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Research on the type, size, structure, and other characteristics of shale micro pore-fracture and their genesis is one of the core index for Shale gas study. Based on systematically collected shale samples from outcrop profiles and well cores, the experiments of thin-section observation, scanning electron microscopy, energy-dispersive X-ray spectroscopy, whole-rock analysis, rock–eval pyrolysis and basin simulation analysis were performed to study the micro pore-fracture characteristics and its main controlling factors for the development of shale pores in Tiemulike Formation in Yining Basin. The results show that four types of micro pore-fractures were identified: organic hydrocarbon-generating micro pores, granular dissolved micro pores, intergranular micro pores, and micro-fracture. The development of micro pores in shales is influenced by the internal material composition of the shale reservoir and external temperature conditions. The high organic carbon content with a high degree of thermal evolution led to the development of numerous micro pores, and the main micro pores were produced by shrinking the hydrocarbon generation volume due to the thermal evolution of organic matter. The development of micro-fractures was found to be favoured by the high content of brittle minerals and overpressure in the formation. [ABSTRACT FROM AUTHOR]

Lunar mare basalts represent melting of mantle material, buoyant ascent in dikes, and eruption onto <20% of the surface. Global mare distribution is distinctly asymmetrical, with a paucity on the farside, plausibly interpreted to be related to thicker farside low‐density crust inhibiting buoyant magma rise to the surface. Challenging this hypothesis is the presence of the huge, ancient farside South Pole‐Aitken (SPA) basin, site of the thinnest crust and deepest depression observed on the Moon. We hypothesize that an oblique impact stripped the farside crust within the SPA basin, permitting early mare basalt emplacement as cryptomaria due to thin/absent crust. However, removal of the SPA thermally insulating megaregolith/crust accelerated lithosphere thickening beneath the basin. This deepening rheological barrier inhibited buoyant rise of mantle diapirs below SPA, resulting in early abatement of mare basalt extrusions compared to the nearside, and retention of the deep, underfilled SPA impact basin observed today. Plain Language Summary: The cause of the observed asymmetry in nearside/farside mare basalt distribution (nearside ∼15% of the surface, farside ∼1%) has been attributed to differences in crustal thickness and the magma buoyancy at the base of the thicker crust, but this single factor is challenged by the presence of the ancient very deep SPA basin (average ∼5 km), significantly underfilled by mare basalts compared to the nearside. We examine the effects of the formation of the giant (∼2,300 km) SPA basin in removing the insulating megaregolith/crust, and show that it could first result in rapid cryptomaria emplacement due to near‐absent crust, accompanied by enhanced heat loss within the basin, and formation of anomalously early thick sub‐SPA lithosphere, inhibiting its mare filling due to a rheological barrier to basaltic magma eruptions, analogous to that which occurs later in lunar history on the lunar nearside. Key Points: The nearside‐farside asymmetry in mare basalt volcanic deposits has been attributed to thicker farside crust inhibiting eruptionChallenging this hypothesis is the very deep, thin‐crust ancient SPA impact basin, significantly underfilled by mare basaltsAfter SPA impact‐removal of insulating crust, sub‐SPA lithosphere thickens anomalously early, inhibiting mare fill following cryptomaria [ABSTRACT FROM AUTHOR]

