scholarly journals Heat Flow in the Cretaceous of Northwestern Kansas and Implications for Regional Hydrology

1997 ◽  
pp. 1-11
Author(s):  
Andrea Forster ◽  
Daniel F. Merriam
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Thermal Structure ◽  
Flow Density ◽  
Thermal Gradients ◽  
Conductive Heat ◽  
Flow Estimation ◽  
Average Value ◽  
Dakota Formation ◽  
Porosity And Permeability

Temperature logs are interpreted to investigate the thermal structure of the units overlying the Kansas portion of the Cretaceous Dakota aquifer. The aim of this study is to determine if additional heat input by fluids exists and thus clarify whether the overall conductive heat flow from the basement through the sequence might be overprinted by heat advection. Although interval thermal gradients are determined for different lithologic (stratigraphic) units, the shale thermal gradients are preferred for heat-flow estimation. Shale thermal conductivity as measured in Mesozoic shales in Nebraska and South Dakota is extrapolated to the area because of the similar lithology. A few thermal-conductivity values are determined in sandstone samples of the Dakota Formation and also used in heat-flow estimation. In general, the noncalcareous, marine Cretaceous shales (Pierre, Carlile, Graneros, and Kiowa) show different thermal gradients. Gradients in the Pierre (average value 58.5°C/km) and Carlile (55.5°C/km) are slightly higher than the average gradient in the Graneros Shale (45.1°C/km) and Kiowa Formation (46.5°C/km). The higher thermal gradients are limited to the extreme northwestern corner of the study area where the Pierre and Carlile are present. The heat-flow density of 69-74 mW/m2 observed there is slightly higher than the average of 60 mW/m2 typical for central and eastern Kansas. The higher heat flow observed is in the range of data reported and mapped for northeastern Colorado and the Nebraska Panhandle on the western flank of the Chadron Arch, an area with geothermal overprint by warm fluids. Regional differences in heat flow in western Kansas seemingly are caused by the different composition, porosity, and permeability of the aquifer and the nearness to recharge areas.

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 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.

Inversion of bottom‐hole temperature data: The Pineview field, Utah‐Wyoming thrust belt

Geophysics ◽  
1988 ◽  
Vol 53 (5) ◽  
pp. 707-720 ◽  
Author(s):  
Dave Deming ◽  
David S. Chapman
Keyword(s):  
Thermal Conductivity ◽  
Temperature Field ◽  
Heat Flow ◽  
Random Noise ◽  
Synthetic Data ◽  
Element Model ◽  
Geothermal Gradient ◽  
Oil Field ◽  
Conductive Heat ◽  
Bottom Hole

The present day temperature field in a sedimentary basin is a constraint on the maturation of hydro‐carbons; this temperature field may be estimated by inverting corrected bottom‐hole temperature (BHT) data. Thirty‐two BHTs from the Pineview oil field are corrected for drilling disturbances by a Horner plot and inverted for the geothermal gradient in nine formations. Both least‐squares [Formula: see text] norm and uniform [Formula: see text] norm inversions are used; the [Formula: see text] norm is found to be more robust for the Pineview data. The inversion removes random error from the corrected BHT data by partitioning scatter between noise associated with the BHT measurement and correction processes and local variations in the geothermal gradient. Three‐hundred thermal‐conductivity and density measurements on drill cuttings are used, together with formation density logs, to estimate the in situ thermal conductivity of six of the nine formations. The thermal‐conductivity estimates are used in a finite‐element model to evaluate 2-D conductive heat refraction and, for a series of inversions of synthetic data, to assess the influence of systematic and random noise on the inversion results. A temperature‐anomaly map illustrates that a temperature field calculated by a forward application of the inversion results has less error than any single corrected BHT. Mean background heat flow at Pineview is found to be [Formula: see text] (±13 percent), but is locally higher [Formula: see text] due to heat refraction. The BHT inversion (1) is limited by systematic noise or model error, (2) achieves excellent resolution of a temperature field although resolution of individual formation gradients may be poor, and (3) generally cannot detect lateral variations in heat flow unless thermal‐conductivity structure is constrained.

