|
Guzhangian
The Guzhangian is an uppermost stage of the Miaolingian Series of the Cambrian. It follows the Drumian Stage and precedes the Paibian Stage of the Furongian Series. The base is defined as the first appearance of the trilobite '' Lejopyge laevigata'' around million years ago. The Guzhangian-Paibian boundary is marked by the first appearance of the trilobite '' Glyptagnostus reticulatus'' around million years ago. The name Guzhangian is derived from Guzhang County, Hunan Province, China. GSSP The GSSP is defined in the Huaqiao Formation in Hunan. The precise base of the Guzhangian is a limestone layer 121.3 m above the base Huaqiao Formation (花桥组) at the Louyixi section (), where '' Lejopyge laevigata'' has its first appearance. Paleogeography It is assumed that in the Guzhangian the distance between the Earth and the Moon was 370,180 ± 1220 km (today, for comparison, it is 384,000 km). The length of an earthly day at that time was about 21.58 hours. Major events ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furongian
The Furongian is the fourth and final epoch and series of the Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov .... It lasted from to million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three stages: the Paibian, Jiangshanian and the unnamed Cambrian Stage 10, 10th stage of the Cambrian. History and naming The Furongian was also known as the Cambrian Series 4, and the name replaced the older term Upper Cambrian and equivalent to the local term Hunanian. The present name was ratified by the International Commission on Stratigraphy in 2003. () means 'lotus (genus), lotus' in Mandarin and refers to Hunan which is known as the "lotus state". Definition The lower boundary is defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miaolingian
The Miaolingian is the third Series of the Cambrian Period, and was formally named in 2018. It lasted from about to million years ago and is divided in ascending order into 3 stages: the Wuliuan, Drumian, and Guzhangian. The Miaolingian is preceded by the unnamed Cambrian Series 2 and succeeded by the Furongian series. It is named after the Miaoling Mountains in southeastern Guizhou Province, China. Definition A number of proposals for fossils and type sections were made before it was formally ratified in 2018. The most promising fossil markers were seen to be the respective first appearances of either trilobite species ''Ovatoryctocara granulata'' or ''Oryctocephalus indicus'', which both have an age close to million years ago. After some deliberation, the FAD of ''Oryctocephalus indicus'' was chosen to be the lower boundary marker, and the GSSP was placed in the Kaili Formation, Wuliu-Zengjiayan, Guizhou, China. The Miaolingian-Furongian boundary has the same definition a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guzhang
Guzhang County ( zh, t=古丈縣 , s=古丈县 , p=Gǔzhàng Xiàn) is a Counties of the People's Republic of China, county of Hunan, Hunan Province, China. The county is the List of County-level divisions of Hunan by population, 2nd least populous administrative unit of the counties or county-level cities (after Shaoshan, Shaoshan City) in the province, it is under the administration of Xiangxi Tujia and Miao Autonomous Prefecture, Xiangxi Autonomous Prefecture. Located in the northwest of Hunan and in the east of Xiangxi Prefecture, the county is bordered to the north by Yongshun County, to the east by Yuanling County, to the south by Luxi County, Hunan, Luxi County and Jishou, Jishou City, and to the west by Baojing County. Guzhang County covers an area of , and as of 2015, it had a registered population of 143,182 and a resident population of 131,900.about the population of Guzhang County in 2015, according to the Statistical Communiqué of Guzhang County on the 2015 National ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guzhang County
Guzhang County ( zh, t=古丈縣 , s=古丈县 , p=Gǔzhàng Xiàn) is a county of Hunan Province, China. The county is the 2nd least populous administrative unit of the counties or county-level cities (after Shaoshan City) in the province, it is under the administration of Xiangxi Autonomous Prefecture. Located in the northwest of Hunan and in the east of Xiangxi Prefecture, the county is bordered to the north by Yongshun County, to the east by Yuanling County, to the south by Luxi County and Jishou City, and to the west by Baojing County. Guzhang County covers an area of , and as of 2015, it had a registered population of 143,182 and a resident population of 131,900.about the population of Guzhang County in 2015, according to the Statistical Communiqué of Guzhang County on the 2015 National Economic and Social Development - ()guzhang.gov.cno/ref> The county has 7 towns under its jurisdiction, and the county seat is Guyang ().the divisions of Guzhang County in 2015, acco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paibian
The Paibian is the lowest stage of the Furongian Series of the Cambrian System. The Paibian is also the first age of the Furongian Epoch of the Cambrian Period. It follows the Guzhangian ( Miaolingian series of the Cambrian) and is succeeded by the Jiangshanian Stage. The base is defined as the first appearance of the trilobite '' Glyptagnostus reticulatus'' around million years ago. The top, or the base of the Jiangshanian is defined as the first appearance of the trilobite '' Agnostotes orientalis'' around million years ago. GSSP The name is derived from Paibi, a village in Hunan, China. The GSSP is defined in the "Paibi section" ( Wuling Mountains, Huayuan County), an outcrop of the Huaqiao Formation (花桥组). The base is the first occurrence of '' Glyptagnostus reticulatus'' which is 396 m above the base of the Huaqiao Formation at the type locality (). Major events At the turn of the Guzhangian and Paibian ages, an extinction event occurred that reduced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Ages
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardised international units of geological time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precisely de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Geochronology
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in life on Earth; prior to the Period, the majority of living organisms were small, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly increase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new convergent plate boundaries and continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in life on Earth; prior to the Period, the majority of living organisms were small, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it was not until the Cambrian that fossil diversity seems to rapidly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drumian
The Drumian is a stage of the Miaolingian Series of the Cambrian. It succeeds the Wuliuan and precedes the Guzhangian. The base is defined as the first appearance of the trilobite '' Ptychagnostus atavus'' around million years ago. The top is defined as the first appearance of another trilobite '' Lejopyge laevigata'' around million years ago. GSSP The GSSP is defined in the ''Drumian section'' () in the Drum Mountains, Millard County, Utah, United States. The stage was also named after the Drum Mountains. The section is an outcrop of the Wheeler Formation, a succession of calcareous shales. The precise base of the Drumian is a laminated limestone above the base of the Wheeler Formation. Major events The Cambrian Drumian carbon isotope excursion (DICE) event is associated with the beginning of this age. The cause of this event was the shallowing of anoxic deep waters simultaneously with their transgression. DICE hampered the recovery of reef ecosystems already affected by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steptoean Positive Carbon Isotope Excursion
The Steptoean positive carbon isotope excursion (SPICE) is a global chemostratigraphic event which occurred during the upper Cambrian period between 497 and 494 million years ago. This event corresponds with the ICS Guzhangian-Paibian Stage boundary and the Marjuman-Steptoean stage boundary in North America. The general signature of the SPICE event is a positive δ13C excursion, characterized by a 4 to 6 ‰ (per mille) shift in δ13C values within carbonate successions around the world. SPICE was first described in 1993, and then named later in 1998. In both these studies, the SPICE excursion was identified and trends were observed within Cambrian formations of the Great Basin of the western United States. Age The age of the SPICE is dated to between 497 and 494 MA, where it has primarily been identified through the use of relative dating and biostratigraphy. The onset of SPICE is generally accepted to correspond with the second wave of the End-Marjuman Biomere Extinction, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