Mercury's low obliquity and 3:2 spin‐orbit resonance create a surface temperature distribution with large latitudinal and longitudinal variations. These propagate via thermal conduction through the thin silicate shell influencing the interior temperature distribution. We use 3‐D thermal evolution models to investigate the effects of lateral variations of surface temperature and crustal thickness on the surface and core‐mantle boundary (CMB) heat fluxes, and elastic thickness distribution. Surface temperature variations cause a long‐wavelength perturbation of the heat fluxes, as well as of the elastic lithosphere thickness, while variations in crustal thickness affect these quantities at small spatial scales. Like the surface temperature, the present‐day CMB heat flux pattern is characterized primarily by spherical harmonics of degrees two and four, which could affect dynamo generation. Placing robust constraints on the thermal evolution based on the available estimates of the age and thickness of the elastic lithosphere remains challenging due to their large uncertainties. Plain Language Summary: The orbit of Mercury around the Sun leads to a specific surface temperature distribution, with some regions receiving more insolation than others. The thickness of Mercury's crust has been derived using gravity and topography data acquired by the MESSENGER mission. Since the rocky mantle of Mercury is rather thin (≈ ${\approx} $400 km), temperature variations driven by the insolation and by crustal properties (i.e., crustal heat sources and thermal conductivity) can affect the entire mantle, down to the core‐mantle boundary. Here we model the global thermal evolution of Mercury, and investigate the influence of surface temperature and crustal thickness variations on the history and present‐day state of the interior. We find that the surface temperature variations are reflected in the variations of Mercury's surface and core‐mantle boundary heat fluxes, as well as in the thickness of the elastic part of its lithosphere. Crustal thickness variations lead to more local temperature differences, thus resulting in smaller scale variations in the lithosphere thickness and heat fluxes. The heat flux pattern at the core mantle boundary induced by the surface temperature distribution could affect magnetic field generation and should be tested by future dynamo models. Key Points: The distribution of Mercury's mantle temperature is strongly influenced by surface temperature and crustal thickness variationsSurface heat flux and elastic thickness are controlled at large scales by surface temperature, and at small scales by crustal thicknessSurface temperature variations influence the CMB heat flux distribution, which we make readily available to test dynamo models [ABSTRACT FROM AUTHOR]

Based on low temperature nitrogen adsorption experiment, the quantitative characterization of Marine mud shale from Qiongzhusi formation of the lower Cambrian and Longmaxi formation of the lower Silurian in the Upper Yangzi Massif and Terrestrial mud shale of chang 9 and chang7 oil layers in Ordos Basin is finished. The pore characteristics and influencing factors of shale reservoirs with different sedimentary environments and maturity are discussed systematically from the aspects of material composition and thermal evolution. The results show that the brittle mineral content is negatively correlated with the specific surface area and pore volume. The content of clay minerals is weakly positively correlated with specific surface area and pore volume. TOC content is weakly positively correlated with pore volume, strongly positively correlated with specific surface area, and not correlated with average pore diameter. With the increasing of Ro, the average pore diameter decreases, and the decreasing speed decreases with the increasing of Ro. When Ro is between 0.5% and 2.8%, the specific surface area increases with Ro. When Ro is between 2.8% and 5%, the specific surface area decreases with the increase of Ro. The pore volume was negatively correlated with Ro value due to the decrease of pore diameter. [ABSTRACT FROM AUTHOR]

Reconstructing the thermal evolution of the eastern Qaidam Basin is important for gaining a deeper understanding of its lithospheric geodynamics and for more accurate hydrocarbon evaluation and prediction. This article presents a set of new apatite and zircon (U-Th)/He thermochronological ages. Combined with 336 vitrinite reflectance (Ro) data, the thermal history of the Ouanan Sag in the eastern Qaidam Basin has been reconstructed using inversion models. Three detrital samples from the Ounan Sag shows that the apatite (U-Th)/He ages are primarily concentrated in the range of 17.0 Ma to 76.5 Ma and that the zircon (U-Th)/He ages range from 200 Ma to 289.3 Ma. The time-temperature models demonstrate that the Ounan Sag experienced rapid subsidence and heating from the Carboniferous to late Permian, and exhumation/cooling events from the end of Permian to the Triassic. This thermal evolution was influenced by the widespread intrusion of plutons, and the collision and orogenesis caused by asthenosphere upwelling below the Qaidam arc, and slab rollback of the Southern Kunlun oceanic lithosphere, respectively. Additionally, our models depict the main exhumation/cooling stages since the Paleogene and a reheating event in the Miocene as a result of the intensifying growth of the Qinghai eTibet Plateau and local sedimentary loading, followed by the initial IndiaeEurasia collision. Furthermore, the eastern Qaidam Basin experienced consistent heating during the late Paleozoic, reaching the maximum paleotemperature and geothermal gradient in the late Permian, with values of ~230 ℃ and ~43e44 ℃/km, respectively. This study suggests that the source rocks in the most upper member of upper Carboniferous Keluke (C2k) Formations in the Ounan Sag reached the gas generation stage in the late Permian. [ABSTRACT FROM AUTHOR]