scholarly journals Heat flow density estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Pauline Harlé ◽  
Alexandra R. L. Kushnir ◽  
Coralie Aichholzer ◽  
Michael J. Heap ◽  
Régis Hehn ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Ambient Temperature ◽  
Sedimentary Rocks ◽  
Flow Density ◽  
Upper Rhine Graben ◽  
Heat Flow Density ◽  
Density Estimates ◽  
Wet Rocks ◽  
Upper Rhine

AbstractThe Upper Rhine Graben (URG) has been extensively studied for geothermal exploitation over the past decades. Yet, the thermal conductivity of the sedimentary cover is still poorly constrained, limiting our ability to provide robust heat flow density estimates. To improve our understanding of heat flow density in the URG, we present a new large thermal conductivity database for sedimentary rocks collected at outcrops in the area including measurements on (1) dry rocks at ambient temperature (dry); (2) dry rocks at high temperature (hot) and (3) water-saturated rocks at ambient temperature (wet). These measurements, covering the various lithologies composing the sedimentary sequence, are associated with equilibrium-temperature profiles measured in the Soultz-sous-Forêts wells and in the GRT-1 borehole (Rittershoffen) (all in France). Heat flow density values considering the various experimental thermal conductivity conditions were obtained for different depth intervals in the wells along with average values for the whole boreholes. The results agree with the previous heat flow density estimates based on dry rocks but more importantly highlight that accounting for the effect of temperature and water saturation of the formations is crucial to providing accurate heat flow density estimates in a sedimentary basin. For Soultz-sous-Forêts, we calculate average conductive heat flow density to be 127 mW/m2 when considering hot rocks and 184 mW/m2 for wet rocks. Heat flow density in the GRT-1 well is estimated at 109 and 164 mW/m2 for hot and wet rocks, respectively. Results from the Rittershoffen well suggest that heat flow density is nearly constant with depth, contrary to the observations for the Soultz-sous-Forêts site. Our results show a positive heat flow density anomaly in the Jurassic formations, which could be explained by a combined effect of a higher radiogenic heat production in the Jurassic sediments and thermal disturbance caused by the presence of the major faults close to the Soultz-sous-Forêts geothermal site. Although additional data are required to improve these estimates and our understanding of the thermal processes, we consider the heat flow densities estimated herein as the most reliable currently available for the URG.

Measurement of the thermal conductivity of thin layers using a scanning thermal microscope

2001 ◽  
Vol 16 (9) ◽  
pp. 2530-2543 ◽  
Author(s):  
Erwin R. Meinders
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Thermal Structure ◽  
Thin Layers ◽  
Heat Diffusion ◽  
Sputter Deposited ◽  
Relative Differences ◽  
Conductivity Of Thin Films ◽  
Change Material

A scanning thermal microscope (SThM) was used to measure the thermal conductivity of thin sputter-deposited films in the thickness range of 10 nm–10 μm. The SThM method is based on a heated tip that is scanned across the surface of a sample. The heat flowing into the sample is correlated to the local thermal conductivity of the sample. Issues like the contact force, the surface roughness of the sample, and tip degradation, which determine to a great extent the contact area between tip and surface, and thus the heat flow to the sample, are addressed in the paper. A calibration curve was measured from known reference materials to quantify the sample heat flow. This calibration was used to determine the effective thermal conductivity of samples. Further, the heat diffusion through a layered sample due to a surface heat source was analyzed with an analytical and numerical model. Measurements were performed with films of aluminum, ZnS–SiO2, and GeSbTe phase change material of variable thickness and sputter-deposited on substrates of glass, silicon, or polycarbonate. It is shown in the paper that the SThM is a suitable tool to visualize relative differences in thermal structure of nanometer resolution. Determination of the thermal conductivity of thin layers is possible for layers in the micrometer range. It is concluded that the SThM is not sensitive enough to measure accurately the thermal conductivity of thin films in the nanometer range. Suggestions for improvement of the SThM method are given.

scholarly journals Shear heating reconciles thermal models with the metamorphic rock record of subduction

