Hot Paper - Syn-Faulting Calcite Ages: Constraint for the Late Mesozoic Deformation of the Ningzhen Mountain, Eastern China

Syn-Faulting Calcite Ages: Constraint for the Late Mesozoic Deformation of the Ningzhen Mountain, Eastern China

同步断裂方解石时代：中国东部宁镇山晚中生代变形的约束
Syn-Faulting方解石年代：中国東部、Ningzhen山の中生代後期の変形に対する制約
Syn-Faulting 방해석 시대: 중국 동부 Ningzhen Mountain의 중생대 후기 변형에 대한 제약
Edades de calcita con fallas sintéticas: restricción para la deformación mesozoica tardía de la montaña Ningzhen, este de China
Âges de calcite syn-faulting : contrainte pour la déformation mésozoïque tardive de la montagne Ningzhen, est de la Chine
Син-разломные кальцитовые эпохи: ограничение позднемезозойской деформации горы Нинчжэнь, Восточный Китай

Jinbao Su 苏金宝 ¹, Hongbing Tan 谭红兵 ², Yuexing Feng 俸月星 ³, Guoxing Qin ²

¹ College of Oceanography, Hohai University, Nanjing 210098, China
中国南京河海大学海洋学院
² School of Earth Sciences and Engineering, Hohai University, Nanjing 210098, China
中国南京河海大学地球科学与工程学院
³ School of Earth Sciences, The University of Queensland, Brisbane QLD 4072, Australia

https://doi.org/10.1007/s12583-020-1107-2

http://en.earth-science.net/en/article/doi/10.1007/s12583-020-1107-2

Journal of Earth Science, 30 December 2021

Abstract

It is difficult to date a brittle fault because of the absence of effective dating methods. Recently, calcite U-Pb dating has drawn the attention of many researchers and has been successfully applied to constrain the age of brittle deformation.

The South China Block (SCB) has experienced multiphase deformations characterized by widespread brittle faults and folds, which has led to significant debate on the Mesozoic dynamic mechanism and deformational phases. A syn-faulting calcite vein that occurred in the Permian limestones of the Ningzhen Mountain region was analyzed using U-Pb dating and geochemistry techniques in this paper. The U-Pb dating results display multiphase activities with two mixed ages of 109.9±5.8 Ma (MSWD=46, n=231) and 117.2±2.4 Ma (MSWD=3.6, n=150). The age of 117.2±2.4 Ma likely represents the timing of the brittle faults.

Trace elements and rare earth elements data indicate that these fault-related calcites are mainly derived from host limestones and unrelated to Cretaceous magmatic activity. These faults formed in a tectonic reactive period and dormant time of the adakitic magma in the Lower Yangtze region.

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