Surface Heat Flow Research Articles

Does a Shallow Magma Reservoir Exist in the Wudalianchi Volcanic Field? Constraints From Magnetotelluric Imaging

AbstractWe obtain new images of the 3D resistivity structure of the Wudalianchi volcanic field (WVF). No low‐resistivity structure is found beneath Laoheishan and Huoshaoshan volcanoes in the WVF, which challenges the hypothesis of one or more magma reservoirs in the upper crust of this region. We observe a low‐resistivity body beneath Weishan volcano; however, estimated magma emplacement rates conflict with the observed volume of that body. Due to the relatively low geothermal gradient and surface heat flow in the area, magma would cool rapidly and could not be sustained for a long time unless new magma was regularly introduced into the system, but our observations do not support this scenario. We suggest that the magma in the WVF mainly originates from the mantle or the base of the crust with little crustal residence, and that the low‐resistivity body in the upper crust is likely due to saline aqueous free fluids.

Lithospheric Structure of the Circum‐Pannonian Region Imaged by S‐To‐P Receiver Functions

AbstractThe lithosphere‐asthenosphere boundary and mid‐lithospheric discontinuities are primary attributes of the upper mantle. The Pannonian region is an extensional sedimentary basin enclosed by collisional orogens. Here, we estimate the negative phase depth of S‐to‐P receiver functions to image the lithospheric thickness and other discontinuities with high resolution, based on the recent dense seismological broadband networks. The lithosphere‐asthenosphere boundary is relatively shallow (<90 km) in the Pannonian Basin system, and deeper (∼90–140 km) in the surrounding orogens, where average surface heat flow values are higher (120 mW/m2) and lower (50–70 mW/m2), respectively. The 1D and 2D common conversion point migration with 3D velocity model provide comparable but different resolution images beneath the wider region of the Pannonian Basin. We obtained deeper values in the Western (∼120 km) and Southern‐Carpathians orogens (∼135 km). Furthermore, we provide new information on the lithospheric thickness and its seismic properties in the eastern part of the study region (e.g., Apuseni Mountains (∼95 km), Eastern‐Carpathians (∼120 km), Moesian Platform (∼90 km) and Transylvanian Basin (∼85 km). The shallower negative phase depth can be interpreted as the lithosphere‐asthenosphere boundary beneath the Pannonian Basin system in agreement with its high heat flow values. In contrast, the deeper negative phase depth estimates in the colder surroundings can be interpreted as intra‐ or mid‐lithospheric discontinuities, when compared with local seismic tomography models. In this region, the correlation with heat flow implies that the observed negative phase depth is of thermo‐chemical or rheological nature.

Mapping the Structure and Metasomatic Enrichment of the Lithospheric Mantle Beneath the Kimberley Craton, Western Australia

AbstractThe lithology, geochemistry, and architecture of the continental lithospheric mantle (CLM) underlying the Kimberley Craton of north‐western Australia has been constrained using pressure‐temperature estimates and mineral compositions for >5,000 newly analyzed and published garnet and chrome (Cr) diopside mantle xenocrysts from 25 kimberlites and lamproites of Mesoproterozoic to Miocene age. Single‐grain Cr diopside paleogeotherms define lithospheric thicknesses of 200–250 km and fall along conductive geotherms corresponding to a surface heat flow of 37–40 mW/m2. Similar geotherms derived from Miocene and Mesoproterozoic intrusions indicate that the lithospheric architecture and thermal state of the CLM has remained stable since at least 1,000 Ma. The chemistry of xenocrysts defines a layered lithosphere with lithological and geochemical domains in the shallow (<100 km) and deep (>150 km) CLM, separated by a diopside‐depleted and seismically slow mid‐lithosphere discontinuity (100–150 km). The shallow CLM is comprised of Cr diopsides derived from depleted garnet‐poor and spinel‐bearing lherzolite that has been weakly metasomatized. This layer may represent an early (Meso to Neoarchean?) nucleus of the craton. The deep CLM is comprised of high Cr2O3 garnet lherzolite with lesser harzburgite, and eclogite. The peridotite components are inferred to have formed as residues of polybaric partial mantle melting in the Archean, whereas eclogite likely represents former oceanic crust accreted during Paleoproterozoic subduction. This deep CLM was metasomatized by H2O‐rich melts derived from subducted sediments and high‐temperature FeO‐TiO2 melts from the asthenosphere.

