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沉积物源分析是认识盆山演化的重要途径。天山南麓库车地陷不同剖面的砾岩碎屑、砂岩骨架颗粒、碎屑重矿物组分显示,它们的成熟度及演变时限总体可以类比,表明其成因演化主要受控于物源区——(古)天山的构造活动与造山作用。对碎屑沉积记录的综合分析进一步指示,天山物源总体以“再旋回造山带”类型为特征,其演变细节包括五期:①早三叠世古天山继承石炭纪以来的构造挤压和隆升,物源岩石类型主要为沉积岩、中高级变质岩,以“碰撞造山和褶皱冲断带”及“混合造山带”类型为特征;②中三叠世-中侏罗世构造活动较弱,代表高成熟度的“锆石-金红石-电气石”重矿物组合发育,主要物源岩石类型包括变质岩和酸性火山岩,与“弧造山带”以及“混合造山带”类型关系密切;③晚侏罗世-白垩纪,天山开始新一轮的构造挤压隆升,物源岩石类型复杂;④第三纪(特别是中新世)构造挤压和隆升活动加强,稳定性极差的碎屑“角闪石- 辉石”组合增多,物源组分东西分异明显,西部沉积岩相对较多,物源构造属性趋向“碰撞造山和褶皱冲断带”;东部结晶岩相对较多,物源构造属性复杂或以“混合造山带”类型为特征;⑤上新世南天山强烈隆升和向南推进,与前一阶段相比沉积岩物源增多,但物源构造属性基本同上。第④⑤两个阶段砾岩层和不稳定碎屑组?
Sediment source analysis is an important way to recognize basin evolution. The conglomerate debris, sandstone skeleton particles and detrital heavy mineral components in different sections of the Kuqa subsidence in the south of Tianshan Mountains show that their maturity and evolution period can be generally analogized, indicating that their genetic evolution is mainly controlled by the source region - - (Ancient) Tianshan tectonic activities and orogenic effects. The comprehensive analysis of detrital sedimentary records further indicates that the Tianshan provenances are generally characterized by the type of “re-orogenic orogenic belt” and include five stages of evolution: (1) the structural compression and uplift of the Early Triassic Paleontology since the Carboniferous The source rocks are mainly sedimentary rocks and middle- and high-grade metamorphic rocks characterized by “collision orogeny and fold-thrust belt” and “mixed orogenic belt” types; ② Middle Triassic-Middle Jurassic tectonic activity is weak, representing The maturity of the “zircon - rutile - tourmaline” heavy mineral assemblage development, the main source rock types include metamorphic rocks and acidic volcanic rocks, and the “arc orogenic belt” and “mixed orogenic belt” types are closely related; ③ late Jurassic During the Cretaceous, the Tianshan Mountains began a new round of tectonic extrusion and uplifting, resulting in complicated source rock types. (4) Tertiary (especially Miocene) tectonic crust with enhanced crustal and uplift activity and poor stability The assemblages of “amphibole-pyroxene” increase with obvious differentiation of the provenance components and relatively large amount of sedimentary rocks in the west, with tectonic provenances tending to “collisional orogeny and fold-thrust belt”; there are relatively many eastern crystalline rocks, Complexity of construction attributes or “mixed Orogen ”type feature; the ⑤ Pliocene southern Tianshan uplift and southward, increased compared to the previous phase sedimentary provenance, but the provenance tectonic attributes Same as above. ④ ④ ⑤ two stages of conglomerate layer and unstable debris group?