Sudbury Breccia distribution and orientation in an embayment environment
Sudbury Breccia distribution and orientation in an embayment environment
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海湾环境中萨德伯里角砾岩的分布和方向
DOI：
10.1130/0-8137-2339-6.305
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发表时间：
1999
影响因子：
4.9
通讯作者：
W. Peredery
中科院分区：
文献类型：
--
作者：
J. Fedorowich;D. H. Rousell;W. Peredery
萨德伯里角砾岩的分布模式和角砾化强度一般不能很好地限制在萨德伯里火成岩周围5-15公里宽的区域内。这一地区被盛产萨德伯里角砾岩的当地地区所点缀。本章的目的是量化一个这样的地区--斯特拉斯科纳海湾内的分布和方向。对萨德伯里角砾岩百分比分布的估计是基于详细的野外测绘。例如，在一个7平方公里的地区，只有4.7%的露头面积(22.8%)由萨德伯里角砾岩组成。该地区被细分为不同的分区，萨德伯里角砾岩含量从2%到8%不等，其中最集中在斯特拉斯科纳湾附近。海湾被解释为萨德伯里火成岩杂岩下盘的塌陷特征，反映了因陨石撞击角砾岩而在结构上被削弱的地面的改造。这些测量的结论之一是，萨德伯里角砾岩的分布可以用来预测整个萨德伯里盆地中赋存镍-铜-铂族元素(Ni-Cu-PGE)矿床的海湾构造。Strathcona矿的萨德伯里角砾岩的一个大型网络由中心的46%的角砾岩组成，而相邻的上盘和下盘只有4%-18%的角砾岩。萨德伯里角砾岩的类迪克力体和脉具有广泛的不同方向，与萨德伯里火成岩杂岩的外缘近平行地聚集在一起，并且与该杂岩一样，倾角随深度减少。萨德伯里角砾岩的包体受反向剪切力和正向剪切力的控制，在整体挤压状态下与张性开口相互作用，最大挤压与萨德伯里火成岩杂岩的外部接触近似垂直。
The distribution patterns and brecciation intensity of Sudbury Breccia are generally not well constrained within a 5–15-km-wide zone that surrounds the Sudbury Igneous Complex. This zone is punctuated by local areas of abundant Sudbury Breccia. The object of this chapter is to quantify the distribution and orientation within one such area, the Strathcona Embayment. Estimates of the percentage distribution of Sudbury Breccia are based on detailed field mapping. For example, in a 7-km2 area, only 4.7% of the total outcrop area (22.8%) consists of Sudbury Breccia. The area was subdivided into subareas varying from 2 to 8% Sudbury Breccia content, with the highest concentration in the immediate vicinity of the Strathcona Embayment. Embayments are interpreted as slump features in the footwall to the Sudbury Igneous Complex and reflect a reworking of ground that has been structurally weakened by meteorite impact brecciation. One of the conclusions from these measurements is that Sudbury Breccia distribution can be used to predict embayment structures, which host nickel–copper–platinum group element (Ni-Cu-PGE) deposits throughout the Sudbury Basin. A large network of Sudbury Breccia in the Strathcona mine consists of 46% breccia in the center, and only 4–18% in the adjoining hangingwall and footwall. Dikelike bodies and veins of Sudbury Breccia have widely variable orientations that cluster subparallel to the outer margin of the Sudbury Igneous Complex and, like the complex, decrease in dip with depth. Envelopes of Sudbury Breccia are controlled by reverse and normal shears that are interactive with tensional openings in an overall compressional regime with maximum compression approximately orthogonal to the outer contact of the Sudbury Igneous Complex.