Geothermal regime in the Qaidam basin, northeast Qinghai–Tibet Plateau

2003 ◽  
Vol 140 (6) ◽  
pp. 707-719 ◽  
Author(s):  
QIU NANSHENG

The thermal properties of rocks in the upper crust of the Qaidam basin are given based on measurements of 98 thermal conductivities and 50 heat production values. Nineteen new measured heat flow data were obtained from thermal conductivity data and systematic steady-state temperature data. This paper contributes 28 calculated heat flow values for the basin for the first time. Examination of 47 heat flow values, ranging from 31.3 to 70.4 mW/m2 with an average value of 52.6±9.6 mW/m2, gives the heat flow distribution character of the basin: high heat flows over 60 mW/m2 are distributed in the western and central parts of the basin. Lower heat flow values are found in the eastern part and north marginal area of the basin, with values less 40 mW/m2. The Qaidam basin heatflow data show a linear relationship between heatflow and heat production, based on thermal structure analysis. The thermal structure of the lithosphere is characterized as having a ‘hot crust’ but ‘cold mantle’. Heat production in the upper crust is a significant source of heat in the basin and contributes up to 56.8% of the surface heat flow. The heat flow province is of great geophysical significance, and the thermal structure of the area gives clues about the regional geodynamics. Study of the Qaidam basin thermal structure shows that the crust has been highly active, particularly during its most recent geological evolution. This corresponds to Himalayan tectonic movements during latest Eocene to Quaternary times in the region of the Qinghai–Tibet Plateau. Since the Qaidam basin is in the northeastern area of the Qinghai–Tibet Plateau, the heat flow values and the thermal structure of the basin may give some insight into the thermal state of the plateau, and study of thermal regime of the Qaidam basin could in turn provide useful information about the tectonics of the Qinghai–Tibet Plateau.

2011 ◽  
Vol 12 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
Hideki Hamamoto ◽  
Makoto Yamano ◽  
Shusaku Goto ◽  
Masataka Kinoshita ◽  
Keiko Fujino ◽  
...  

2019 ◽  
Vol 219 (3) ◽  
pp. 1648-1659 ◽  
Author(s):  
B Mather ◽  
L Moresi ◽  
P Rayner

SUMMARY The variation of temperature in the crust is difficult to quantify due to the sparsity of surface heat flow observations and lack of measurements on the thermal properties of rocks at depth. We examine the degree to which the thermal structure of the crust can be constrained from the Curie depth and surface heat flow data in Southeastern Australia. We cast the inverse problem of heat conduction within a Bayesian framework and derive its adjoint so that we can efficiently find the optimal model that best reproduces the data and prior information on the thermal properties of the crust. Efficiency gains obtained from the adjoint method facilitate a detailed exploration of thermal structure in SE Australia, where we predict high temperatures within Precambrian rocks of 650 °C due to relatively high rates of heat production (0.9–1.4 μW m−3). In contrast, temperatures within dominantly Phanerozoic crust reach only 520 °C at the Moho due to the low rates of heat production in Cambrian mafic volcanics. A combination of the Curie depth and heat flow data is required to constrain the uncertainty of lower crustal temperatures to ±73 °C. We also show that parts of the crust are unconstrained if either data set is omitted from the inversion.


2017 ◽  
Vol 430 ◽  
pp. 12-20 ◽  
Author(s):  
QiuFang Chang ◽  
ZhongPing Lai ◽  
FuYuan An ◽  
HaiLei Wang ◽  
YanBin Lei ◽  
...  

2018 ◽  
Vol 12 (2) ◽  
pp. 491-504 ◽  
Author(s):  
John W. Goodge

Abstract. Terrestrial heat flow is a critical first-order factor governing the thermal condition and, therefore, mechanical stability of Antarctic ice sheets, yet heat flow across Antarctica is poorly known. Previous estimates of terrestrial heat flow in East Antarctica come from inversion of seismic and magnetic geophysical data, by modeling temperature profiles in ice boreholes, and by calculation from heat production values reported for exposed bedrock. Although accurate estimates of surface heat flow are important as an input parameter for ice-sheet growth and stability models, there are no direct measurements of terrestrial heat flow in East Antarctica coupled to either subglacial sediment or bedrock. As has been done with bedrock exposed along coastal margins and in rare inland outcrops, valuable estimates of heat flow in central East Antarctica can be extrapolated from heat production determined by the geochemical composition of glacial rock clasts eroded from the continental interior. In this study, U, Th, and K concentrations in a suite of Proterozoic (1.2–2.0 Ga) granitoids sourced within the Byrd and Nimrod glacial drainages of central East Antarctica indicate average upper crustal heat production (Ho) of about 2.6  ±  1.9 µW m−3. Assuming typical mantle and lower crustal heat flux for stable continental shields, and a length scale for the distribution of heat production in the upper crust, the heat production values determined for individual samples yield estimates of surface heat flow (qo) ranging from 33 to 84 mW m−2 and an average of 48.0  ±  13.6 mW m−2. Estimates of heat production obtained for this suite of glacially sourced granitoids therefore indicate that the interior of the East Antarctic ice sheet is underlain in part by Proterozoic continental lithosphere with an average surface heat flow, providing constraints on both geodynamic history and ice-sheet stability. The ages and geothermal characteristics of the granites indicate that crust in central East Antarctica resembles that in the Proterozoic Arunta and Tennant Creek inliers of Australia but is dissimilar to other areas like the Central Australian Heat Flow Province that are characterized by anomalously high heat flow. Age variation within the sample suite indicates that central East Antarctic lithosphere is heterogeneous, yet the average heat production and heat flow of four age subgroups cluster around the group mean, indicating minor variation in the thermal contribution to the overlying ice sheet from upper crustal heat production. Despite these minor differences, ice-sheet models may favor a geologically realistic input of crustal heat flow represented by the distribution of ages and geothermal characteristics found in these glacial clasts.


