Development of Dzhungar deep fault

The great Dzhungar fault zone extends across the border between Sinkiang and the U.S.S.R., separating the intermontane depression of the Balkhash region and Dzhungaria from the mountain uplift of Dzhungar Alatau. The length of the fault is about 5OO km and the width is several kilometers. On airphotos the fault appears straight, but on a regional scale it is slightly arcuate. The fault is characterized by prolonged development of both vertical and horizontal (right lateral) displacement starting in middle Paleozoic and continuing intermittently to the present. Also during intervals of time, dislocation penetrated the entire thickness of the earth's crust as far as the peridotite layer permitting ultrabasic intrusion. Acidic intrusions, volcanics, and hydrothermally altered rocks also occur along parts of the fault zone. The fault strongly cuts obliquely across Hercynian folding and also alpine dome-block structures. The fault controlled and localized distinctive formations throughout most of post-Precambrian time. A summary of the geologic history of the fault is presented.—L. T. Grose