Geological Evolution of the Longmenshan lntracontinental Composite Orogen and the Eastern Margin of the Tibetan Plateau

• Published in: 地球科学学刊：英文版 2013 (6), p.874-890
• Main Author: 刘树根 邓宾 李智武 Luba Jansa 刘顺 王国芝 孙玮
• Format: Article
• Language: English
• Subjects: 冷却过程; 地质演化; 晚三叠世; 构造复合; 锆石年龄; 陆内造山带; 青藏高原东缘; 龙门山
• ISSN: 1674-487X; 1867-111X

ABSTRACT： The Longmenshan Range is a tectonically composite intracontinental orogen. Its structure, deformation and spatial evolution reflect multiple kinematic eposides and variable dynamics especially during Post-Middle to Post-Late Triassic time. Field work, lower-temperature thermochronological data and U-Pb detrital zircon ages indicate document down-dip zonation and along-strike segmentation dem- onstrated by significant differences in geological structure, intensity of deformation and deformation- involved strata, uplift and cooling processes. Low-temperature thermochronology and U-Pb detrital zir- con ages reveal a period of tectono-thermal quiescence with slow uplift and cooling during post Early Norian to Rhaetian orogeny, followed by rapid cooling and uplift during the Late Cenozoic accompanied by coeval southeastward thrusting and southwestward propagation of defromation. The Longmenshan Range formed by S-N striking compression exerted by the Qinling orogen, E-W striking compression by the Tibetan Plateau and SE-striking compression by the Yangtze Plate. We propose a southwestward propagation model for the Longmenshan Range based our observations of zonation, segmentation and composite evolutional processes during the Late Triassic superimposed by development of the differen- tial uplift and cooling processes that shows southern segments of the Longmenshan Range during Post-Jurassic times.