Eruption of mud volcanoes on northern slope of the Tianshan Mountains in Xinjiang Uighur Autonomous Region, Northwest China

April 26th,2010 - April 30th,2010

This field trip offers the unique opportunity to visit several areas with petroleum related mud volcanoes on the northern piedmont of the Tianshan Mountains that are standing as the southern margin of the Junggar Basin in Xinjiang Uighur Autonomous Region of northwest China. As one of the largest Mesozoic-Cenozoic sedimentary basins in Northwest China, the Junggar Basin in north Xinjiang is enriched with coals, asphalts, crude oils and natural gases. This area is dominated by a inland arid climate with high evaporation rate, abundant sunshine and large temperature disparity between day and night, and also sharp seasonal changes with hot summer (as high as 45oC) and cold winter (as low as -35oC). This region has poor green covers except for some oasis areas, which are normally located along rivers or streams from the Tianshan Mountains on south.

Dushanzi Anticline with reddish Tertiary sequences, the reddish rock was bleached into green-yellowish by hydrocarbons from the mud volcanoes

One crater of the Dushanzi Mud Volcanoes

There are 3 or 4 rows of anticline folds in northern front of the Tianshan Mountains faced to the Junggar Basin on north because of the northward thrusting of the high mountains. Some of the anticlines occurred with normal faults in their axis, which provide pathways for eruption of mud volcanoes and hydrocarbon seepages. Many petroleum related mud volcanoes have been discovered mainly in four areas including the Jiangjungou Valley, Dushanzi Hill, Aiqugou Valley and Sikeshu Slope etc. from east to west. This field trip will mainly offer the following sites;

Eruption of oil-gas-mud from the No 1 drilling well

Twin Mud Volcanoes in the Aiqugou Valley, left one has been broken by heavy precipitation in October 2007

Site 1, Dushanzi Mud Volcano. The Dushanzi Hill, located in south Dushanzi Town, appears as a single yellowish hill with an elevation of about 940 meters above sea level and is the main part of the Dushanzi anticline. There is a normal fault along the crest of the Dushanzi anticline. The crude oil seepages were discovered in 1950’s and is still visible at present in the core of the anticline. The reddish Tertiary sequences at surface were bleached because of hydrocarbon-induced alteration. A large mud volcano crater with a diameter of 115 m is found on the top of the hill, and numerous small mud volcano vents and craters in various sizes are active still erupting with mud, water and gases at present. In addition, there is one partially artificial crater on the north slope of the hill as disused oil well. This well used to the first drilling well in the Dushanzi oilfields.

Site 2, Aiqugou Twin Mun Volcano. There are two volcanic cones with similar size and height standing on the left bank of Aiqugou River flowing from the Tianshan Mountain at south to the basin at north. These cones were composited by erupted mud with oils and gases. One of them was broken since heavy rainfall in October 2007. However, these two volcanoes are still erupting right now.

Site 3, Sikeshu Group of Mud Volcanoes. There are more than 50 eruption craters and holes with oil, gas, water and mud within a two square kilometers area. The whole area is very distinguished in rocks and soils colors from the surrounding rocks because of the ongoing bleaching effect. The craters are different size from 2*2 m2 to less than a broad bean. Some of them are erupting with gray mud and some others with reddish mud.

Site 4, Tianchi on Bogeda Mountains. Tianchi, or the Heavenly Pond, is a typical glacier lake on the high slopes with a natural dam of glacier deposits. The lake water is about 4.9 square kilometers and the water surface is about 1970 m above sea level. The lake is dubbed "the Pearl of the Tianshan Mountains" in the Tianshan Mountains in the Xinjiang Uygur Autonomous Region.

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