GLOBAL GEODYNAMIC MODEL OF THE EARTH AND ITS APPLICATION FOR ANTARCTICA

A geodynamic model of the modern Earth is constructed based on the SMEAN 2 global seismic tomography model. On the basis of mantle temperature anomalies, numerical modeling of spherical mantle convection is performed for the parameters of the real Earth. For Antarctica, an explanation was obtained for the existence of the West Antarctic Rift System, which contains one of the largest and least known volcanic provinces on Earth, which is consistent with the increased surface heat flow and modern volcanism of the West Antarctic Rift System and part of the Antarctic Peninsula. The increased heat flow and volcanoes in this region are causing instability and accelerating the flow of glaciers from the West Antarctic Ice Sheet into the ocean, which could lead to a significant rise in global sea level.

Present geothermal field of the Santos Basin, Brazil

The Santos Basin, located in the southeastern waters of Brazil, is a passive continental margin basin with the most abundant deepwater petroleum resources in the world discovered to date. However, few studies have been conducted on the present geothermal fields of the Santos Basin, which severely restricts the oil and gas resource evaluation of the basin. This study first utilizes 35 temperature data from 16 post-salt drilling wells and 370 temperature data from 31 pre-salt drilling wells to calculate the post-salt and pre-salt geothermal gradients and terrestrial heat flows in the Santos Basin. Then, the basin simulation software BasinMod 1D is used to quantitatively evaluate the impacts of salt rock sedimentation on the present geothermal fields and the maturity of pre-salt hydrocarbon source rocks. The results demonstrate that the present post-salt geothermal gradient in the Santos Basin is 2.20–3.97 °C/100 m, with an average value of 2.99 °C /100 m, and the post-salt terrestrial heat flow is 54.00–97.32 mW/m2, with an average value of 73.36 mW/m2, while the present pre-salt geothermal gradient is 2.21–2.95 °C/100 m, with an average value of 2.53 °C/100 m, and the pre-salt terrestrial heat flow is 61.85–82.59 mW/m2, with an average value of 70.69 mW/m2. These values are characteristic of a low-temperature geothermal field in a zone with a stable structure. The sedimentation of the salt rock causes a decrease in the temperature of the pre-salt strata, which inhibits pre-salt hydrocarbon source rock maturity, with an inhibition rate of up to 1.32%. The inhibition degree decreases with increasing salt rock thickness. At the same time, the salt rock thickness is positively correlated with the present surface heat flow. The unique distribution of the salt rock and related salt structures lead to present terrestrial heat flow differences among different structural units in the basin. This study is of great significance for evaluating and exploring the pre-salt oil and gas resources in the Santos Basin.

Tectonic controls on effective elastic thickness of lithospheres around the Southeast Asian subduction zones

