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Shanxi Rift System
The Shanxi Rift System or Fen–Wei Rift System is a zone of active extensional tectonics that forms the eastern margin of the Ordos Block in northern China. The zone extends for at least and runs south-southwest to north-northeast. The individual rift basins that make up the rift system have an overall en echelon geometry, consistent with a right lateral sense of strike-slip displacement across the zone. The basins contain a thick sedimentary sequence of Neogene age, which ranges from in thickness. The rift system is continuous with the Weihe Basin to the southwest, which became active during the Paleogene. Rupture of the major normal faults that bound the Weihe and Shanxi rift basins has caused many large and damaging historical earthquakes, including the 1303 Hongdong (>200,000 deaths), 1556 Shaanxi (830,000 deaths), 1626 Lingqiu (>5,200 deaths), 1695 Linfen (>52,600 deaths) and 1815 Pinglu (>13,000 deaths) events. Nomenclature The Shanxi Rift System is named for the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordos Block
The Ordos Block is a crustal block, that forms part of the larger North China Block (NCB). It is surrounded by active fault systems and has been a distinct block since at least the Mesozoic. It is bordered to the west by the Alxa Block, the westernmost part of the NCB, to the south by the Qinling orogenic belt, to the north by the Yanshan-Yinshan orogenic belt, part of the Central Asian Orogenic Belt and to the east by the Taihangshan mountain range, which forms part of the Trans-North China Orogen. The block is currently stable and large earthquakes are restricted to the bordering fault zones. It has been suggested that the block is currently undergoing anti-clockwise rotation with respect to the Eurasian Plate, as a result of the ongoing eastward spreading of the Tibetan Plateau, although this view has been challenged. Extent The Ordos Block is a roughly rectangular fault-bounded part of the larger North China Block, which itself closely matches the extent of the Paleoproteroz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xi'an
Xi'an ( , ; ; Chinese: ), frequently spelled as Xian and also known by #Name, other names, is the list of capitals in China, capital of Shaanxi, Shaanxi Province. A Sub-provincial division#Sub-provincial municipalities, sub-provincial city on the Guanzhong, Guanzhong Plain, the city is the third most populous city in Western China, after Chongqing and Chengdu, as well as the most populous city in Northwest China. Its total population was 12,952,907 as of the 2020 census. The total urban population was 9.28 million. Since the 1980s, as part of the China Western Development, economic growth of inland China especially for the central and northwest regions, Xi'an has re-emerged as a cultural, industrial, political and educational centre of the entire central-northwest region, with many facilities for research and development. Xi'an currently holds sub-provincial city in the People's Republic of China, sub-provincial status, administering 11 districts and 2 counties. In 2020, Xi'a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coulomb Stress Transfer
Coulomb stress transfer is a seismic-related geological process of stress changes to surrounding material caused by local discrete deformation events. Using mapped displacements of the Earth's surface during earthquakes, the computed Coulomb stress changes suggest that the stress relieved during an earthquake not only dissipates but can also move up and down fault segments, concentrating and promoting subsequent tremors. Importantly, Coulomb stress changes have been applied to earthquake-forecasting models that have been used to assess potential hazards related to earthquake activity. Coulomb stress change The Coulomb failure criterion requires that the Coulomb stress exceeds a value σf defined by the shear stress τB, normal stress σB, pore pressure p, and coefficient of friction μ of a failure plane, such that It is also often assumed that changes in pore fluid pressure induced by changes in stress are proportional to the normal stress change across the fault plane. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yellow River
The Yellow River or Huang He (Chinese: , Mandarin: ''Huáng hé'' ) is the second-longest river in China, after the Yangtze River, and the sixth-longest river system in the world at the estimated length of . Originating in the Bayan Har Mountains in Qinghai province of Western China, it flows through nine provinces, and it empties into the Bohai Sea near the city of Dongying in Shandong province. The Yellow River basin has an east–west extent of about and a north–south extent of about . Its total drainage area is about . The Yellow River's basin was the birthplace of ancient Chinese, and, by extension, Far Eastern civilization, and it was the most prosperous region in early Chinese history. There are frequent devastating floods and course changes produced by the continual elevation of the river bed, sometimes above the level of its surrounding farm fields. Etymology Early Chinese literature including the '' Yu Gong'' or ''Tribute of Yu'' dating to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zhongtiao Mountains