2017 ◽  
Author(s):  
John W. Goodge

Abstract. Terrestrial heat flow is a critical first-order factor governing the thermal condition and, therefore, mechanical stability of Antarctic ice sheets, yet heat flow across Antarctica is poorly known. Previous estimates of terrestrial heat flow come from inversion of seismic and magnetic geophysical data, by modeling temperature profiles in ice boreholes, and by calculation from heat production values reported for exposed bedrock. Although accurate estimates of surface heat flow are important as an input parameter for ice-sheet growth and stability models, there are no direct measurements of terrestrial heat flow in East Antarctica coupled to either subglacial sediment or bedrock. Bedrock outcrop is limited to coastal margins and rare inland exposures, yet valuable estimates of heat flow in central East Antarctica can be extrapolated from heat production determined by the geochemical composition of glacial rock clasts eroded from the continental interior. In this study, U, Th and K concentrations in a suite of Proterozoic (1.2–2.0 Ga) granitoids sourced within the Byrd and Nimrod glacial drainages of central East Antarctica indicate average upper crustal heat production (Ho) of about 2.6 ± 1.9 μW m-3. Assuming typical mantle and lower crustal heat flux for stable continental shields, and a length scale for the distribution of heat production in the upper crust, the heat production values determined for individual samples yield estimates of surface heat flow (qo) ranging from 33–84 mW m-2 and an average of 48.0 ± 13.6 mW m-2. Estimates of heat production obtained for this suite of glacially-sourced granitoids therefore indicate that the interior of the East Antarctic ice sheet is underlain in part by Proterozoic continental lithosphere with average surface heat flow, providing constraints on both geodynamic history and ice-sheet stability. The ages and geothermal characteristics of the granites indicate that crust in central East Antarctica resembles that in the Proterozoic Arunta and Tenant Creek inliers of Australia, but is dissimilar to other areas characterized by anomalously high heat flow in the Central Australian Heat Flow Province. Age variation within the sample suite indicates that central East Antarctic lithosphere is heterogeneous, yet the average heat production and heat flow of four age subgroups cluster around the group mean, indicating minor variation in thermal contribution to the overlying ice sheet from upper crustal heat production. Despite their minor differences, ice-sheet models may favor a geologically realistic model of crustal heat flow represented by such a distribution of ages and geothermal characteristics.


2016 ◽  
Vol 10 (4) ◽  
pp. 1591-1603 ◽  
Author(s):  
Xicai Pan ◽  
Yanping Li ◽  
Qihao Yu ◽  
Xiaogang Shi ◽  
Daqing Yang ◽  
...  

Abstract. Seasonally variable thermal conductivity in active layers is one important factor that controls the thermal state of permafrost. The common assumption is that this conductivity is considerably lower in the thawed than in the frozen state, λt/λf < 1. Using a 9-year dataset from the Qinghai–Tibet Plateau (QTP) in conjunction with the GEOtop model, we demonstrate that the ratio λt/λf may approach or even exceed 1. This can happen in thick (> 1.5 m) active layers with strong seasonal total water content changes in the regions with summer-monsoon-dominated precipitation pattern. The conductivity ratio can be further increased by typical soil architectures that may lead to a dry interlayer. The unique pattern of soil hydraulic and thermal dynamics in the active layer can be one important contributor for the rapid permafrost warming at the study site. These findings suggest that, given the increase in air temperature and precipitation, soil hydraulic properties, particularly soil architecture in those thick active layers must be properly taken into account in permafrost models.


2019 ◽  
Vol 8 (10) ◽  
Author(s):  
Rui Xing ◽  
Qing‐bo Gao ◽  
Fa‐qi Zhang ◽  
Jiu‐li Wang ◽  
Shi‐long Chen

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2269
Author(s):  
Jinlong Li ◽  
Wei Wang ◽  
Dahao Wang ◽  
Jiaqi Li ◽  
Jie Dong

Thermokarst lakes are a ubiquitous landscape feature that impact the thermal state, hydrological process, ecological environment, and engineering stability of the permafrost. This study established the hydrochemistry and stable isotope (δ18O and δD) variations of lake water and groundwater in a typical basin located in the central Qinghai–Tibet Plateau (QTP) of China. The results showed that most water samples could be classified as slightly alkaline, with high levels of salinity and hardness, while the dominant water types were HCO3-CO3 and Cl types. Natural hydrochemical processes, such as mineral dissolution, cation exchange, and groundwater evaporation, had strong impacts on the groundwater chemistry in this region. Dissolution of halite and carbonate minerals causes the major reactions controlling water chemistry in this basin. Additionally, the calculation of the saturation index (SI) values suggested that aragonite, calcite, and dolomite are saturated, while halite is not. Based on the analysis of the stable isotope characteristics, atmospheric precipitation, groundwater, and meltwater from the permafrost are the major sources of thermokarst lakes. Moreover, the evaporation-to-inflow ratio (E/I) indicated that all of the lakes continuously expanded and rapidly developed. Overall, groundwater is an crucial source of lake recharge and its hydrochemical characteristics also have a certain impact on lake water quality.


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