STRUCTURE OF THE HIGH-GRADE OPATICA BELT AND ADJACENT LOW-GRADE ABITIBI SUBPROVINCE, CANADA - AN ARCHEAN MOUNTAIN FRONT

被引：82

作者：

SAWYER, EW ^{[1
]}

BENN, K ^{[1
]}

机构：

[1] UNIV OTTAWA,OTTAWA CARLETON GEOSCI CTR,DEPT EARTH SCI,OTTAWA K1N 6N5,ON,CANADA

来源：

JOURNAL OF STRUCTURAL GEOLOGY | 1993年 / 15卷 / 12期

基金：

加拿大自然科学与工程研究理事会;

关键词：

D O I：

10.1016/0191-8141(93)90005-U

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

Plutonic gneisses in the Archaean Opatica Belt in Canada record crustal-scale, WSW-vergent (i.e. longitudinal), high-temperature D-1 ductile shearing. Similar structures occur in adjacent greenstone belts, but only in narrow amphibolite facies zones near the base; metavolcanics in the greenschist facies portions do not record penetrative D-1 structures. The greenstone belts are interpreted as allochthonous on the gneisses; they form the uppermost D-1 thrust sheets. SSE-vergent (i.e. approximately transverse) D-2 thrusting imbricated the Opatica Belt and formed a large antiform-either a culmination or an antiformal stack-in the southern Opatica. The imbricated Opatica Belt wedged under the northern part of the Abitibi Subprovince and created a tight syncline with NNW-vergent D-2 thrusts (interpreted as backthrusts) on its northern limb. The Opatica Belt-Abitibi Subprovince contact, therefore, resembles some Phanerozic mountain fronts. Further southwards-propagating imbrication of the crust beneath the Abitibi Subprovince created a S-vergent foreland fold and thrust belt in the overlying greenstones. High-grade Opatica gneisses and adjacent low-grade Abitibi greenstones contain complementary structural patterns and may therefore represent the internal and foreland parts of an Archaean mountain belt, similar in many respects to Phanerozoic examples.

引用

页码：1443 / 1458

页数：16

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