In the automotive industry, short glass fiber-reinforced thermoplastics are widely used under the hood and subjected to dynamic vibrations of the engine in multiple directions resulting in fatigue failure. Under fatigue loading, a significant portion of the strain energy is stored within the material, while the remaining portion is lost due to internal frictions and the damage occurrence. Internal friction results in heat generation, which in turn causes an increase in external temperature. This increase in temperature leads to thermal degradation of the polymer. Investigations on the cause of the stiffness drop are not widely available in the literature. Therefore, this study explores the source of the stiffness drop under biaxial fatigue loading of a polyamide 6,6 reinforced with 30 wt. % short glass fibers (PA66GF30) and distinguishes the contributions of thermal degradation and damage accumulation. The thermal evolution of the specimens was captured by means of thermography. In addition, the digital image correlation (DIC) technique was used to measure the in situ strain field during the fatigue. Despite the temperature stabilization being observed around the 10,000th cycle, the reduction in the stiffness continued until failure which was attributed to the mechanical damage accumulation and cyclic creep during the fatigue tests. Dynamic mechanical analyses (DMA) were carried out to quantify the stiffness drop with the varying temperature. From the results, it is seen that the damage accumulation and cyclic creep during the fatigue tests were responsible for the major part of the stiffness drop. Finally, scanning electron microscopy (SEM) inspection of the fracture surface was performed to identify fatigue damage mechanisms. Four unique features associated with the fatigue damage were identified: (1) debonding of fibers from the matrix, (2) polymer matrix crazing, and (3) cavitation and porosities, (4) pull out fiber ends and break on the fiber. [ABSTRACT FROM AUTHOR]

Linear gravity anomalies (LGAs) on the Moon have been interpreted as ancient magmatic intrusions formed during the lunar expansion. The composition of such ancient subsurface intrusions may offer hints for the lunar thermodynamic state in the initial stage of lunar history. To pose a first compositional constraint on magmatism related to lunar expansion, this study analyzed the spectrum and gravity around craters on LGAs, such as Rowland, Roche, and Edison craters. Using reflectance spectra around the craters, we first surveyed non‐mare basaltic exposures. To test the LGA excavation scenario as a possible origin of the discovered exposures, we then compared the Gravity Recovery and Interior Laboratory data and post‐cratering gravity simulation with the iSALE shock physics code. Our spectral analysis reveals no basaltic exposure around the Rowland crater. Further, the observed termination of LGA at the crater rim contradicts the gravity simulation, which assumes that LGA predates the Rowland crater. These results suggest that LGA formation might postdate the Rowland formation and that lunar expansion lasted even after the Nectarian age. On the other hand, we found that both Roche and Edison craters possess basaltic exposures in their peripheries. Because the gravity reduction inside Roche crater can be reproduced in our simulation, the discovered basaltic exposures are possibly LGA materials ejected from these craters. The composition of those exposures shows that the LGA intrusions at the two locations are composed of low‐titanium magma, indicating that ancient magma during the expansion did not contain ilmenite‐rich melt, perhaps resulting from the low‐ilmenite content of the ancient upper mantle. Plain Language Summary: The Moon has positive, narrow, and long gravity anomalies, so‐called linear gravity anomalies (LGAs), which are thought to be magmatic intrusions formed during the ancient lunar expansion. The composition of these intrusions may provide insights into the early lunar thermal state. This study analyzed the reflectance spectra and gravity data around craters located on LGAs, specifically Rowland, Roche, and Edison craters, which are postulated to have ejected the LGA material. By analyzing the reflectance spectra, we first identified non‐mare basaltic exposures that likely originated from these subsurface formations. We next examine if these exposures are composed of the LGA materials by comparing the observed gravity with cratering simulation results. We found no basaltic exposures around Rowland and that gravity inside Rowland is not consistent with the excavation hypothesis, perhaps suggesting that LGA formation and lunar expansion occurred after the Rowland formation. On the other hand, we discovered basaltic exposures around both Roche and Edison craters, which can be interpreted as ejecta from the LGAs consistent with the gravity inside Roche crater. The composition of these exposures indicates that LGAs are composed of low‐titanium magma, which provides a new constraint on the ancient thermal state of the Moon. Key Points: High‐calcium pyroxene exposures and gravity reduction around Roche crater imply an excavation of lunar linear gravity anomaly materialsLunar subsurface dikes formed during the ancient expansion stage are estimated to be composed of low‐titanium magmaA linear gravity anomaly possibly postdates the Rowland crater, suggesting a potential prolongation of lunar expansion beyond the Nectarian age [ABSTRACT FROM AUTHOR]