Southeast Asia has the most complicated convergent system on the Earth. The effective elastic thickness (Te) can be a constraint on the long-term flexural strength and deformation mechanism of the lithosphere. In this paper, we estimate Te over the Southeast Asia via the free-air admittance function calculated by the continuous wavelet transform. Sedimentary correction is performed to avoid the biases induced by the low density of sediments. The spatial variations of Te coincide well with the tectonic settings. The Northeast Indian Seamount Province and young oceanic basins correspond to the lowest Te (≤10km). The Sunda Shelf displays relatively low Te (10–20 km), where Cenozoic rifting and extension weakened the lithosphere. The Molucca Sea and most continental regions show high Te (≥40 km). Overall, Te shows dependence on the oceanic crustal age in our study area, and is influenced by intensive tectonic activities. Low Te (≤10km) in northern Sumatra and central Java subduction zone is consistent with the presence of a slab tear/window and mantle upwelling. Moreover, Te in Southeast Asia is either non-correlated with surface heat flow, or weakly correlated to Curie-point depth and seismic velocities at the 100 km depth. In some regions, e.g., the South China Sea and Sumatra-Java Trench, Te shows poor correlation with all geothermal proxies we employed. We argue that the geothermal state of lithosphere exerts very limited effects on integrated lithospheric strength in the tectonically active Southeast Asia, and apart from the temperature and composition, tectonic factors dynamically control the rigidity of the lithosphere.

Thermal structure beneath Changbaishan Volcano, northeastern Asia: new insights from temperature logging and numerical modelling

SUMMARY Changbaishan Volcano is considered one of the most hazardous active volcanic fields in northeastern Asia, and it has been the subject of increasing concern due to its unrest from 2002 to 2006. The physical conditions of magma chambers in the crust, particularly temperature and pressure, are crucial factors that determine the tempo and magnitude of volcanic eruptions, which are closely linked to potential hazards. However, the lithospheric thermal structure, which strongly influences rheological behaviour and melting, has been poorly studied. We conducted direct geothermal measurements and numerical forward modelling to address this issue to confirm whether a crustal magma chamber lies beneath the caldera as in earlier geophysical interpretations. We first reported four heat-flow data sets in Changbaishan Volcano. The research findings indicate that the heat flow value near the Tianchi caldera is remarkably high, at 270±16 mW m−2. As the distance from the caldera increases, the heat flow gradually decreases to a normal continental heat flow value of 75 mW m−2. 3-D transient heat simulations with a magma cooling model and a continuous magma supply model demonstrate the thermal effect of the magma chamber. The best-fitting model for the Tianchi magma system is an ellipsoidal magma chamber with a depth of 8–14 km, a 20 km east–west axis and a 70 km north–south axis, supplied with magma from the asthenosphere for 2 Myr. The high surface heat flow and crustal temperatures suggest that magma is active beneath Changbaishan Volcano within the middle-upper crust, and volcanic reactivation could occur. Thus, further research on the lithospheric thermal structure is necessary to understand the potential volcanic hazards associated with Changbaishan Volcano.

A high geothermal setting in the Linyi geothermal field: Evidence from the lithospheric thermal structure

The lithospheric thermal structure has a profound indicative significance for the potential evaluation and exploration of geothermal resources. The Linyi geothermal field, located in the southern section of the Yishu fault in Shandong Province, boasts abundant geothermal resources. However, its origin is still unclear. This study analyzed the characteristics of terrestrial heat flow using the temperature logging of geothermal wells and measurements of thermal conductivity and heat production. Combined with the geophysical information of the Xiangshui (Jiangsu Province)-Mandula (Nei Mongol) geoscience transect and the lithology revealed by the geothermal wells, this study built a conceptual model of the lithospheric thermal structure using the one-dimensional steady-state heat conduction equation. Based on this model, the heat flow is 64.9 mW/m2, indicating a high geothermal setting in the study area. Furthermore, the ratio of crustal to mantle heat flow is < 1 (0.67), implying that surface heat flow originates predominantly from the mantle. The Yishu fault probably acts as a pathway for heat transfer from the mantle. The temperature of the Moho boundary in the study area was estimated to be 614.8 °C. The Curie depth was calculated to be 29.5 km (585 °C), which is consistent with the depth estimated using the aeromagnetic data. In sum, the Linyi geothermal field has a high geothermal setting, which contributes to the formation of geothermal resources.

