, isomerization of triterpenes and sterenes, rearrangement of sterenes to diasterenes and reductive processes leading to generation of phytane from phytol via phytenes.     

西藏羊八井地热田水热蚀变

本文对羊八井地热田钻扎ZK-201、ZK-301和ZK-308的岩心进行了较系统的蚀变矿物学、岩石学和流体包体研究。划分出6个蚀变矿物共生组合及蚀变分带,讨论了蚀变过程中岩石化学变化的特点,并推测了蚀变的温度和酸碱度条件。研究表明,热田曾处于极度的活动状态,最高温度达220-240℃,由于冷水的入侵,热田在目前钻探所及范围已冷却了50-70℃。蚀变矿物分布模式表明,目前热田流体主通道位于北部,热田进一步的开发应以寻找北部深部高温流体为主。     

Iron porphyrins in the Permian Kupferschiefer of the lower Rhine Basin, N.W. Germany

Immature samples of the Permian Kupferschiefer from the Lower Rhine Basin in N.W. Germany were analysed for tetrapyrrole pigment type and abundance. The sediment, thought to have been deposited in a marine regime with enhanced salinity, was found to contain high concentrations of metalloporphyrins. The porphyrins are complexed to nickel (Ni) and oxovanadium (V=0), but high abundances of iron (Fe) porphyrins were also detected using UV/visible spectroscopy and mass spectrometry. The presence in the latter of series of aetioporphyrins, cycloalkanoporphyrins, di-cycloalkanoporphyrins and benz-cycloalkanoporphyrins was confirmed by accurate mass measurements; HPLC co-injection of deoxophylloerythroetioporphyrin (C₃₂ DPEP) with the demetallated iron porphyrins indicated its presence in the sediment as an iron complex. The study provides the first evidence for the occurrence of Fe porphyrins in geological samples other than coals and lignites, and reports the highest concentrations in sedimentary organic matter to date.     

游离氧化铁形态转化对红粘土工程性质的影响

本文通过模拟环境中的有机质使游离氧化铁形态转化对典型红粘土工程性质的影响试验,系统地测试了游离氧化铁的形态分布与物性指标的关系。试验结果表明,在渍水条件下,游离氧化铁的形态转化对红粘土性质的影响不显著,但在渗水条件下,由于游离氧化铁的流失使得胶结作用减弱,它对红粘土工程性质的影响逐渐明显,其潜在的危害仍然是不容忽视的。     

金沙江—澜沧江—怒江地区金矿类型及成矿条件

金沙江-澜沧江-怒江地区是中国重要的贵金属、有色金属成矿远景区之一。金矿类型繁多,主要有:蛇绿混杂岩中的构造蚀变岩型;与中酸性岩浆侵入活动有关的多金属石英脉型;构造破碎带中的微细浸染型;碳酸盐岩层构造裂隙中的混成热液型;与次火山岩有关的热液型;火山热泉型和海底火山喷流沉积-热液改造型。成矿时间集中于中新生代。矿床和矿体主要受线型构造控制。岩浆活动在金的成矿过程中有不同程度影响。金矿基本属浅成、中低温热液型。蚀变作用普遍强烈。成矿物质及热液具多源性。     

块状硫化物矿床的地球化学找矿标志

近年来国外发现了许多大型块状硫化物矿床，而我国进展还不大。原因之一是我们对这类矿床的地质特征，成矿条件尤其是找矿标志研究还不够。这是一类成矿物质通过热液作用在海底沉积而成的特殊矿床，故在找矿勘探讨既要研究沉积矿时形成的原生晕，又要研究热液经过围岩时蚀变而产生的次生晕?Ｍｎ晕，Ｔｌ，Ｈｇ，Ｂａ，Ａｓ和Ｚｎ等元素的异常，络合剂元素的富集，微量元素的分布，铅同位素，岩石化学异指数尤其是块状硫化物Ｃｕ矿中     

微波等离子体炬原子发射光谱法测定铁和铝的研究

研究了低功率微波等离子体炬原子发射光谱法（ＭＰＴ－ＡＥＳ）对Ｆｅ，Ａｌ的测定。样品经气动雾化后，分别以流动注射与连续式两种方式引入ＭＰＴ。考察了用这两种进样方式时ＭＰＴ－ＡＥＳ的分析性能，证明低功率ＭＰＴ－ＡＥＳ具有良好的分析特性。     

四川紫色水稻土氧化铁的分异

以岷江冲积物、黄壤残积物发育成的水稻土为对照,研究了紫色砂岩泥岩母质发育成的紫色水稻土氧化铁的形态及其含量和转化。揭示了紫色水稻土具有无定形铁含量,铁活化度较高,氧化铁的转化作用较弱等独特的发生特性。     

冀东迁安铁矿区早前寒武纪硅铁岩矿层褶皱变形序列

文中根据硅铁矿层的褶皱形态、复合关系等确定迁安铁矿区在中元古代之前发生过6期褶皱变形,叙述了这6期褶皱的特征和分布,讨论了褶皱的成因。区内各期褶皱形态演化规律反映了变形过程中岩石塑性有规律递减的特点。这一演化规律对研究早前寒武纪地区褶皱变形和指导该区找矿工作有重要意义。