The Zhongtiao Mountains () are a major mountain range located in the south of China’s Shanxi Province. Running from north east to south west the range connects with the Taihang Mountains to the east, overlooks the Yellow River to the south and faces the Fen River valley to the north west. To the west the mountains are separated from the Yellow River by the Qin Mountains. The range extends for approximately with the highest peak rising to above sea level. During the Second Sino-Japanese War (1937–1945) the Japanese army advanced west into Shaanxi and encircled this area many times in what was known as the Zhongtiao Mountains Campaign. The Zhongtiao Mountains were one of the birth places of Taoism Taoism (, ) or Daoism () refers to either a school of philosophical thought (道家; ''daojia'') or to a religion (道教; ''daojiao''), both of which share ideas and concepts of Chinese origin and emphasize living in harmony with the '' Ta ... in Northern China and an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Environment
In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be formed after lithification, if the sediment is preserved in the rock record. In most cases, the environments associated with particular rock types or associations of rock types can be matched to existing analogues. However, the further back in geological time sediments were deposited, the more likely that direct modern analogues are not available (e.g. banded iron formations). Types of depositional environments Continental * – type of Fluvial deposit. Caused by moving water in a fan shape (Alluvial Fan) and containing mostly impermeable and nonporous sediments well sorted. * . Often in deserts and coastal regions and well sorted, large scale cross-beds * – processes due to moving water, mainly streams. Common sediments are grav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacustrine Deposits
Lacustrine deposits are sedimentary rock formations which formed in the bottom of ancient lakes. A common characteristic of lacustrine deposits is that a river or stream channel has carried sediment into the basin. Lacustrine deposits form in all lake types including rift graben lakes, oxbow lakes, glacial lakes, and crater lakes. Lacustrine environments, like seas, are large bodies of water. They share similar sedimentary deposits which are mainly composed of low-energy particle sizes. Lacustrine deposits are typically very well sorted with highly laminated beds of silts, clays, and occasionally carbonates. In regards to geologic time, lakes are temporary and once they no longer receive water, they dry up and leave a formation. Lake types Lacustrine deposits can form in every variety of basins found in nature. How each basin originates is where the distinction between lacustrine deposit types stem. Rift graben lakes are formed from crustal stretching also known as rifting. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluvial Processes
In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluvioglacial is used. Fluvial processes Fluvial processes include the motion of sediment and erosion or deposition on the river bed. The movement of water across the stream bed exerts a shear stress directly onto the bed. If the cohesive strength of the substrate is lower than the shear exerted, or the bed is composed of loose sediment which can be mobilized by such stresses, then the bed will be lowered purely by clearwater flow. In addition, if the river carries significant quantities of sediment, this material can act as tools to enhance wear of the bed ( abrasion). At the same time the fragments themselves are ground down, becoming smaller and more rounded (attrition). Sediment in rivers is transported as either bedload (the coarser frag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alluvial
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is typically geologically young and is not consolidated into solid rock. Sediments deposited underwater, in seas, estuaries, lakes, or ponds, are not described as alluvium. Floodplain alluvium can be highly fertile, and supported some of the earliest human civilizations. Definitions The present consensus is that "alluvium" refers to loose sediments of all types deposited by running water in floodplains or in alluvial fans or related landforms. However, the meaning of the term has varied considerably since it was first defined in the French dictionary of Antoine Furetière, posthumously published in 1690. Drawing upon concepts from Roman law, Furetière defined '' alluvion'' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies ( marine snow). Sedimentation may also occur as dissolved minerals precipita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