The disparities in thickness between the thermal and seismic lithosphere beneath the global Precambrian cratons and its geodynamic implications

Cratons play an important role in the evolution of Earth and usually exhibit extremely thick and strong lithosphere roots and low surface heat flow. Most cratons remain in a stable state throughout their long evolutionary process. However, the stability of a few cratons was lost, the thickness of the lithosphere was greatly reduced, and surface heat flow greatly increased. Significant thinning of the lithosphere is one of the most obvious features of craton destruction. However, even within the same area, the lithospheric thickness values estimated from different methods can vary a lot. The thickness disparities between the thermal and seismic lithosphere remain unclear. On the basis of the latest global heat flow data and crustal stratification information, we calculated the thickness of the thermal lithosphere of cratons globally and conducted a detailed comparison to that of the seismic lithosphere. We found that 1) the thickness of the thermal lithosphere of most cratons is more than 150 km, while that of the Bundelkhand, Singhbhum, and upper Yangtze craton ranges from approximately 120–150 km. The thickness of the eastern North China craton, lower Yangtze craton and Wyoming craton ranges from only approximately 80–100 km. 2) For most cratons, the thickness of the seismic lithosphere is tens of kilometers (30–141 km) larger than that of the thermal lithosphere, except for the Wyoming craton, eastern North China craton, upper Yangtze craton, and Dahawar craton. 3) The part between the bottom boundaries of the seismic and thermal lithosphere can be considered as the rheological boundary layer (RBL), which is related to the craton stability. The thicker the RBL is, the higher the craton stability. 4) Due to plate subduction, the water content in the upper mantle is high, the viscosity is low, and the thickness of the RBL of cratons is small.

Study on the Thermal Distribution Characteristics of a Molten Quartz Ceramic Surface under Quartz Lamp Radiation.

More and more researchers are studying the heat transfer performance of aeronautical materials at high temperatures. In this paper, we use a quartz lamp to irradiate fused quartz ceramic materials, and the sample surface temperature and heat flux distribution were obtained at a heating power of 45~150 kW. Furthermore, the heat transfer properties of the material were analyzed using a finite element method and the effect of surface heat flow on the internal temperature field was investigated. The results show that the fiber skeleton structure has a significant effect on the thermal insulation performance of fiber-reinforced fused quartz ceramics and the longitudinal heat transfer along the rod fiber skeleton is slower. As time passes, the surface temperature distribution tends to stability and reaches an equilibrium state. The surface temperature of fused quartz ceramic increases with the increase in the radiant heat flux of the quartz lamp array. When the input power is 5 kW, the maximum surface temperature of the sample can reach 1153 °C. However, the non-uniformity of the sample surface temperature also increases, reaching a maximum uncertainty of 12.28%. The research in this paper provides important theoretical guidance for the heat insulation design of ultra-high acoustic velocity aircraft.

Crust-mantle differentiation and thermal accumulation mechanisms in the north China plain

The North China Plain, which is the central part of the lithospheric thinning in the North China Craton, is rich in clean geothermal energy. However, a current lack of understanding about the thermal accumulation mechanisms of the deep geothermal resources in this area is hindering the exploration, exploitation, and utilization of these resources and the achievement of the carbon reduction targets. Based on deep drilling and the tests of thermal property parameters at different depths, this study calculated the terrestrial heat flow and the heat flux at different depths of the lithosphere in the North China Plain and revealed the lithosphere thermal structure characteristics and the thermal accumulation mechanisms in the plain, obtaining the following results. The North China Plain has widely varying terrestrial heat flow of 33.5–92.1 mW/m2 (average: 62.1 ± 17.04 mW/m2). The average mantle heat flow and crustal heat flow in the plain are 42.05 ± 13.90 mW/m2 and 20 mW/m2, respectively, which account for approximately 67% and 33% of the total surface heat flow in the plain, respectively. This plain has a greatly varying Moho depth of 30–40 km and a Moho temperature of 420–920 °C mostly. The thermal lithosphere in the North China Plain has a thickness of 80–100 km and a thermal structure of the cold crust and hot mantle type. It has thinned on a large scale due to the extensional process, and the mantle-derived materials have migrated upward along the weak structural plane (e.g., deep faults) after pressure release and remelting. The resultant high mantle heat flow serves as a stable heat source for the formation of layered medium-low temperature geothermal fields.

