scholarly journals Reassessing the Thermal Structure of Oceanic Lithosphere With Revised Global Inventories of Basement Depths and Heat Flow Measurements

2018 ◽  
Vol 123 (10) ◽  
pp. 9136-9161 ◽  
Author(s):  
F. D. Richards ◽  
M. J. Hoggard ◽  
L. R. Cowton ◽  
N. J. White
Keyword(s):  
Heat Flow ◽  
Thermal Structure ◽  
Oceanic Lithosphere ◽  
Flow Measurements

Temperature structure of the Andean subduction zone as derived from the 3D geometry of crustal and upper mantle discontinuities

2020 ◽  
Author(s):  
Andres Tassara ◽  
Joaquín Julve ◽  
Iñigo Echeverría ◽  
Ingo Stotz
Keyword(s):  
Heat Flow ◽  
Heat Production ◽  
Thermal Structure ◽  
Surface Heat ◽  
Thermal Parameters ◽  
Continental Lithosphere ◽  
Flow Measurements ◽  
Study Region ◽  
Surface Heat Flow ◽  
Input Model

<p>The distribution of temperature inside active continental margins plays a fundamental role on regulating first order geodynamic processes as the isostatic balance, rheologic behavior of crust and mantle, magmagenesis, volcanism and seismogenesis. In spite of these major implications, well-constrained 3D thermal models are known for few regions of the world (Europe, Western USA, China) where large geophysical databases have been integrated into compositional and structural models of crust and lithospheric mantle from which a thermal model is derived. Here we present a three-dimensional representation of the distribution of temperature underneath the Andean active margin of South America (10°-45°S) that is based on a geophysically-constrained model for the geometry of the subducted slab, continental lithosphere-asthenosphere boundary (LAB), Moho discontinuity and an intracrustal discontinuity (ICD). This input model was constructed by forward modelling the satellite gravity anomaly under the constraint of most of the seismic information published for this region. We use analytical expressions of 1D conductive continental geotherms with adequate boundary conditions that consider the compositional stratification of crust and mantle included in the input model, and the advective thermal effect of slab subduction. The 1D geotherms are assembled into a 3D volume defining the thermal structure of the study region. We test the influence of several thermal parameters and structural configurations of the Andean lithosphere by comparing the resulting surface heat flow distribution of these different models against a database containing heat flow measurements that we compile from the literature. Our results show that the thermal structure and derived surface heat flow is dominantly controlled by the geometry of the thermal boundary layer at the base of the lithosphere, i.e. the slab upper surface below the forearc and LAB inland. Variations on the modeled configuration of the continental lithosphere (i.e. the way on which the geometry of the continental Moho and ICD are considered into the definition of a space-variable thermal conductivity or the length scale for radiogenic heat production) have an effect on surface heat flow that is lower than the average uncertainty of the measurements and therefore can be considered as second-order. The simplicity of our analytical approach allows us to compute hundreds of different models in order to test the sensitivity of results to changes on thermal parameters (conductivity, heat production, mantle potential temperature, etc), which provides a tool for discussing their possible range of values in the context of a subduction margin. We will also show how variations of these models impact on the Moho temperature and therefore in the expected mechanical behavior of crust and mantle in this geotectonic context</p>

Heat flow in a back-arc environment: Intermontane and Omineca Crystalline belts, southern Canadian Cordillera

1984 ◽  
Vol 21 (6) ◽  
pp. 715-726 ◽  
Author(s):  
Earl E. Davis ◽  
Trevor J. Lewis
Keyword(s):  
Steady State ◽  
Heat Flow ◽  
Thermal Structure ◽  
Canadian Cordillera ◽  
Flow Measurements ◽  
Thermal Event ◽  
South Central ◽  
Back Arc ◽  
Glacial Climate ◽  
Reduced Heat Flow

