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Basement Characteristics and Crustal Evolution of the Copper‐Gold Metallogenic Belt in the Middle and Lower Reaches of the Yangtze River: Some Isotope Constraints
Author(s) -
Taofa ZHOU,
Shucang YUE
Publication year - 2000
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2000.tb00451.x
Subject(s) - proterozoic , geology , crust , mantle (geology) , archean , geochemistry , basement , precambrian , metamorphic rock , mesozoic , petrology , paleontology , tectonics , civil engineering , structural basin , engineering
Studies of the Pb, Sr and Nd isotopic composition of Mesozoic intrusive rocks indicate that the basement of the copper‐gold metallogenic belt of the middle and lower reaches of the Yangtze River has “two‐layer structure” and partly has “multi‐layered structure”, and is inhomogeneous and shows the distinct feature of E‐W provincialism. The calculated model lead ages ( t 1 ) are mostly greater than 2600 Ma, and the model neodymium ages ( T DM ) vary from 953 to 2276 Ma and concentrate in two time intervals: 1800–2000 Ma and 1200–1600 Ma. It is concluded that the basement of the MBYR is composed of the Late Archaeozoic to Middle Proterozoic metamorphic series and that the crust was initiated in the Archaean and continued to grow in the Early and Middle Proterozoic, and the proportion of new crust formed by mantle differentiation during the Late Proterozoic is low.