| 摘要: |
| 新生代印度-欧亚板块碰撞的远程效应是理解中亚构造格局变化的主要机制。随着其远程效应的北移，位于中亚腹地的准噶尔盆地在周边山脉抬升的影响下，南北缘发生构造活动。基于前人的研究成果，将盆地新生代以来的构造演化概括如下：古新世，因基底断裂复活，盆地北部开始发生逆冲推覆活动；渐新世末期，博格达山脉恢复隆升，古牧地背斜发生构造变形；中新世以来，盆地南缘逐渐形成了三排构造带；上新世末期—更新世以来，北部基底断裂活动，南缘西段和东段分别形成浅层背斜和断裂。目前，由于印度-欧亚板块碰撞远程效应的传播模式仍处于探索阶段，因此需要更多的地质证据来证实它在不同阶段的传播方式以及使盆地发生构造变形的机制。 |
| 关键词: 准噶尔盆地 新生代 构造活动 逆断裂 - 背斜带 |
| DOI：10.7515/JEE221023 |
| CSTR：32259.14.JEE221023 |
| 分类号: |
| 基金项目: |
| 英文基金项目: |
|
| A review of Cenozoic tectonic evolution in the southern margin of Junggar Basin |
|
ZHONG Mengting, ZHANG Rui
|
1. Department of Geology, Northwest University, Xi’an 710069, China
2. College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China
|
| Abstract: |
| Background, aim, and scope The Junggar Basin, situated in the Central Asian hinterland, has experienced significant tectonic evolution since the Paleocene. Over time, the northern margin witnessed mountain uplift, strong thrusting along the basement fault zone, and ongoing tectonic activities, while the Oligocene period saw substantial uplift of the Tianshan Mountains in the southern margin, leading to multi-stage tectonic deformations. Consequently, the dynamic mechanisms underlying basin tectonic deformations during the Cenozoic era vary. Understanding the timing of tectonic activities within the basin since the Cenozoic is crucial for comprehending the Cenozoic tectonic evolution in the basin’s vicinity, Central Asia, and the stress propagation mode resulting from the far-field effects of the India-Eurasia collision since the Neogene. Thus, it is imperative to reconstruct the Cenozoic basin’s tectonic evolution, building upon previous research. Materials and methods This study employs thermochronology, magnetostratigraphy, sedimentology, seismic profiles, and geometric analysis of fault-related folds to elucidate the temporal and spatial distribution of tectonic activity within the basin since the Cenozoic and ascertain the uplift timing of surrounding mountain systems. These methods aid in uncovering the dynamic mechanisms driving tectonic activity within the basin and furthering our comprehension of its Cenozoic tectonic evolution. Results Tectonic activity within the basin commenced around 60 Ma during the Cenozoic, with tectonic deformation manifesting in the southeastern margin during the Oligocene. Subsequently, three sets of reverse fault-anticlinal belts formed in the southern margin of the basin approximately 24—20 Ma, 10—8 Ma, and 4 Ma, respectively, due to lateral compression from the Tianshan Mountains. Discussion Since the Cenozoic, tectonic activity in the basin initially began in the northern margin during the Paleocene, before the India-Eurasia collision activated the Tianshan orogenic belt and transmitted compressive stress to the southern margin. Later, the gradual collision and movement of the Tibetan Plateau led to tectonic activity in the eastern and middle segments of the southern margin during the Late Oligocene to Early Miocene. Compression from the Tianshan Mountains is the primary dynamic mechanism driving basin tectonic activity during the Paleocene and Oligocene—Early Miocene, respectively. Conclusions In the Paleocene, the northern part of the basin experienced tectonic activity due to the Siberian Plate’s extrusion. Subsequently, during the Late Oligocene to Early Miocene, the uplift and northward expansion of the Tibetan Plateau resulted in multi-stage uplift of the Tianshan Mountains, initiating tectonic deformation in the southern margin. Recommendations and perspectives Further research is required to gather additional evidence supporting the dynamics of tectonic activity in the northern margin of the basin. In the western section of the southern margin, chronological data should be employed to precisely determine the initiation of Cenozoic tectonic movements since the end of the Oligocene epoch. The propagation mode of the far-field effect of the India-Eurasia collision remains an ongoing exploration, necessitating additional geological evidence to clarify its stages of expansion. |
| Key words: Junggar Basin Cenozoic tectonic activity thrusting fault-anticline belt |
