准噶尔盆地南缘苍房沟群物源分析

Provenance analysis of Cangfanggou Group in the southern margin of Junggar Basin

根据砾岩成分、碎屑组成、主量元素及重矿物组合特征，探讨准噶尔盆地南缘苍房沟群物源特征及物源区。砾岩成分分析表明：伊林哈比尔尕山的石炭系地层是准噶尔南缘西段苍房沟群的主要物源区，而博格达山是准噶尔南缘东段前缘坳陷的物源区。砂岩骨架成分分析表明：北天山作为准噶尔南缘前陆坳陷主要物源区曾存在，但持续时间很短；博格达山北缘的石炭系柳树沟组岩层为准噶尔南缘东段前缘坳陷的主要物源。主量元素测定表明：下苍房沟群岩石样品以火山岩为主要物源区特征，其物源很有可能来自南部伊林哈比尔尕山中石炭系的火山岩；而上苍房沟群以混杂物源区为特征，表明早三叠世隆升的博格达山已成为其物源区。盆地南缘西段以低级变质岩和中酸性岩浆岩的重矿物组合为特征，表明北天山隆起是其主要物源区；东段以中酸性岩浆岩和中高级变质岩重矿物组合为特征，综合考虑其物源区应为南部的博格达山。

Based on comprehensive analytical methods of conglomerate constituent, detrital composition, major element and heavy mineral, the characteristics and provenance of stones of Cangfanggou Group in the southern margin of Junggar Basin are studied. The analysis of conglomerate component of Cangfanggou Group shows that carboniferous formation of Yilinhabierga Mountain was the source areas of the Cangfanggou Group in the west, and the Bogda Mountain was the source areas of frontal depression in the east. The analysis of sand matrix component of Cangfanggou Group shows that the northern Tianshan Area was the source area of frontal depression in the past, but in a short time. The carboniferous Liushugou Formation in the northern area of the Bogda Mountain was the main source area of frontal depression. The measurement of the major element shows that the rock samples of the lower Cangfanggou Group are the main volcanic features of the source area, and the source is likely to come from the carboniferous volcanic rock of the southern Yilinhabierga Mountain. The upper Cangfanggou Group is with mixed characteristics of the source area and something shows that early Triassic swelling Bogda Mountain has become the source area. The western part of the southern margin of Junggar Basin has genetic features of low-grade rock and medium-acidic magmatite, which show that the uplift of the northern Tianshan was the main source areas. The eastern part has genetic features of medium-acidic magmatite and mid-high- grade rock. It is considered comprehensively that the source areas is the southern Bogda Mountain.