scholarly journals Geothermal Regime and Deep Temperatures of the Siberian Platform

2018 ◽  
Vol 1 (1) ◽  
pp. 35-40
Author(s):  
Raisa Dorofeeva
Keyword(s):  
Heat Flow ◽  
Siberian Platform ◽  
Lower Cambrian ◽  
Seepage Flow ◽  
Salt Dome ◽  
Flow Measurements ◽  
Basement Rocks ◽  
Metamorphic Basement ◽  
Borehole Temperatures ◽  
Geothermal Regime

The geothermal regime of the southern segment of the East Siberian platform, where more than 200 heat-flow measurements have been carried out, is well-understood. The present work deals with the study of deep temperatures of the southern Siberian platform, based on results of geothermal measurements in more than 70 boreholes. In addition, measurements of thermal properties have been made mostly on core samples representing the Vendian terrigenous deposits and Riphean magmatic and metamorphic basement rocks. The basement rocks may be subdivided into two groups, with thermal conductivity coefficients varying in the range of 2 and 3 W/m/K. Higher coefficients indicate the presence of carbonate-halogen admixtures. Studies have also been made of the borehole thermograms and temperatures at the bottom and top of the Moti suite, of lower Cambrian age. These boreholes vary in depth from 1300 to 6000 m, and the borehole temperatures attain values as high as 70оC. In this region average heat flow is 38±4 mW/m2. Higher heat flow values (45±6 mW/m2) are observed in the anticlinal domes and salt-dome crests, while low heat flow seems to be typical of marginal uplifts. This peculiar geothermal condition is also closely related to hydrodynamic features of the area, where underground seepage flow penetrates to depths of 3-5 km while conductive diffusion of heat prevails in the deeper crust. It is argued that such anomalous conditions exert influence on the dynamics of hydrocarbon accumulation, which in turn is also predetermined by geothermal conditions.

Systematic heat flow measurements across the Wagner Basin, northern Gulf of California

2017 ◽  
Vol 479 ◽  
pp. 340-353 ◽  
Author(s):  
Florian Neumann ◽  
Raquel Negrete-Aranda ◽  
Robert N. Harris ◽  
Juan Contreras ◽  
John G. Sclater ◽  
...  
Keyword(s):  
Heat Flow ◽  
Gulf Of California ◽  
Flow Measurements

scholarly journals The first deep heat flow determination in crystalline basement rocks beneath the Western Canadian Sedimentary Basin

2014 ◽  
Vol 197 (2) ◽  
pp. 731-747 ◽  
Author(s):  
Jacek Majorowicz ◽  
Judith Chan ◽  
James Crowell ◽  
Will Gosnold ◽  
Larry M. Heaman ◽  
...  
Keyword(s):  
Heat Flow ◽  
Sedimentary Basin ◽  
Crystalline Basement ◽  
Basement Rocks

Thermal regime of the lithosphere in the Canadian ShieldThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe — parameters, processes, and the evolution of a continent.

2010 ◽  
Vol 47 (4) ◽  
pp. 389-408 ◽  
Author(s):  
Claire Perry ◽  
Carmen Rosieanu ◽  
Jean-Claude Mareschal ◽  
Claude Jaupart
Keyword(s):  
Heat Flow ◽  
Heat Generation ◽  
Seismic Refraction ◽  
Surface Heat ◽  
Canadian Shield ◽  
P Wave ◽  
Seismic Velocities ◽  
Flow Measurements ◽  
Surface Heat Flow ◽  
Mantle Heat Flow