Distribution of surface heat flow and effects on the subsurface temperatures in the northern part of Thrace Basin, NW Turkey

The Thrace Basin in northwestern Turkey is a deep Eocene–Oligocene hydrocarbon-bearing sedimentary basin. The basin has potential for geothermal energy utilization in the future due to its favorable geological conditions. In this study, we combined the available bottom hole temperature (BHT) data from 70 points with the thermal conductivity and radiogenic heat productions of the basin formations, and generated a detailed thermal model of the northern part of the basin. For heat flow determinations from the BHT data, we applied Bullard’s thermal resistance method on formation thermal conductivities and thicknesses. The results give an average surface heat flow of 65.8 ± 11.3 mW/m2. We obtained high heat flow values (75–80 mW/m2) in the eastern and western sides, and the central part of the study area. These relatively high heat flow values can be explained by the combined effect of basement topography and the variations in the radiogenic heat production of the basement rocks. The calculated subsurface temperatures in selected hydrocarbon fields vary in the range of 45–64 °C at 1 km depth, 99–136 °C at 3 km depth, and 155–208 °C at 5 km depth as a result of local variations of the surface heat flow and formation thermal resistances. These variations in subsurface temperatures can have significant effects on the cost of geothermal energy production in future.

A Set of Geophysical Fields for Modeling of the Lithosphere Structure and Dynamics in the Russian Arctic Zone

This paper presents a set of various geological and geophysical data for the Arctic zone, including some detailed models for the eastern part of the Russian Arctic zone. This hard-to-access territory has a complex geological structure, which is poorly studied by direct geophysical methods. Therefore, these data can be used in an integrative analysis for different purposes. These are the gravity field, heat flow, and various seismic tomography models. The gravity field data include several reductions calculated during our preceding studies, which are more appropriate for the study of the Earth’s interiors than the initial free air anomalies. Specifically, these are the Bouguer, isostatic, and decompensative gravity anomalies. A surface heat flow map included in the dataset is based on a joint inversion of multiple geophysical data constrained by the observations from the International Heat Flow Commission catalog. Available seismic tomography models were analyzed to select the best one for further investigation. We provide the models for the sedimentary cover and the Moho depth, which are significantly improved compared to the existing ones. The database provides a basis for qualitative and quantitative analysis of the region.

Lithospheric Elastic Thickness Beneath the Caloris Basin: Implications for the Thermal Structure of Mercury

AbstractThe elastic thickness of a planet's lithosphere is essential to the investigation of its thermal evolution. Our work focuses on the largest visible impact basin on Mercury, Caloris, which has undergone complex magma‐tectonic deformation after its formation. Using a flexural lithosphere model with the initial mantle plug loading, we estimated the elastic thickness in the Caloris region to be 18.0 4.4 km. The successful application of the mantle loading model and the small load ratio indicates that major load in the Caloris region is the mantle plug rather than the lateral density anomaly. The 18 km effective elastic thickness indicates the lithospheric temperature at the time of loading. The current heat production rate in Mercury mantle is estimated as 2.2–4.2 × 10−12 W/kg. Comparison between the effective elastic thickness predicted from the thermal model and loading model suggests that the megaregolith in the Caloris basin region has a certain thickness (>3 km) to ensure the formation of a lithosphere with 18 km elastic thickness. The temperature model results also indicate that the mantle heat production rate at 3.6 Ga is closer to that calculated based on a model with heat‐producing elements abundance close to CI chondrite‐like primitive silicate portion of Mercury. The surface heat flow in the Caloris region is consistent with other megaregolith‐covered regions.