Abstract Research on the type, size, structure, and other characteristics of shale micro pore-fracture and their genesis is one of the core index for Shale gas study. Based on systematically collected shale samples from outcrop profiles and well cores, the experiments of thin-section observation, scanning electron microscopy, energy-dispersive X-ray spectroscopy, whole-rock analysis, rock–eval pyrolysis and basin simulation analysis were performed to study the micro pore-fracture characteristics and its main controlling factors for the development of shale pores in Tiemulike Formation in Yining Basin. The results show that four types of micro pore-fractures were identified: organic hydrocarbon-generating micro pores, granular dissolved micro pores, intergranular micro pores, and micro-fracture. The development of micro pores in shales is influenced by the internal material composition of the shale reservoir and external temperature conditions. The high organic carbon content with a high degree of thermal evolution led to the development of numerous micro pores, and the main micro pores were produced by shrinking the hydrocarbon generation volume due to the thermal evolution of organic matter. The development of micro-fractures was found to be favoured by the high content of brittle minerals and overpressure in the formation.

Abstract Deep shale has the characteristics of large burial depth, rapid changes in reservoir properties, complex pore types and structures, and unstable production. The whole-rock X-ray diffraction (XRD) analysis, reservoir physical property parameter testing, scanning electron microscopy (SEM) analysis, high-pressure mercury intrusion testing, CO2 adsorption experimentation, and low-temperature nitrogen adsorption–desorption testing were performed to study the pore structure characteristics of marine shale reservoirs in the southern Sichuan Basin. The results show that the deep shale of the Wufeng Formation Longyi1 sub-member in the Luzhou area is superior to that of the Weiyuan area in terms of factors controlling shale gas enrichment, such as organic matter abundance, physical properties, gas-bearing properties, and shale reservoir thickness. SEM is utilized to identify six types of pores (mainly organic matter pores). The porosities of the pyrobitumen pores reach 21.04–31.65%, while the porosities of the solid kerogen pores, siliceous mineral dissolution pores, and carbonate dissolution pores are low at 0.48–1.80%. The pores of shale reservoirs are mainly micropores and mesopores, with a small amount of macropores. The total pore volume ranges from 22.0 to 36.40 μL/g, with an average of 27.46 μL/g, the total pore specific surface area ranges from 34.27 to 50.39 m2/g, with an average of 41.12 m2/g. The pore volume and specific surface area of deep shale gas are positively correlated with TOC content, siliceous minerals, and clay minerals. The key period for shale gas enrichment, which matches the evolution process of shale hydrocarbon generation, reservoir capacity, and direct and indirect cap rocks, is from the Middle to Late Triassic to the present. Areas with late structural uplift, small uplift amplitude, and high formation pressure coefficient characteristics favor preserving shale gas with high gas content and production levels.

Nanoscratching introduces detrimental surface and subsurface defects like amorphous regions, dislocations, and stacking faults in monocrystalline silicon, hindering its application in microelectronics and high-performance optics. This study leverages in-situ transmission electron microscopy to unveil the thermal evolution of these defects in atomic scale. A key finding is the amorphous phase recrystallization starting at ∼500 °C. Epitaxial growth from the crystalline-amorphous boundary, guided by adjacent crystal planes, restores the original diamond structure phase. By 700–800 °C, almost complete recrystallization occurs, maintaining similar interplanar spacing despite residual crystal distortions and dislocations. Notably, heating above 600 °C results in the gradual vanishing of stacking faults, suggesting a dynamic thermal evolution of the crystal defects induced by surface nanoscratching. This work demonstrates thermal annealing as a promising strategy to mitigate nanoscratch-induced defects, paving the way for defect-free-surface of silicon components in ultra-precision machining processes. It offers valuable insights into the interplay between nanoscratching, temperature, and defect evolution, laying the groundwork for surface and subsurface defects elimination in silicon under thermal fields.

