natural conditions
Geology and Geomorphology The province's geotectonics are located in the southern margin of China-Korea parapet, the eastward extension of Kunlun Qinling geosyncline and the northern margin of Yangtze parapet. The geological structure of the province is complex, and the characteristics of the Sino-Korean paraplatform are that the basement strata are closely linear folds, and the caprock mainly reflects rhombic fault blocks or widely spread fold structures. The Kunlun Qinling geosyncline is characterized by strong linear folds and strike faults. Mineral resources are rich and diverse. Bauxite, coal, refractory clay and pyrite were formed in the late Paleozoic. The Mesozoic Yanshan movement produced gold, molybdenum, fluorite, silver, lead, zinc, magnesium, etc. Cenozoic Himalayan movement formed oil, natural gas, oil shale and trona. There are 102 kinds of minerals found, among which trona, molybdenum and crocidolite rank first in China. Among the top 10 in China are aluminum, tungsten, gold, antimony, coal, petroleum, perlite, bentonite and silica. In addition, there are abundant rare metals.
The eastern plain is a part of the North China Plain, which is mainly formed by alluvial rivers of the Yellow River, Huai River and Wei River, and the ancient alluvial fan of the Yellow River is its core. It is also the earliest exposed area in North China Plain, with an altitude of 40 ~100 meters. Alluvial fans of the Yellow River have been in a declining stage since Tertiary, and thick alluvium has been deposited. Since the upper Pleistocene, the accumulation of the Yellow River has played a leading role. Due to the three-time decline and relative stability of the crust since the Upper Pleistocene, three periods of overlapping accumulation of ancient alluvial fans of the Yellow River were formed. In the third phase, the development of the ancient alluvial fan of the Yellow River expanded forward every time, so the scale increased every time. Especially in the late stage. In the east of Henan Province, an extensive alluvial fan-shaped plain is formed with Huayuankou-Dongbatou Yellow River as the ridge axis, with flat terrain and abundant groundwater, which is the main agricultural area in the province. However, the riverbed of the Yellow River is raised every year, forming a spine in the area, which is obviously inclined to the northeast and southeast. In history, many floods and diversions of the Yellow River have occurred here, leaving behind many old embankments, slow dunes and trough depressions, which have caused unfavorable conditions such as waterlogging, sandstorm and saline-alkali in some areas and made agricultural production unstable in the plain.