The granulite facies rocks were formed at P=7.91 10.70×10 8Pa,T=717 807℃,a geothermal gradient of approximately 21 25℃/km and burial depths of roughly 29 39 km; so the rocks belong to middle pressure granulite facies.
According to several geothermobarometers and metamorphic reactions, it can be estimated that the P T conditions of the main stage are: T =520℃～580℃, P =1 2～1 4GPa, the geothermal gradient is 12℃/km, belonging to transitional type of high pressure.
The melange slice in Kuhai-Saishitang tectonic melange belt hassimultaneously subjected a middle-high pressure metamorphism of greenschist facies and astrong ductile shear deformation. According to a calculation. it is a product under suchmetamorphic conditions of p= 0.5～0.7Gpa, T = 400℃～450℃ and geothermal gradient of16℃～22℃/ Km.
Metanorphic condition is P H_2O=5kb,T= 350℃. Me tamorphic facies belong to“low green schist facies to low hornblende facies”. Geothermal gradient is 17°～20℃/km.
Geo thermal gradient of eastern basins is high, which is generally higher than 3.6℃/100m, and the highest can reach 5.56℃/100m. Eastern basins mainly are faulted basins in type, where the thickness of crust obviously decreases and magmatic activity is intense. These indicate that there is an intensive regional structural thermal event.
The geo thermal gradient difference between western and eastern basins of North China in late Mesozoic shows that geodynamic background is different in eastern and western basins.
However, the western basins are of depression basins, the geo thermal gradient of them is generally lower than 3℃/100m, i.e. lower than the eastern basins. In western basins thickness of crust increases and magmatic activity is weak.
The granulite facies rocks were formed at P=7.91 10.70×10 8Pa,T=717 807℃,a geothermal gradient of approximately 21 25℃/km and burial depths of roughly 29 39 km; so the rocks belong to middle pressure granulite facies.
Recent temperature-pressure(pT)calculations suggest that the pT conditions of garnet peridotites were probably1100～1200℃and6.5～8.0GPa with a geothermal gradient of than5℃/km or less,i. e. in the forbidden-zone of metamorphism in the Earth.
According to the data obtained from such geothermometers and geobarometers as Opx-Cpx, Opx-Hb, Cpx-Hb, Hb-Pl, Sca-Pl and Fe-Ti ovides, it has been determined that the temperature of the principle metamorphic phase was 720—810℃, the pressure 0.5 GPa and fO_2 10~(-15.5), showing a geothermal gradient of 41—46℃/km, and thus the rocks belong to "low-temperature" and lowpressure granulite facies.
The characteristics of the volacnic gases, microseismic activities and the geothermic gradient etc, clearly show that Wudalianchi volcanoes are still active.
The carbon isotopic characteristics of natural gas are not only affected by the gas source and maturity of the source rock, but also are related to the accumulation condition and geothermal gradient in a basin.
While, the geothermal gradient and the weak tectonic geothermal event of the Early Yanshan Movement provided necessary heat for the maturation of source rock in coal-bearing strata of the Middle and Lower Jurassic.
The upward degradation occurs when the geothermal gradient in permafrost drops to less than the geothermal gradients in the underlying thawed soil layers.
Most of studied species managed to survive and propagate in a wide thermal range corresponding to the thermal gradient in the peripheral zones of algal belts.
Experiments on sessile drops evaporating in a normal atmosphere without an applied thermal gradient are reported and compared with an available theoretical model.
The effect of traditional inhibitors of acid corrosion (urotropine, benzotriazole, and thiocarbamide) on the corrosion-electrochemical behavior of an iron plate with a tangential thermal gradient in a sulfate-containing acid solution is examined.
The heat transfer processes occurring in the solid and liquid phases during growth of Bi12GeO20 and Bi4Ge3O12 crystals by the low-thermal gradient Czochralski method are analyzed and compared.
The change of the Josephson supercurrent density js of a weakly connected granular superconductor in response to externally applied arbitrary thermal gradient ?T (nonlinear Seebeck effect) is considered within a model of 3D Josephson junction arrays.
These range from about 410 °C at the top of the Matrei Zone, on the southern margin of the Tauern Window, to about 490 °C at Hochtor in the centre of the Glockner Depression, implying a geothermal gradient of about 25 °C/km during metamorphism.
The Kuzey Detachment might have exhumed rocks a lateral distance of ~53?km at a rapid rate of ~12?mm/year assuming the present ~20° ramp dip, Pliocene monazite crystallization at ~450°C, and a geothermal gradient of ~25°C/km.
Songliao Basin is characterited by a higher geothermal gradient and a higher heat flow.The average geothermal gradient is 42℃/km.The average heat flow is 1.443H FU.In this paper,main characteristics of geothermal field in Songliao Basin have be- en discussed.Relation between geothermal field and oil and gas bearing area have been studied.It is pointed out that higher geothermal gradient is in accord with main source bed in the stratigraphic section and higher geothermal area is approximately co- incide with...
In the metamorphic rock series of Northern Zhongtiao Mountains,the original rocks of Jiangxian Group consist and neritie facies;those of Zhongtiao Group consist of both continental clastic sedimentary rocks of littoral and neritic facies and autogenic composite carbonate rocks of neritc facies.Both groups are all accompanied by volcanic projects. The pelitic metamorphic rocks of Zhongtiao Group vary with metamorphic conditions,and come about a sepence of progressive metamorphic belt ranging from chlorite zo...
This paper focusses on minerals, such as pyroxene, amphibole, plagioclase, seapolite, sphene, magnetite and ilmenite in the early Proterozoic granulite-fa cies rocks of eastern Shandong as well as on their paragenetic features and formation conditions. Metamorphic temperatures and fo_2 were calculated by twopyroxene, amphibole-plagioclase, orthopyroxene-amphibole, clinopyroxene-amphibole and iron-titanium oxide geothermometers. And the pressures were estimated from the compositional characteristics of the i...
地热梯度
geothermal gradient
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