The porosity and pore structure of mud shales are crucial for shale oil and gas storage and transportation. Although the change of organic matter state in thermal evolution has a significant effect on pore formation, the mechanism and main controlling factors still need to be deeply explored. In this paper, we selected the shale of the Yanchang Formation in the southeastern Ordos Basin as an object, and used low-pressure N2/CO2 adsorption, He density method, high-pressure mercury compression, and field FE-SEM to deeply investigate the relationship between thermal evolution and pore development in organic matter-rich shale. The experimental results show that FE-SEM observation reveals that the organic matter pores of the shale in the Long 7 section of the Extension Formation show four developmental states, in which the organic matter in the undeveloped pores is mainly of higher plant origin, solid asphalt and laminated organic matter. The organic matter with highly developed pores is nanofibrous, similar to extracellular polymers. Comparison of thermal simulation experiments shows that the high-pressure semi-closed system has stronger hydrocarbon drainage strength than the closed glass tube system. In the oil generation stage, the pore volume of both systems decreased, mainly due to oil filling; while the oil cracking stage was the main pore development period, especially in the high-pressure semi-closed system; Simulation experiments with different organic matter types and contents showed that the mud shale with better organic matter type and TOC content was more prone to hydrocarbon drainage and pore growth. Compared with type II/II mud shale, type I and II are more likely to form macropores, and compaction has an inhibitory effect on the formation of macropores. This study reveals the close relationship between the pore development of mud shale and its thermal evolution of organic matter, which provides an important reference for shale oil and gas exploration. [ABSTRACT FROM AUTHOR]

We present a model for the thermal evolution of asteroids that experience catastrophic fragmentation and reassembly into a gravitational aggregate. The three stage model comprises the initial radiogenic heating, fragmentation and cooling, and reassembly into a porous gravitational aggregate. The heat loss during catastrophic fragmentation is largely determined by the production of small particles that equilibrate thermally with ambient space. To determine this heat loss we combine a power‐law for the cumulative fragment mass distribution with analytic solutions for conductive cooling. To keep the model deterministic we fragment the parent body and reassemble the gravitational aggregate in shells ordered in decreasing volume. We use the resulting model to show that catastrophic fragmentation can lead to significant heat loss despite the short reassembly times (e.g., ≤ ${\le} $1 year), due to the production of many small fragments. Despite the heat loss during fragmentation, the reassembled gravitational aggregate will retain more heat than the undisturbed parent body in the long term, due to the formation of an insulating megaregolith. Applied to the H‐chondrite parent body, our model can reproduce both the fast cooling rates at high temperatures and slow cooling rates at low temperature. Plain Language Summary: Ordinary chondrites are the most common rocky meteorites. Their parent body is generally assumed to follow the so‐called onion shell model where internal heating by radioactive decay warms up the interior and leads to concentric shells of different rock types. This model fits a large number of observations, for example, that these asteroids cooled very slowly at low temperatures. Recently, this quiet evolution has been challenged by the observation of very fast cooling rates from the peak temperature experienced by these asteroids. This requires that the asteroid is broken up into a large number of pieces by a collision with another asteroid. The fragments resulting from the collision can then cool rapidly as they are exposed to cold ambient space. A majority of these fragments must then assemble into a gravitational aggregate. The gravitational aggregate cools very slowly because it is insulated by a thick coat of rubble. Here, we develop a simple model to investigate the main consequences of fragmentation and reassembly into a gravitational aggregate for the thermal evolution of asteroids. Our results show that this is a viable model for the H‐chondrite parent body, consistent with both fast cooling at high temperature and slow cooling at low temperature. Key Points: Model quantifies the conductive heat loss due to asteroid catastrophic fragmentation as function to fragmentation level and reassembly timeDespite energy loss during fragmentation the formation of a low conductivity gravitational aggregate leads to long term energy retentionAsteroid fragmentation with reassembly can reproduce both fast cooling at high temperature and slow cooling at low temperature [ABSTRACT FROM AUTHOR]

