The nature and origin of cratons constrained by their surface geology

作者：A. M. Celâl Şengör, Nalan Lom, Ali Polat · 发表于：Geological Society of America Bulletin · 年份：2021 · DOI：10.1130/b36079.1 · 被引用次数：33 · 研究领域：Geological and Geochemical Analysis、Geochemistry and Geologic Mapping、earthquake and tectonic studies

Abstract Cratons, defined by their resistance to deformation, are guardians of crustal and lithospheric material over billion-year time scales. Archean and Proterozoic rocks can be found in many places on earth, but not all of them represent cratonic areas. Some of these old terrains, inappropriately termed “cratons” by some, have been parts of mobile belts and have experienced widespread deformations in response to mantle-plume-generated thermal weakening, uplift and consequent extension and/or various plate boundary deformations well into the Phanerozoic. It is a common misconception that cratons consist only of metamorphosed crystalline rocks at their surface, as shown by the indiscriminate designation of them by many as “shields.” Our compilation shows that this conviction is not completely true. Some recent models argue that craton formation results from crustal thickening caused by shortening and subsequent removal of the upper crust by erosion. This process would expose a high-grade metamorphic crust at the surface, but greenschist-grade metamorphic rocks and even unmetamorphosed supracrustal sedimentary rocks are widespread on some cratonic surfaces today, showing that craton formation does not require total removal of the upper crust. Instead, the granulitization of the roots of arcs may have been responsible for weighing down the collided and thickened pieces and keeping their top surfaces usually near sea level. In this study, we review the nature and origin of cra...