Geothermal studies were conducted within the framework of Lithoprobe to systematically document variations of heat flow and surface heat production in the major geological provinces of the Canadian Shield. One of the main conclusions is that in the Shield the variations in surface heat flow are dominated by the crustal heat generation. Horizontal variations in mantle heat flow are too small to be resolved by heat flow measurements. Different methods constrain the mantle heat flow to be in the range of 12–18 mW·m–2. Most of the heat flow anomalies (high and low) are due to variations in crustal composition and structure. The vertical distribution of radioelements is characterized by a differentiation index (DI) that measures the ratio of the surface to the average crustal heat generation in a province. Determination of mantle temperatures requires the knowledge of both the surface heat flow and DI. Mantle temperatures increase with an increase in surface heat flow but decrease with an increase in DI. Stabilization of the crust is achieved by crustal differentiation that results in decreasing temperatures in the lower crust. Present mantle temperatures inferred from xenolith studies and variations in mantle seismic P-wave velocity (Pn) from seismic refraction surveys are consistent with geotherms calculated from heat flow. These results emphasize that deep lithospheric temperatures do not always increase with an increase in the surface heat flow. The dense data coverage that has been achieved in the Canadian Shield allows some discrimination between temperature and composition effects on seismic velocities in the lithospheric mantle.

scholarly journals Present-day geothermal regime of the Uliastai Depression, Erlian Basin, North China

2018 ◽  
Vol 37 (2) ◽  
pp. 770-786 ◽  
Author(s):  
Wei Xu ◽  
Shaopeng Huang ◽  
Jiong Zhang ◽  
Ruyang Yu ◽  
Yinhui Zuo ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Thermal Structure ◽  
Rheological Characteristic ◽  
Rheological Parameter ◽  
Lithospheric Thickness ◽  
Terrestrial Heat Flow ◽  
Geothermal Regime ◽  
Mantle Heat Flow ◽  
Erlian Basin

In this study, we calculated the present-day terrestrial heat flow of the Uliastai Depression in Erlian Basin by using systematical steady-state temperature data obtained from four deep boreholes and 89 thermal conductivity measurements from 22 boreholes. Then, we calculated the lithospheric thermal structure, thermal lithospheric thickness, and lithospheric thermo-rheological structure by combining crustal structure, thermal conductivity, heat production, and rheological parameter data. Research from the Depression shows that the present-day terrestrial heat flow ( qs) is 86.3 ± 2.3 mW/m2, higher than the average of 60.4 ± 12.3 mW/m2 of the continental area of China. Mantle heat flow ( qm) in the Depression ranges from 33.7 to 39.3 mW/m2, qm/ qs ranges from 40 to 44%, show that the crust plays the dominant position in the terrestrial heat flow. The thermal thickness of the lithosphere is about 74–88 km and characterized by a “strong crust–weak mantle” rheological characteristic. The total lithospheric strength is 1.5 × 1012 N/m under wet mantle conditions. Present-day geothermal regime indicates that the Uliastai Depression has a high thermal background, the activity of the deep-seated lithosphere is relatively intense. This result differs significantly from the earlier understanding that the area belongs to a cold basin. However, a hot basin should be better consistent with the evidences from lithochemistry and geophysical observations. The results also show the melts/fluids in the study area may be related to the subduction of the Paleo-Asian Ocean. The study of the geothermal regime in the Uliastai Depression provides new geothermal evidence for the volcanic activity in the eastern part of the Central Asian Orogenic Belt and has significant implications for the geodynamic characteristics.

New terrestrial heat flow measurements on the Nazca Plate

1976 ◽  
Vol 29 (2) ◽  
pp. 243-254 ◽  
Author(s):  
Roger N. Anderson ◽  
Marcus G. Langseth ◽  
Victor Vacquier ◽  
Jean Francheteau
Keyword(s):  
Heat Flow ◽  
Flow Measurements ◽  
Nazca Plate ◽  
Terrestrial Heat Flow

Some new measurements of heat flow in the Superior Province of the Canadian Shield

1987 ◽  
Vol 24 (7) ◽  
pp. 1486-1489 ◽  
Author(s):  
Malcolm Drury ◽  
Alan Taylor
Keyword(s):  
Standard Deviation ◽  
Heat Flow ◽  
Canadian Shield ◽  
Superior Province ◽  
Flow Measurements ◽  
Radiogenic Heat ◽  
Radiogenic Heat Production ◽  
Climatic Variations ◽  
The Mean ◽  
A Site