Curie Depth and Surface Heat Flow Estimation from Anomalous Magnetic Blocks in the Lower and Part of Middle Benue Trough and Anambra Basin

Estimation of the bottom (Curie) depths and SHF values on blocks (A, B, C, …, Y) of magnetic anomalies in the lower and part of the middle Benue trough and Anambra basin have been presented. A Map of the result shows a shallow Curie depth of about 11 km around the area of Abakaliki with the deepest Curie depth of about 27 km obtained around Utukpa region. The overriding bottom (Curie) depth of 18 km is calculated around Iku mbur, Arufu and Igumale regions. Heat flow has also been calculated from the Curie depth results. The SHF vary from 54 mWm–2 around Utukpa to the highest value of 132 mWm–2 around Abakaliki. The obtained high SHF value could be of sufficiently good prospects for the exploration of geothermal energy resources in the region.

The Study of the Lithospheric Magnetic Field over Xinjiang and Tibet Areas Based on Ground, Airborne, and Satellite Data

Combined with the ground, airborne, and CHAMP satellite data, the lithospheric field over Xinjiang and Tibet is modeled through the three-dimensional Surface Spline (3DSS) model, Regional Spherical Harmonic Analysis (RSHA) model, and CHAOS-7.11 model. Then, we compare the results with the original measuring data, NGDC720, LCS-1, and the newest SHA model with the degree to 1000 (SHA1000). Moreover, the error estimation and the geological analysis are carried out, and we investigate the possible correspondence between the lithospheric field and the surface heat flow. The results show that the 3DSS model can better describe the detailed distribution of the lithospheric field after comparing it with other models. Some new features are reflected, particularly in the areas of Southern Xinjiang and Tibet, such as a positive anomaly stripe in the southwest, its neighboring Tashkurgan–Hotan–Cele–Minfeng–Qiemo–Ruoqiang belt, and the middle edge of the Kunlun Mountains. The stripe, in terms of rock composition, has a shallow magnetic field source and is related to magnetic intrusions; the lithospheric field in Tibet is weak. Additionally, when the heat flow distribution is compared to our results, there is a good consistency between a positive stripe of heat flow and a positive stripe of the lithospheric field in southern Tibet. The large heat flow values may be related to the shallow Curie surface, which shows that demagnetization is happening close to the surface. However, more of a ferromagnetic mineral, Titanium magnetite, is found there.

The coherence function and lithospheric elastic thickness of the Zagros fold and thrust belt

SUMMARY This study derives the spatial variation of the elastic thickness (Te) and its implications for understanding the structure, geodynamic and seismicity of the lithosphere for the Zagros fold and thrust belt region of the Arabia–Eurasia collision zone. Te is calculated using the coherence function in the fan wavelet domain based on recent terrestrial Bouguer gravity and topography data as input signals. Utilizing the load deconvolution method and Brent's method of 1-D minimization, the final Te for the survey region is estimated for each grid node of the studied area. To illustrate the mass distribution in the studied area, the subsurface loading fraction (F) is calculated simultaneously with Te in the inversion. The crust thickness and density from three different global crustal models are tested and the results obtained for these input models do not yield substantially different Te patterns. The final results are in accord with the global Te models as well as previous rheological, geodynamical and flexural studies, however, this study establishes much more detailed regional information. The calculations yield a mean value of Te of 61 km for the Zagros, with a mean estimated error of about 5 km. The high-Te values (>70 km) are observed in the southeast of the studied area (some parts of the Sanandaj–Sirjan zone, Urumieh–Dokhtar magmatic arc and most of the Central Iranian blocks); while over most of the northwest of the studied area, the value of Te is about 58 km. The Te results are consistent with the lithospheric structure of the study area and also support the idea of the crust–mantle decoupling. Further, there is a positive and negative correlation between the surface wave velocity and surface heat flow, respectively. The mean value estimated for the internal loading friction (F) of 0.4 means in most of the studied areas we may consider that the surface loading is dominant, or at least the ratio of the surface and subsurface loading can be assumed equal. Based on earthquake distribution in the period 1900–2020, seismicity is more likely to occur in areas with a relatively low value of Te.