The question of whether the present‐day mantle of Mercury is undergoing convection remains unresolved. We address this issue by estimating the minimum value of the core‐mantle boundary (CMB) temperature needed to support mantle convection and considering the time required to cool the mantle below this threshold. A simple mathematical analysis of the cooling of the core, based on the assumption of a quasi‐steady‐state thermal equilibrium of Mercury's mantle, shows that the CMB temperature falls to the critical temperature for cessation of convection roughly halfway through the planet's evolutionary history. To first order, the duration of subsolidus convection does not depend on the absolute value of the viscosity. It depends primarily on parameters that control the viscosity function, such as the stress exponent and the activation energy. Our results based on conventional assumptions suggest the absence of present‐day mantle convection in Mercury, which is consistent with numerical models of Mercury's thermal history. However, because of large uncertainties in the controlling parameters, the possibility of still ongoing mantle convection on Mercury cannot be ruled out. Plain Language Summary: We address the question of whether Mercury's mantle is currently convecting. We start by applying recent constraints on the onset of convection in fluids with variable viscosity to estimate the critical mantle temperature below which convection in Mercury's mantle stops. Then we derive simple formulas for the time required for the mantle to cool down to this critical temperature. These formulas allow us to analyze various factors controlling the cooling time and assess the conditions under which mantle convection may occur on Mercury today. Key Points: We constrain the critical conditions for the cessation of convection in Mercury's mantleWe derive approximate formulas for the time it takes mantle convection to cease during Mercury's evolutionMercury's mantle is likely not convecting at present; however, the uncertainties remain large [ABSTRACT FROM AUTHOR]

Predator responses to warming can occur via phenotypic plasticity, evolutionary adaptation or a combination of both, changing their top-down effects on prey communities. However, we lack evidence of how warming-induced evolutionary changes in predators may influence natural food webs. Here, we ask whether wild fish subject to warming across multiple generations differ in their impacts on prey communities compared with their nearby conspecifics experiencing a natural thermal regime. We carried out a common garden mesocosm experiment with larval perch (Perca fluviatilis), originating from a heated or reference coastal environment, feeding on zooplankton communities under a gradient of experimental temperatures. Overall, in the presence of fish of heated origin, zooplankton abundance was higher and did not change with experimental warming, whereas in the presence of fish of unheated origin, it declined with experimental temperature. Responses in zooplankton taxonomic and size composition suggest that larvae of heated origin consume more large-sized taxa as the temperature increases. Our findings show that differences between fish populations, potentially representing adaptation to their long-term thermal environments, can affect the abundance, biomass, size and species composition of their prey communities. This suggests that rapid microevolution in predators to ongoing climate warming might have indirect cross-generational ecological consequences propagating through food webs. [ABSTRACT FROM AUTHOR]

Deep shale has the characteristics of large burial depth, rapid changes in reservoir properties, complex pore types and structures, and unstable production. The whole-rock X-ray diffraction (XRD) analysis, reservoir physical property parameter testing, scanning electron microscopy (SEM) analysis, high-pressure mercury intrusion testing, CO2 adsorption experimentation, and low-temperature nitrogen adsorption–desorption testing were performed to study the pore structure characteristics of marine shale reservoirs in the southern Sichuan Basin. The results show that the deep shale of the Wufeng Formation Longyi1 sub-member in the Luzhou area is superior to that of the Weiyuan area in terms of factors controlling shale gas enrichment, such as organic matter abundance, physical properties, gas-bearing properties, and shale reservoir thickness. SEM is utilized to identify six types of pores (mainly organic matter pores). The porosities of the pyrobitumen pores reach 21.04–31.65%, while the porosities of the solid kerogen pores, siliceous mineral dissolution pores, and carbonate dissolution pores are low at 0.48–1.80%. The pores of shale reservoirs are mainly micropores and mesopores, with a small amount of macropores. The total pore volume ranges from 22.0 to 36.40 μL/g, with an average of 27.46 μL/g, the total pore specific surface area ranges from 34.27 to 50.39 m2/g, with an average of 41.12 m2/g. The pore volume and specific surface area of deep shale gas are positively correlated with TOC content, siliceous minerals, and clay minerals. The key period for shale gas enrichment, which matches the evolution process of shale hydrocarbon generation, reservoir capacity, and direct and indirect cap rocks, is from the Middle to Late Triassic to the present. Areas with late structural uplift, small uplift amplitude, and high formation pressure coefficient characteristics favor preserving shale gas with high gas content and production levels. [ABSTRACT FROM AUTHOR]