2018 ◽  
Vol 115 (46) ◽  
pp. 11706-11711 ◽  
Author(s):  
Matthew J. Kohn ◽  
Adrian E. Castro ◽  
Buchanan C. Kerswell ◽  
César R. Ranero ◽  
Frank S. Spear
Keyword(s):  
Heat Flow ◽  
Subduction Zones ◽  
Thermal Structure ◽  
Metamorphic Rocks ◽  
Shear Stresses ◽  
Thermal Models ◽  
Average Value ◽  
Temperature Conditions ◽  
Mechanical Models ◽  
Shear Heating

Some commonly referenced thermal-mechanical models of current subduction zones imply temperatures that are 100–500 °C colder at 30–80-km depth than pressure–temperature conditions determined thermobarometrically from exhumed metamorphic rocks. Accurately inferring subduction zone thermal structure, whether from models or rocks, is crucial for predicting metamorphic reactions and associated fluid release, subarc melting conditions, rheologies, and fault-slip phenomena. Here, we compile surface heat flow data from subduction zones worldwide and show that values are higher than can be explained for a frictionless subduction interface often assumed for modeling. An additional heat source––likely shear heating––is required to explain these forearc heat flow values. A friction coefficient of at least 0.03 and possibly as high as 0.1 in some cases explains these data, and we recommend a provisional average value of 0.05 ± 0.015 for modeling. Even small coefficients of friction can contribute several hundred degrees of heating at depths of 30–80 km. Adding such shear stresses to thermal models quantitatively reproduces the pressure–temperature conditions recorded by exhumed metamorphic rocks. Comparatively higher temperatures generally drive rock dehydration and densification, so, at a given depth, hotter rocks are denser than colder rocks, and harder to exhume through buoyancy mechanisms. Consequently––conversely to previous proposals––exhumed metamorphic rocks might overrepresent old-cold subduction where rocks at the slab interface are wetter and more buoyant than in young-hot subduction zones.

Heat production and thermal conductivity of rocks from the Pikwitonei–Sachigo continental cross section, central Manitoba: implications for the thermal structure of Archean crust

1987 ◽  
Vol 24 (8) ◽  
pp. 1583-1594 ◽  
Author(s):  
David M. Fountain ◽  
Matthew H. Salisbury ◽  
Kevin P. Furlong
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Cross Section ◽  
Heat Production ◽  
Thermal Structure ◽  
Granulite Facies ◽  
Surface Heat ◽  
Gamma Ray Spectrometry ◽  
Surface Heat Flow ◽  
Greenstone Belts

The Pikwitonei and Sachigo subprovinces of central Manitoba provide a cross-sectional view of the Superior Province crust. In cross section, the upper to mid-level crust is composed of synformal greenstone belts surrounded by tonalitic gneisses, both of which are intruded by granitoid plutons. This crustal structure persists downward into the granulite facies, where keels of the greenstone belts can be found. To constrain thermal models of the crust, we measured heat production and thermal conductivity in 60 rocks from this terrain using standard gamma-ray spectrometry and divided bar techniques. Large vertical and lateral heterogeneities in heat production in the upper crust are evident; heat production is high in granites and metasedimentary rocks, intermediate in tonalite gneisses, and low in the portions of greenstone belts dominated by mafic meta-igneous rocks. In the deeper granulite facies rocks, heat production decreases by a factor of two in the tonalitic gneisses and remains low in the high-grade mafic rocks. When applied to the Pikwitonei–Sachigo crust cross section, the laboratory data here do not support step function or exponential models of the variation of heat production with depth. However, estimates of surface heat flow and surface heat production for various sites in the crustal model yield the well-known linear relationship between surface heat production and surface heat flow observed for heat-flow provinces for both one- and two-dimensional models. This demonstrates that determinations of heat production with depth based on inversion of the linear heat-production–heat-flow relationship are nonunique.

scholarly journals Estimating late-winter heat flow to the atmosphere from the lake-dominated Alaskan North Slope

