scholarly journals Regional variation in mantle heat flow within the Tanzanian craton

2019 ◽  
Keyword(s):  
Heat Flow ◽  
Regional Variation ◽  
Mantle Heat Flow

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.

scholarly journals Radioactive Heat Production and Terrestrial Heat Flow in the Xiong’an Area, North China

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4608
Author(s):  
Yue Cui ◽  
Chuanqing Zhu ◽  
Nansheng Qiu ◽  
Boning Tang ◽  
Sasa Guo
Keyword(s):  
Heat Flow ◽  
Heat Production ◽  
Central Area ◽  
Geothermal Resources ◽  
Rock Types ◽  
Terrestrial Heat Flow ◽  
Source Mechanisms ◽  
Lower Heat ◽  
Mantle Heat Flow ◽  
Area North

Herein, integrated heat production analysis in the Xiong’an area was conducted by measuring uranium, thorium, and potassium in different rock types to clarify crust heat flow contribution, simulate the conductive terrestrial heat flow, and illustrate heat source mechanisms of Xiong’an area geothermal resources. The study area was divided into three lithosphere structure types from west to east, and heat production corresponded to layer thickness and heat production with the central area having thicker crust and lower heat production than the eastern and western areas. Crustal heat production, mantle heat flow, and crust–mantle heat flow ratio reveal a ‘cold crust-hot mantle’ in the Xiong’an area.

scholarly journals High mantle heat flow in a Precambrian granulite province: Evidence from southern India

2003 ◽  
Vol 108 (B2) ◽  
Author(s):  
Labani Ray ◽  
P. Senthil Kumar ◽  
G. K. Reddy ◽  
Sukanta Roy ◽  
G. V. Rao ◽  
...  
Keyword(s):  
Heat Flow ◽  
Southern India ◽  
Mantle Heat Flow

Paleogeothermal Gradients across an Inverted Hyperextended Rift System (Mauléon Fossil Rift,Western Pyrenees)

2020 ◽  
Author(s):  
Nicolas Saspiturry ◽  
Abdeltif Lahfid ◽  
Thierry Baudin ◽  
Laurent Guillou-Frottier ◽  
Philippe Razin ◽  
...  
Keyword(s):  
Heat Flow ◽  
Thermal Structure ◽  
Ductile Deformation ◽  
Rift System ◽  
Alkaline Magmatism ◽  
Distal Margin ◽  
Geothermal Gradients ◽  
The North ◽  
Mantle Heat Flow ◽  
Paleogeothermal Gradient

<p>Examples of fossil and present-day passive margins resulting from mantle exhumation at the ocean–continent transition appear to have developed under conditions of high mantle heat flow. The pattern of geothermal gradients along these hyperextended margins at the time of rifting is of interest for exploration of geothermal and petroleum resources, but is difficult to access. The fossil rift in the North Pyrenean Zone, which underwent high temperature–low pressure metamorphism and alkaline magmatism during Early Cretaceous hyperextension, was studied to explore the geothermal regime at the time of rifting. Data from a set of 155 samples from densely spaced outcrops and boreholes, analyzed using Raman spectroscopy of carbonaceous material, shed light on the distribution of geothermal gradients across the inverted hyperextended Mauléon rift basin during Albian and Cenomanian time, its period of active extension. The estimated paleogeothermal gradient is strongly related to the structural position along the Albian-Cenomanian rift, increasing along a proximal-distal margin transect from ~34°C/km in the European proximal margin to ~37–47°C/km in the two necking zones and 57–60°C/km in the hyperextended domain. This pattern of the paleogeothermal gradient induced a complex competition between brittle and ductile deformation during crustal extension. A numerical modeling approach reproducing the thermal evolution of the North Pyrenees since 120 Ma suggests that mantle heat flow values may have peaked up to 100 mW.m-2 during the rifting event. We demonstrate that the style of reactivation during subsequent convergence influences the thermal structure of the inverted rift system.</p>

scholarly journals Surface heat flow, crustal temperatures and mantle heat flow in the Proterozoic Trans-Hudson Orogen, Canadian Shield

2002 ◽  
Vol 107 (B12) ◽  
pp. ETG 7-1-ETG 7-19 ◽  
Author(s):  
F. Rolandone ◽  
C. Jaupart ◽  
J. C. Mareschal ◽  
C. Gariépy ◽  
G. Bienfait ◽  
...  
Keyword(s):  
Heat Flow ◽  
Surface Heat ◽  
Canadian Shield ◽  
Surface Heat Flow ◽  
Mantle Heat Flow
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