Abstract Mercury's low obliquity and 3:2 spin‐orbit resonance create a surface temperature distribution with large latitudinal and longitudinal variations. These propagate via thermal conduction through the thin silicate shell influencing the interior temperature distribution. We use 3‐D thermal evolution models to investigate the effects of lateral variations of surface temperature and crustal thickness on the surface and core‐mantle boundary (CMB) heat fluxes, and elastic thickness distribution. Surface temperature variations cause a long‐wavelength perturbation of the heat fluxes, as well as of the elastic lithosphere thickness, while variations in crustal thickness affect these quantities at small spatial scales. Like the surface temperature, the present‐day CMB heat flux pattern is characterized primarily by spherical harmonics of degrees two and four, which could affect dynamo generation. Placing robust constraints on the thermal evolution based on the available estimates of the age and thickness of the elastic lithosphere remains challenging due to their large uncertainties.

The thermal properties of major minerals play a key role in understanding the internal dynamic mechanism and thermal evolution of the Earth and rocky planets. In this study, we first investigated the effect of Fe on the thermal conductivity (κ) and the thermal diffusivity (D) of orthopyroxene at 1–3 GPa and 293–873 K by the transient plane source method. The κ and D both decrease with increasing temperature and decreasing pressure. With increasing Fe content, the two parameters both quickly decrease from the beginning and then slack off. We further modeled the thermal evolution of S‐type asteroids, which strongly depends on the composition model and the dimension of the planet. Combining the present data with surface heat flow and heat production, the lunar's geotherm until 1,400 km is constructed. The core‐mantle boundary temperature of the Moon is refined from 1,883 to 1,754 K. Plain Language Summary: The thermal state and the thermal evolution of rocky planets are strongly influenced by the thermal properties of the major constituent minerals. Orthopyroxene is one of such minerals for rocky planets (e.g., S‐type asteroids and moon). The Fe content can potentially affect the thermal properties of orthopyroxene. However, there are no relevant studies up to now. In this study, we systematically measured the thermal conductivity and the thermal diffusivity of pyroxene with variable Fe content at high temperature and high pressure. Our research shows that the thermal conductivity and the thermal diffusivity of orthopyroxene decrease with increasing Fe content. Adopting the results of this study, we simulate the thermal evolution of S‐type asteroids with different compositions and dimensions and construct the lunar's geotherm until the core‐mantle boundary. Key Points: Both the thermal conductivity and the thermal diffusivity of orthopyroxene decrease with temperature and increase with pressureThe thermal conductivity and the thermal diffusivity of orthopyroxene quickly decrease with iron contentThe thermal evolutions of S‐type asteroids are first simulated and the thermal structure of the lunar interior until the CMB is constrained [ABSTRACT FROM AUTHOR]

The Helanshan Mountain tectonic belt (HTB) is an intraplate deformation belt along the northwestern border of the Ordos Block in the North China Craton. When and why this intracontinental tectonic belt formed, its subsequent uplift and erosion, and the relationships between ranges and adjacent basins remain unclear. To better assess the connections between the temporal and structural activity in HTB, apatite fission-track (AFT) and zircon fission-track (ZFT) analyses were conducted in this study. The lack of adequate FT data from the HTB is a source of contention and dispute. This paper collected samples for AFT and ZFT techniques from the central and southern HTB, trying to improve the research. The ZFT and AFT ages could be divided into the following 7 groups: 279 Ma, 222–213 Ma, 193–169 Ma, 151–147 Ma, 130–109 Ma, 92–77 Ma, and 65–50 Ma. The inverse modeling results of AFT indicate 4 fast cooling episodes of 170–120 Ma, 120–95 Ma, 66–60 Ma, and ~10–8 Ma to the present. Combining the results of FT analysis with radial plot and inverse modeling of AFT, the following eight age groups are believed to reveal the distinct tectonic activities in HTB: the first age group of 279 Ma mainly represented the back-arc extension of the southern HTB; the age group of 222–213 Ma was bounded with NNE-SSE trending contraction between the South China block and North China Craton; the event of 193–169 Ma responded to the post-orogenic collapse followed after the second event; the 151–147 Ma group was interpreted as the eastward extrusion induced by the subduction between Qiangtang and Lhasa blocks; the Early Cretaceous (130–109 Ma) group was not only affected by the rollback of the Pacific Plate, but also denoted the collapse of the thickened lithosphere formed in the Late Jurassic; the Late Cretaceous (92–77 Ma) group was attributed to long-distance impact from the subduction of the Pacific Plate beneath the Eurasian Plate; the event during 65–50 Ma was a correspondence to far-field effect of the onset collision between the Eurasian and Indian Plates; and from 10–8 Ma to the present, the progressive collision of the Indian and Eurasian Plates have a significant impact on the HTB and the northeastern Tibetan Plateau. [ABSTRACT FROM AUTHOR]

