Paleoproterozoic Granulites in the North China Craton and Their Geological Implications

Abstract

AbstractIt is well known that there are widespread Paleoproterozoic high-grade rocks, mainly garnet amphibolites and granulites, in the North China Craton. The granulites could be classified into two types, the high-pressure granulites and (ultra-)high-temperature granulites. The high-pressure granulites mainly distribute in the Huai’an-Xuanhua, Hengshan, Fuping, Zanhuang, Qianlishan–Helanshan, and Jiaobei regions (the central and east of the craton), while the (ultra-)high-temperature granulites distribute mainly in the Liangcheng–Jining–Zhuozi and the Daqingshan regions (west of the northern margin of the craton). Nevertheless, (ultra-)high-temperature granulites have been also discovered in northeast Hebei, north Henan, Shandong and Liaoning provinces, and the Korean peninsula, and some drilling cores from under the Ordos basin, though some of them might be formed in the Late Archean. The Paleoproterozoic high-grade metamorphism has partly overprinted on the Late Archean low- to high-grade rocks. Both types of granulites have recorded clockwise P-T paths, which might indicate a process similar to those happened in the Phanerozoic orogenic belts. In the past 20–30 years, several different tectonic models have been introduced to interpret the environments of the Paleoproterozoic granulites in the North China Craton. However, there are several things need to be clarified before any conclusion, e.g., (1) the distribution of the different types of high-grade rocks; (2) the relationship between the high-pressure granulites and the (ultra-)high-temperature granulites; and (3) the exhumation rate and genetic mechanism of these rocks. These Paleoproterozoic high-grade rocks in the North China Craton are more complex than any high-grade rocks in the Phanerozoic orogens, and await further study.KeywordsNorth China CratonPaleoproterozoicHigh-pressure granuliteUltra-high-temperature granulite