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Geological History of WudalianchiRelease date:2021-12-07

Geological History of Wudalianchi

Ancient times
The Wudalianchi area has not yet discovered the remaining geological relics 2.5 billion years ago, and its more ancient geological features are still untestable. About 800 million to 600 million years ago, this area and surrounding areas were on the edge of ancient land, accepting the deposition of sand, mud and other debris from ancient land, consolidating into rock, and volcanic eruption. The remaining lava, later these rocks have undergone a long period of geological processes, and become more rigid. At present, this set of ancient metamorphic rock series is distributed in the deep underground in the east, southeast and southwest of Wudalianchi area.
600 million years ago, the crust in this area rose to become a land, and the ancient metamorphic rock series exposed the surface, suffered long-term weathering and denudation, leaving no thick and new sediments.
Mesozoic period
 248 million years ago ,entering the Mesozoic era, there were multiple magma intrusions and engulfing parts of the ancient metamorphic rock series, forming granites with ages of 205 million years and 136 to 139 million years. Only granites and ancient metamorphic rocks were formed in this area. Department of flat base. The granites in Hubei Yaoquan, Xiaohong Volcano and other places were formed during this period. Since 248 million years, the region has been slowly rising, suffering from weathering and denudation for a long time. Nearly 97.5 million years ago, the surrounding areas of the Songnen Plain (large and small Xing'an Mountains, etc.) rose sharply, while the central part subsided, forming a large depression basin, the Songliao Basin, and gradually forming large lakes. During the period from 97.5 million to 600.2 million years ago (Late Baiping), the Songnen Basin gradually expanded and gradually expanded to the north. At this time, the Wudalianchi area began to sink and was submerged by lake water. It became the northern edge of the Songnen Lake. The mud and sand transported from the mountains are deposited in the lake to form lakeside facies-fluvial and lacustrine facies clastic deposits (sand, mud), which later consolidated into rocks, forming what geology calls the Late Cretaceous Nenjiang Formation clastic sedimentary rocks (Sandstone, mudstone). Because the lake was warmer during this period, aquatic organisms were more developed, and fossils of leaf limbs and ostracods could be seen.
When the Wudalianchi area was at the northern edge of the Songnen Great Lake, due to the difference in paleotopography and subsidence rate, the lake bottom was different in height. In the northeast of Yaoquan Lake, Xiaoping Volcano, Xiaohong Volcano and other places, the topography is high and has been exposed to the water surface, which is an uplift area , Lack of sediments or very thin; while in the west of Wohu Volcano and the fourth team of Wudalianchi Farm in the east, there are two depression areas, with thicker layers of the mid-late Cretaceous deposited, up to 400 meters thick. In the late Cretaceous, the Wudalianchi area rose slowly, the lake gradually became shallower, and finally the lake withdrew; the area became land again, and since the end of the Late Cretaceous, the area has been in the uplifting stage.
Cenozoic period
During the Tertiary Period, this area has been on the rise. 
Since entering the Quaternary period (after 2.43 million years), the northwestern area of Wudalianchi area has a large increase, that is, the Daqing Farm area ,now has a higher terrain and becomes a hilly terrain, while in the south-central and southeast areas, the increase is small and presents a low-lying terrain , forming a basic topographic pattern of high in the northwest and low in the southeast. The Gunnemore River enters the southeastern edge of the area from the northeast and flows to the southwest. The streams in the low-lying areas in the central, south and southeast of the area flow to the southeast. It merges into the Nemore River. Now the area of Daqing Farm is the highest point in the area. The area north of Daqing Farm is a north-sloping terrain. It is a wide valley that opens to the north, with streams flowing northward.
Since this area entered the Quaternary Period, a new geological historical period of volcanic eruption began to appear.
Gelaqiu eruption period
During the period from 2.07 million to 2.1 million years ago, the first phase of volcanic eruption, in the Quaternary period, occurred in the northwestern area of Wudalianchi area. The eruption site should be north of the current Beigelaqiu Volcano, which is a quiet overflow eruption of the shield volcano. Large-scale, lava overflows northward along a wide valley that opens to the north, forming a large area of Gelaqiu lava mesa, up to the present Dongfeng Reservoir. This period of volcanic eruption is the earliest period found in the area, called the Gelaqiu eruption period (the North and South Gelaqiu Volcanoes were not formed during this period, and they formed later).
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