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Tiaojishan Formation
The Tiaojishan Formation is a geological formation in Hebei and Liaoning, People's Republic of China, dating to the middle-late Jurassic period (Bathonian-Oxfordian (stage), Oxfordian stages). It is known for its Lagerstätte, exceptionally preserved fossils, including those of Paleobotany, plants, insects and vertebrates. It is made up mainly of pyroclastic rock interspersed with basic volcanic and sedimentary rocks. Previously, the Tiaojishan Formation was grouped together with the underlying Haifanggou Formation (also known as the Jiulongshan Formation) as a single "Lanqi Formation." The Tiaojishan Formation forms a key part of the Yanliao Biota assemblage, alongside the Haifanggou Formation. Age Using Argon–argon dating, Wang and colleagues in 2005 dated part of the Tiaojishan Formation to about 160 million years ago, the beginning of the Oxfordian (stage), Oxfordian stage, the first stage of the Upper Jurassic epoch. In 2006, a study by Liu and colleagues used Zircon#Radio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Qinglong Manchu Autonomous County
Qinglong Manchu Autonomous County (, Manchu: ) is a Manchu autonomous county in northeastern Hebei province, China, bordering Liaoning Province to the north and east and located in the eastern part of the Yan Mountains. It is under the administration of the prefecture-level city of Qinhuangdao, and, , had a population of 520,000 residing in an area of . Bordering county-level divisions are: Lingyuan and Jianchang County (Liaoning) to the north, Liaoning's Suizhong County and Qinhuangdao city proper to the east, Qian'an and Lulong County to the south, and Kuancheng Manchu Autonomous County and Qianxi County to the west. During the 1976 Tangshan earthquake 180,000 buildings in Qinglong collapsed, but no fatalities occurred. Administrative divisions Qinglong administers 1 subdistrict, 11 towns and 14 townships: Climate Qinglong has a monsoon-influenced, humid continental climate (Köppen ''Dwa''), with long, cold, and very dry winters, and hot, rainy summers. Spring a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humidity
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog to be present. Humidity depends on the temperature and pressure of the system of interest. The same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is the dew point. The amount of water vapor needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass. The amount of water vapor contained within a parcel of air can vary significantly. For example, a parcel of air near saturation may contain 8 g of water per cubic metre of air at , and 28 g of water per cubic metre of air at Three primary measurements of humidity are widely employed: abso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperateness
In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout the year and more distinct seasonal changes compared to tropical climates, where such variations are often small; they usually differ only in the amount of precipitation. In temperate climates, not only do latitudinal positions influence temperature changes, but various sea currents, prevailing wind direction, continentality (how large a landmass is) and altitude also shape temperate climates. The Köppen climate classification defines a climate as "temperate" C, when the mean temperature is above but below in the coldest month to account for the persistence of frost. However, some adaptations of Köppen set the minimum at . Continental climates are classified as D and considered to be varieties of temperate climates, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subtropics
The subtropical zones or subtropics are geographical and climate zones immediately to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° to 40° north and south. The horse latitudes lie within this range. Subtropical climates are often characterized by hot summers and mild winters with infrequent frost. Most subtropical climates fall into two basic types: humid subtropical (Köppen climate classification: Cfa/Cwa), where rainfall is often concentrated in the warmest months, for example Southeast China and the Southeastern United States, and dry summer or Mediterranean climate (Köppen climate classification: Csa/Csb), where seasonal rainfall is concentrated in the cooler months, such as the Mediterranean Basin or Southern California. Subtropical climates can also occur at high elevations within the tropics, such as in the southern end of the Mexican Plateau an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zircon
Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of the range of substitution in zircon is (Zr1–y, REEy)(SiO4)1–x(OH)4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green. The name derives from the Persian ''zargun'', meaning "gold-hued". This word is changed into " jargoon", a term applied to light-colored zircons. The English word "zircon" is derived from ''Zirkon'', which is the German adaptation of this word. Yellow, orange, and red zircon is also known as " hyacint ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age. In the past, ''Malm'' was also used to indicate the unit of geological time, but this usage is now discouraged to make a clear distinction between lithostratigraphic and geochronologic/chronostratigraphic units. Subdivisions The Late Jurassic is divided into three ages, which correspond with the three (faunal) stages of Upper Jurassic rock: Paleogeography During the Late Jurassic Epoch, Pangaea broke up into two supercontinents, Laurasia to the north, and Gondwana to the south. The result of this break-up was the emergence of the Atlantic Ocean, which initially was relatively narrow. Life forms This epoch is well known for many famous types of dinosaurs, such as the sauropods, the theropods, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argon–argon Dating
Argon–argon (or 40Ar/39Ar) dating is a radiometric dating method invented to supersede Potassium-argon dating, potassiumargon (K/Ar) dating in accuracy. The older method required splitting samples into two for separate potassium and argon measurements, while the newer method requires only one rock fragment or mineral grain and uses a single measurement of isotopes of argon, argon isotopes. 40Ar/39Ar dating relies on neutron irradiation from a nuclear reactor to convert a stable form of potassium (39K) into the radioactive 39Ar. As long as a standard of known age is co-irradiated with unknown samples, it is possible to use a single measurement of argon isotopes to calculate the 40K/40Ar* ratio, and thus to calculate the age of the unknown sample. 40Ar* refers to the radiogenic 40Ar, i.e. the 40Ar produced from radioactive decay of 40K. 40Ar* does not include atmospheric argon adsorbed to the surface or inherited through diffusion and its calculated value is derived from measuring t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yanliao Biota
The Yanliao Biota is the name given to an assembly of fossils preserved in northeastern China from the Middle to Late Jurassic.Xu, X., Zhou, Z., Sullivan, C. and Wang, Y., 2017. The Yanliao Biota: a trove of exceptionally preserved Middle-Late Jurassic terrestrial life forms. Terrestrial Conservation Lagerstätten. Dunedin Academic Press, London, pp.131-167. It includes fossils from the Tiaojishan Formation and Haifanggou Formation. This spans approximately 165 to 150 million years ago. Like the Jehol Biota, these deposits are composed of alternating layers of volcanic tuff and sediment, and are considered Lagerstätte. These are some of the best preserved Jurassic fossils in the world, and include many important dinosaur, mammal, salamander, insect and lizard specimens, as well as plants. History The first fossils of the Yanliao Biota were found around 1998 near the village of Daohugou in Inner Mongolia. The following year, the first two important specimens were discovered, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rock
Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedimentation is any process that causes these particles to settle in place. Geological detritus originates 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 wasting, mass movement, which are called agents of denudation. Biological detritus is 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 when dissolved minerals precipitate from aqueous solution, water solution. The sedimentary rock cover of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Rock
Pyroclastic rocks are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyroclasts. Pyroclastic rocks are a type of volcaniclastic deposit, which are deposits made predominantly of volcanic particles. 'Phreatic' pyroclastic deposits are a variety of pyroclastic rock that forms from volcanic steam explosions and they are entirely made of accidental clasts. 'Phreatomagmatic' pyroclastic deposits are formed from explosive interaction of magma with groundwater. The word ''pyroclastic'' is derived from the Greek , meaning fire; and , meaning broken. Unconsolidated accumulations of pyroclasts are described as tephra. Tephra may become lithified to a pyroclastic rock by cementation or chemical reactions as the result of the passage of hot gases (fumarolic alteration) or groundwater (e.g. hydrothermal alteration and diagenesis) and burial, or, if it is emplaced at temperatures so hot that the soft gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleobotany
Paleobotany or palaeobotany, also known as paleophytology, is the branch of botany dealing with the recovery and identification of plant fossils from geological contexts, and their use for the biological reconstruction of past environments ( paleogeography), and the evolutionary history of plants, with a bearing upon the evolution of life in general. It is a component of paleontology and paleobiology. The prefix ''palaeo-'' or ''paleo-'' means "ancient, old", and is derived from the Greek adjective , . Paleobotany includes the study of land plants, as well as the study of prehistoric marine photoautotrophs such as photosynthetic algae, seaweeds or kelp. A closely related field is palynology, which is the study of fossilized and extant spores and pollen. Paleobotany is important in the reconstruction of ancient ecological and climate systems, known as paleoecology and paleoclimatology respectively. It is fundamental to the study of green plant development and evolution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
