右江盆地构造和演化及对卡林型金矿床的控制作用

Structural Evolution of the Youjiang Basin and Its Controlling Effects on the Formation of Carlin-type Gold Deposits

右江盆地,又称南盘江盆地,是我国重要的多金属矿床富集地,广泛发育有Au-As-Sb-Hg低温热液矿床,也是我国卡林型金矿大规模富集区之一。矿床地质特征表明,金矿床的形成明显受到构造的控制,因此,探讨盆地的构造演化对于深入研究卡林型金矿的形成具有重要意义。通过结合前人大量研究认为:右江盆地内主要发育有NW和NE向两组构造,NW及NE向的边界断裂对盆地的演化及火成岩的发育起到重要作用;金矿床在平面上均分布于右江盆地范围内,具有明显的岩性和构造控矿的特征;右江盆地形成及后续的构造演化可以分为六个阶段,即:早泥盆世中期滨浅海陆棚发育(D21),中泥盆世—中二叠世裂陷洋盆发育(D2-P2),中二叠世末—中三叠世洋盆消失及前陆盆地发育(P32-T2),晚三叠世—早侏罗世盆地消亡及碰撞后伸展(T3-J1),中侏罗世—早白垩世中期NE向挤压构造发育(J2-K21)和早白垩世晚期—古近纪局部伸展作用(K31-E);右江盆地内卡林型金矿的成矿期集中在前陆盆地发育结束而褶皱成山后,成矿过程与伸展环境密切相关。

The Youjiang Basin, which is also named as the Nanpanjiang Basin, is an important enrichment area of Au-As-Hg-Sbdeposits in South China, and is also one of the largest enrichment area of Carlin-type gold deposits in China. The geologicalcharacteristics of ore deposits indicate that the formation of these deposits has a relationship with the structures. Therefore, detaileddiscussions on the structural characteristics and tectonic evolution of the Youjiang Basin are important for understanding thedevelopment history of gold deposits. Combined with the previous studies, we think that two main sets of structures were developed inthe Youjiang Basin including the NW- and NE-trending ones; The NW- and NE-trending boundary faults played an important role in theevolution of the basin and the distribution of volcanic rocks; All gold deposits are distributed in the basin, and the lithology and structures are the two main factors that control the formation of gold deposits; Evolution of the Youjiang Basin can be divided into sixstages, i.e., the shore-shallow sea shelf development stage in the middle of Early Devonian（D1^2）; the rifted ocean basin developmentstage during the Middle Devonian to the Middle Permian（D2-P2）; the ocean basin disappearance and foreland basin development stageduring the end of Middle Permian to the Middle Triassic（P2^3-T2）; the stage of foreland basin disappearence and post-collision extensionduring the Late Triassic to the Early Jurassic（T3-J1）; the NE-trending compression structure development stage during the MiddleJurassic to the middle of Early Cretaceous（J2-K1^2）; and the partly extension stage during the late Early Cretaceous to the Paleogene.The Carlin-type gold deposits were possibly developed after the foreland basin disappeared, and the ore-forming stage was related to theextensional tectonic environment.