1999 ◽  
Vol 45 (150) ◽  
pp. 315-324 ◽  
Author(s):  
Martin O. Jeffries ◽  
Tingjun Zhang ◽  
Karoline Frey ◽  
Nick Kozlenko
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
North Slope ◽  
Late Winter ◽  
Conductive Heat ◽  
Soil System ◽  
Radar Images ◽  
The North ◽  
North Slope Of Alaska ◽  
Alaskan North Slope

AbstractThe conductive heat flux through the snow cover (Fa) is used as a proxy to examine the hypothesis that there is a significant heat flow from the Alaskan North Slope to the atmosphere because of the large number of lakes in the region.Fais estimated from measurements of snow depth, temperature and density on tundra, grounded ice and floating ice in mid-April 1997 at six lakes near Barrow, northwestern Alaska. The meanFavalues from tundra, grounded ice and floating ice are 1.5, 5.4 and 18.6 W m2, respectively. A numerical model of the coupled snow/ice/water/soil system is used to simulateFaand there is good agreement between the simulated and measured fluxes. The flux from the tundra is low because the soils have a relatively low thermal conductivity and the active layer cools significantly after freezing completely the previous autumn. The flux from the floating ice is high because the ice has a relatively high thermal conductivity, and a body of relatively warm water remains below the growing ice at the end of winter. The flux from the grounded ice is intermediate between that from the tundra and that from the floating ice, and depends on the timing of the contact between the growing ice and the lake sediments, and whether or not those sediments freeze completely. Using the estimatedFavalues combined with the areal fractions of tundra, grounded ice and floating ice derived from synthetic aperture radar images, area-weightedFavalues are calculated for six areas.Favalues for the ice vary between 9.8 and 13.8 W m−2, and those from the ice plus tundra vary between 3.9 and 5.3 W m−2. TheFavalues are similar to those observed in the sea-ice-covered regions of the south and north polar oceans in winter. The North Slope of Alaska may thus make a significant contribution to the regional energy budget in winter.

scholarly journals Estimating late-winter heat flow to the atmosphere from the lake-dominated Alaskan North Slope

1999 ◽  
Vol 45 (150) ◽  
pp. 315-324 ◽  
Author(s):  
Martin O. Jeffries ◽  
Tingjun Zhang ◽  
Karoline Frey ◽  
Nick Kozlenko
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
North Slope ◽  
Late Winter ◽  
Conductive Heat ◽  
Soil System ◽  
Radar Images ◽  
The North ◽  
North Slope Of Alaska ◽  
Alaskan North Slope

AbstractThe conductive heat flux through the snow cover (Fa) is used as a proxy to examine the hypothesis that there is a significant heat flow from the Alaskan North Slope to the atmosphere because of the large number of lakes in the region. Fa is estimated from measurements of snow depth, temperature and density on tundra, grounded ice and floating ice in mid-April 1997 at six lakes near Barrow, northwestern Alaska. The mean Fa values from tundra, grounded ice and floating ice are 1.5, 5.4 and 18.6 W m2, respectively. A numerical model of the coupled snow/ice/water/soil system is used to simulate Fa and there is good agreement between the simulated and measured fluxes. The flux from the tundra is low because the soils have a relatively low thermal conductivity and the active layer cools significantly after freezing completely the previous autumn. The flux from the floating ice is high because the ice has a relatively high thermal conductivity, and a body of relatively warm water remains below the growing ice at the end of winter. The flux from the grounded ice is intermediate between that from the tundra and that from the floating ice, and depends on the timing of the contact between the growing ice and the lake sediments, and whether or not those sediments freeze completely. Using the estimated Fa values combined with the areal fractions of tundra, grounded ice and floating ice derived from synthetic aperture radar images, area-weighted Fa values are calculated for six areas. Fa values for the ice vary between 9.8 and 13.8 W m−2, and those from the ice plus tundra vary between 3.9 and 5.3 W m−2. The Fa values are similar to those observed in the sea-ice-covered regions of the south and north polar oceans in winter. The North Slope of Alaska may thus make a significant contribution to the regional energy budget in winter.

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