Borehole heat-flow measurements are reported from six new sites in the Superior Province of the Canadian Shield. Values adjusted for glaciation effects, but not for Holocene climatic variations, range from 42 to 56 mW/m2. When these new values are combined with 21 previously published borehole values the mean is 42 mW/m2 with a standard deviation of 11 mW/m2. The data for a site on the Lac du Bonnet batholith suggest that the batholith has a thin veneer, less than 3 km, of rock of high radiogenic heat production at the surface.

Heat flow measurements in the southern portion of the Gulf of California

1973 ◽  
Vol 19 (2) ◽  
pp. 198-208 ◽  
Author(s):  
Lawrence A. Lawver ◽  
John G. Sclater ◽  
Thomas L. Henyey ◽  
J. Rogers
Keyword(s):  
Heat Flow ◽  
Gulf Of California ◽  
Flow Measurements

Geological environment of the Cigar Lake uranium deposit

1993 ◽  
Vol 30 (4) ◽  
pp. 653-673 ◽  
Author(s):  
P. Bruneton
Keyword(s):  
Uranium Deposit ◽  
Transitional Zone ◽  
Uranium Deposits ◽  
Athabasca Basin ◽  
Structural Framework ◽  
Basement Rocks ◽  
Metamorphic Basement ◽  
Basement Ridge ◽  
Archean Basement ◽  
East West

The Cigar Lake uranium deposit occurs within the Athabasca Basin of northern Saskatchewan, Canada. Like other major uranium deposits of the basin, it is located at the unconformity separating Helikian sandstones of the Athabasca Group from Aphebian metasediments and plutonic rocks of the Wollaston Group. The Athabasca Group was deposited in an intra-continental sedimentary basin that was filled by fluviatile terrestrial quartz sandstones and conglomerates. The group appears undeformed and its actual maximum thickness is about 1500 m. On the eastern side of the basin, the detrital units correspond to the Manitou Falls Formations where most of the uranium deposits are located. The Lower Pelitic unit of the Wollaston Group, which lies directly on the Archean basement, is considered to be the most favourable horizon for uranium mineralization. During the Hudsonian orogeny (1800–1900 Ma), the group underwent polyphase deformation and upper amphibolite facies metamorphism. The Hudsonian orogeny was followed by a long period of erosion and weathering and the development of a paleoweathering profile.On the Waterbury Lake property, the Manitou Falls Formation is 250–500 m thick and corresponds to units MFd, MFc, and MFb. The conglomeratic MFb unit hosts the Cigar Lake deposit. However, the basal conglomerate is absent at the deposit, wedging out against an east–west, 20 m high, pre-Athabasca basement ridge, on top of which is located the orebody.Two major lithostructural domains are present in the metamorphic basement of the property: (1) a southern area composed mainly of pelitic metasediments (Wollaston Domain) and (2) a northern area with large lensoid granitic domes (Mudjatik Domain). The Cigar Lake east–west pelitic basin, which contains the deposit, is located in the transitional zone between the two domains. The metamorphic basement rocks in the basin consist mainly of graphitic metapelitic gneisses and calcsilicate gneisses, which are inferred to be part of the Lower Pelitic unit. Graphite- and pyrite-rich "augen gneisses," an unusual facies within the graphitic metapelitic gneisses, occur primarily below the Cigar Lake orebody.The mineralogy and geochemistry of the graphitic metapelitic gneisses suggest that they were originally shales. The abundance of magnesium in the intercalated carbonates layers indicates an evaporitic origin.The structural framework is dominated by large northeast–southwest lineaments and wide east–west mylonitic corridors. These mylonites, which contain the augen gneisses, are considered to be the most favourable features for the concentration of uranium mineralization.Despite the presence of the orebody, large areas of the Waterbury Lake property remain totally unexplored and open for new discoveries.

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