Terrane and basement discrimination in northern Britain using sulphur isotopes and mineralogy of ore deposits
Terrane and basement discrimination in northern Britain using sulphur isotopes and mineralogy of ore deposits
复制标题
使用硫同位素和矿床矿物学对英国北部的地体和基底进行区分
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
N. Grassineau
中科院分区：
文献类型：
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作者：
D. Lowry;A. Boyce;A. E. Fallick;W. E. Stephens;N. Grassineau
摘要本文对英国北方四个特征明显的相邻火山岩进行了研究，概述了硫同位素的变化，评估了地壳和地幔硫的总体重要性，并提出了一个可用于区分整个北大西洋加里东地区火山岩的模型。矿化中金属成分的特征提供了额外的信息，这些信息可以与下面的基底的性质和事件有关，从沉积开始到地层相连的岩石包中矿化停止。δ 34 S数据表明，各地幔中的主要地壳单元，无论是上地壳沉积物还是地幔基底，都是地幔硫的主要替代源，也是壳下熔体的主要污染源。与花岗岩有关的矿化的δ 34 S值要么在-3 ‰ ~+3‰的壳下熔融范围内，要么偏离于花岗岩中主要地壳单元的值，即南部高地的δ 34 S值趋于亏损，而莱克斯曼和格兰扁花岗岩的δ 34 S值趋于富集。北方高地的更复杂的矿化作用与上地壳变质沉积物下厚的北大西洋克拉通的存在有关。在整个区域内，不受岩浆成分影响的矿脉系统代表了来自当地上地壳单元的均质硫、金属和流体。硫同位素数据和矿化风格的英属锡矿石相比，在加拿大东部沿走向相似的年龄锡矿石揭示显着的相关性。
Abstract This study of four well characterized and adjacent terranes in Northern Britain outlines the sulphur isotope variations, assesses the overall importance of crustal and mantle sulphur, and presents a model that can be applied to terrane distinction throughout the North Atlantic Caledonides. The characteristics of metal components within the mineralization provide additional information that can be related to the nature of underlying basement and events from the onset of sedimentation to the cessation of mineralization within stratigraphically linked packages of rock. The δ34S data show that the dominant crustal units in each terrane, whether upper crustal sediments or cratonic basement, provide the main alternative sulphur source to the mantle and act also as the main contaminant of subcrustal melts. The δ34S values of granitoid-related mineralization are either within the subcrustal melt-range of −3‰ to +3‰ or deviate toward the values of major crustal units in the terrane, i.e. toward 34S depletion in the Southern Uplands and toward 34S enrichment in the Lakesman and Grampian terranes. More complex mineralization in the Northern Highland terrane is linked to the presence of thick North Atlantic craton beneath upper crustal metasediments. Across the region the vein systems beyond the influence of magmatic components represent homogenized sulphur, metals and fluids from local upper crustal units. The sulphur isotope data and style of mineralization for the British terranes are compared with terranes of similar age along strike in Eastern Canada revealing notable correlations.