A suite of 20 heat flow measurements has been completed across the Intermontane and Omineca Crystalline belts in south-central British Columbia at about 50°N. Values along the 200 km line are high (83 mW m−2, corrected for Pleistocene glacial climate; reduced heat flow is 67 mW m−2) and uniform (standard deviation = ± 10%). There appears to be no difference in the thermal structure of the two geologic belts. Two sources of heat are considered to explain the level of heat flow observed: a discrete thermal event in the Eocene, and a steady-state supply of heat maintained in the back-arc location by asthenospheric flow caused by nearby subduction. Both can account equally well for the elevated heat flow observed. However, in light of seismic, magnetic, electrical, and flexural data that suggest that the lithosphere may be as thin as 30–40 km, it is concluded that a steady supply of heat must exist since this thickness is much less than the thickness of lithosphere that would be present 50 Ma after even a major thermal event.

The thermal structure of the central Nova Scotia Slope (eastern Canada): seafloor heat flow and thermal maturation models

2017 ◽  
Vol 54 (2) ◽  
pp. 146-162 ◽  
Author(s):  
Eric Negulic ◽  
Keith E. Louden
Keyword(s):  
Heat Flow ◽  
Thermal Structure ◽  
Conductive Heat ◽  
Borehole Data ◽  
Eastern Canada ◽  
Flow Measurements ◽  
Seismic Reflection Data ◽  
Radiogenic Heat ◽  
Reflection Data ◽  
Hydrocarbon Maturation

The thermal history and maturation potential of the central Scotian Slope is constrained using a combination of 47 recently acquired seafloor heat flow measurements, two-dimensional (2D) seismic reflection data, available well data, simple lithospheric rift models, and thermal and petroleum systems modelling. Consistent heat flow values of 41–46 mW·m−2 were measured seaward of the salt diapiric province and across the slope away from the influence of salt structures. Significant but highly variable increases in heat flow were measured for stations overlying salt diapiric structures, reaching values upwards of 72 mW·m−2. Simple models of conductive heat transfer with static salt geometries constrained from reflection profiles indicate that two of the four models fit the data, whereas two indicate much higher values suggestive of additional, convective effects. Dynamic 2D thermal models were developed to incorporate the effects of lithospheric rifting, crustal stretching, and radiogenic heat production in the sediment and basement. These models help constrain the hydrocarbon maturation potential of the central Scotian Slope, where deep borehole data are lacking. Our results suggest that a potential Late Jurassic source rock interval rests primarily within the late oil window and that salt structures act primarily to reduce maturation in the adjacent deep sediment layers.

Heat flow measurements in Yellowstone Lake and the thermal structure of the Yellowstone Caldera

1977 ◽  
Vol 82 (26) ◽  
pp. 3719-3732 ◽  
Author(s):  
Paul Morgan ◽  
David D. Blackwell ◽  
Robert E. Spafford ◽  
Robert B. Smith
Keyword(s):  
Heat Flow ◽  
Thermal Structure ◽  
Flow Measurements ◽  
Yellowstone Lake ◽  
Yellowstone Caldera

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

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

scholarly journals Heat Flow, Geotherms, Density and Lithosphere Thickness in SW of Iberia (South of Portugal)

2018 ◽  
Vol 1 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Maria Rosa Alves Duque
Keyword(s):  
Heat Flow ◽  
Thermal Structure ◽  
Average Density ◽  
Ore Deposits ◽  
Flow Density ◽  
The South ◽  
Lithosphere Thickness ◽  
Structure Density ◽  
Using Data ◽  
Lateral Variations

Thermal structure, density distribution and lithosphere thickness in the SW part of the Iberian Peninsula are studied using data obtained in the South Portuguese Zone (SPZ) and SW border of the Ossa Morena Zone (OMZ) in the South of Portugal. Five different regions were defined, and models were built for each region. Geotherms were obtained using average density values from data published. The high values of heat flow density in these regions are attributed to occurrence of anomalous heat sources due to radioactivity content and exothermic chemical reactions associated to ore deposits in the zone. The results obtained with models based on isostasy in the region led to lithosphere thickness values between 95 and 96 km in the SPZ and a lower value of 94.5 km in the SW border of the OMZ. Analysis of geotherms shows lateral variations of temperature at the same depth. These lateral variations are compared with information obtained with seismic data.

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