Update and Review of Continental Conductive Surface Heat Flow Measurements in México: An Analysis of Deep Boreholes

Update and Review of Continental Conductive Surface Heat Flow Measurements in México: An Analysis of Deep Boreholes

Heat flow variations in 2 km deep borehole Litoměřice, Czechia

Temperature in 2 km deep borehole Litoměřice, drilled in 2007, was repeatedly logged down to 1700 m in the period 2007 – 2020. We were able to monitor a return of the temperature to the equilibrium temperature-depth profile undisturbed by drilling. The uppermost part of the profile contains signal of the recent warming manifested by a negative temperature gradient close to the surface and a temperature minimum at a depth of about 40 m. The minimum has been migrating downward at a rate of 1.5 – 2 m per year in the period 2015 – 2020.A detailed knowledge of temperature gradient together with thermal conductivity, diffusivity and heat production measurements on the drill-core samples of mica-schist that occurs below 900 m depth enabled us to analyze the heat flow vertical variations in the lithologically homogeneous depth section 900 – 1700 m. We came to the conclusion that temperature-depth profile in this section contains a robust climate signal of the last glacial cycle. The reconstructed ground surface temperature history indicates the magnitude of the last glacial – Holocene warming 13 -15 K and existence of a minimum 15 – 20 ka. The long-term mean ground surface temperature +1 - +2 °C suggests that the borehole site was permafrost free for most of the glacial cycle. Existence of about 100 m deep permafrost is possible in the coldest part of the last glacial.The steady-state surface heat flow has been estimated at 88 mW/m2. The reconstructed ground surface temperature history used as a surface forcing function in a numerical solution of the transient heat conduction equation provided an estimate of the present-day heat flow in the well. The estimate is practically independent from the poorly constrained conductivity of the 900 m thick sedimentary cover. According to it the present-day heat flow is lower than the steady-state one by 20 - 30 mW/m2 in the first hundreds of meters below the surface and still by about 10 mW/m2 at a depth of 1 km.

Strong Variability in the Thermal Structure of Tibetan Lithosphere

AbstractWe present a model of thermal lithospheric thickness (the depth where the geotherm reaches a temperature of 1300°C) and surface heat flow in Tibet and adjacent regions based on a new thermal‐isostasy method. The method accounts for crustal density heterogeneity, is free from any assumption of a steady‐state lithosphere thermal regime, and assumes that deviations from crustal Airy‐type isostasy are caused by lithosphere thermal heterogeneity. We observe a highly variable lithospheric thermal structure which we interpret as representing longitudinal variations in the northern extent of the subducting Indian plate, southward subduction of the Asian plate beneath central Tibet, and possible preservation of fragmented Tethyan paleo‐slabs. Cratonic‐type cold and thick lithosphere (200–240 km) with a predicted surface heat flow of 40–50 mW/m2 typifies the Tarim Craton, the northwest Yangtze Craton, and most of the Lhasa Block that is likely refrigerated by underthrusting Indian lithosphere. We identify a “North Tibet anomaly” with thin (<80 km) lithosphere and high surface heat flow (>80–100 mW/m2). We interpret this anomaly as the result of removal of lithospheric mantle and asthenospheric upwelling at the junction of the Indian and Asian slabs with opposite subduction polarities. Other parts of Tibet typically have intermediate lithosphere thickness of 120–160 km and a surface heat flow of 45–60 mW/m2, with patchy anomalies in eastern Tibet. While different uplift mechanisms for Tibet predict different lithospheric thermal regimes, our results in terms of a highly variable thermal structure beneath Tibet suggest that topographic uplift is caused by an interplay of several mechanisms.