Uplift-denudation in the south margin and its sedimentary response in the southern Yili basin: Analysis apatite fission track method
伊犁盆地南缘隆升剥蚀及其盆地南部的沉积——利用磷灰石裂变径迹分析

14 apatite samples, of which 10 samples were collected in the midwest segment and 4 samples were collected in the east segment, are analyzed from the south denudation area of Yili basin. The characteristics of apparent age and its relationship with altitude, single grain age, confined fission-track length distribution of apatite fission track show that these samples have annealinged in some extent but have not suffered from obvious regional thermal event. The simulation of normal thermal history by confined fission-track demonstrates that there are three tectonic evolution stages during the Mesozoic-Cenozoic in the south margin area of Yili basin, quick uplift stage in Triassic to the Later Jurassic period, relatively stabilize stage in Cretaceous to Paleogene Period and quick uplift stage in neotectonic period. The tectonic evolution is different a little between the east and the west segment in Yili basin. The west segment uplift early which started intensively from the Early Triassic period by analyzing samples to show that here was far from borderline of archetype basin, when the east segment maybe still accepted sediment until the end of the Middle Jurassic. The south borderline of Jurassic archetype basin strides at least Daban coal mine where mid-Xiashanyao Formation of the Jurassic reveals. Stable phase in the east segment which was 50~60Ma is shorter than in west segment which was 100Ma. The neotectonic strong movement was early in the east segment to uplift from 38Ma. The characteristics of sediment facies in the south basin and the age of Electron Spin Resonance (ESR) ages in Neocene or Quaternary demonstrate that there is obvious response between sediment and tectonic movement. The sediment is coarse-grained when uplift quickly around basin, and is fine-grained or absent in relative stable phase.