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Due to global change, many species are shifting their distribution and are thereby confronted with novel thermal conditions at the moving range edges. Especially during the initial phases of exposure to a new environment, it has been hypothesized that plasticity and associated epigenetic mechanisms enable species to cope with environmental change. We tested this idea by capitalizing on the well-documented southward range expansion of the damselfly Ischnura elegans from France into Spain where the species invaded warmer regions in the 1950s in eastern Spain (old edge region) and in the 2010s in central Spain (new edge region). Using a common garden experiment at rearing temperatures matching the ancestral and invaded thermal regimes, we tested for evolutionary changes in (thermal plasticity in) larval life history and heat tolerance in these expansion zones. Through the use of de- and hypermethylating agents, we tested whether epigenetic mechanisms play a role in enabling heat tolerance during expansion. We used the phenotype of the native sister species in Spain, I. graellsii , as proxy for the locally adapted phenotype. New edge populations converged toward the phenotype of the native species through plastic thermal responses in life history and heat tolerance while old edge populations (partly) constitutively evolved a faster life history and higher heat tolerance than the core populations, thereby matching the native species. Only the heat tolerance of new edge populations increased significantly when exposed to the hypermethylating agent. This suggests that the DNA methylation machinery is more amenable to perturbation at the new edge and shows it is able to play a role in achieving a higher heat tolerance. Our results show that both (evolved) plasticity as well as associated epigenetic mechanisms are initially important when facing new thermal regimes but that their importance diminishes with time. [ABSTRACT FROM AUTHOR]

Regardless of the steady increase of computing power during the last decades, numerical models in a 3D spherical shell are only used in specific setups to investigate the thermochemical convection in planetary interiors, while 2D geometries are typically favored in most exploratory studies involving a broad range of parameters. The 2D cylindrical and the more recent 2D spherical annulus geometries are predominantly used in this context, but the extent to how well they reproduce the 3D spherical shell results in comparison to each other and in which setup has not yet been extensively investigated. Here we performed a thorough and systematic study in order to assess which 2D geometry reproduces best the 3D spherical shell. In a first set of models, we investigated the effects of the geometry on thermal convection in steady‐state setups while varying a broad range of parameters. Additional thermal evolution models of three terrestrial bodies, namely Mercury, the Moon, and Mars, which have different interior structures, were used to compare the 2D and 3D geometries. Our investigations show that the 2D spherical annulus geometry provides results closer to models in a 3D spherical shell compared to the 2D cylindrical geometry. Our study indicates where acceptable differences can be expected when using a 2D instead of a 3D geometry and where to be cautious when interpreting the results. Plain Language Summary: In geodynamic modeling, numerical models are used in order to investigate how the interior of a terrestrial planet evolves from the earliest stage, after the planetary formation, up to present day. Often, the mathematical equations that are used to model the physical processes in the interior of rocky planets are discretized and solved using geometric meshes. The most commonly applied geometries are the 3D spherical shell, the 2D cylinder, and the 2D spherical annulus. While being the most accurate and realistic, the 3D geometry is expensive in terms of computing power and time of execution. On the other hand, 2D geometries provide a reduced accuracy but are computationally faster. Here we perform an extensive comparison between 2D and 3D geometries in scenarios of increasing complexity. The 2D spherical annulus geometry shows much closer results to the 3D spherical shell when compared to the 2D cylinder and should be given preference in 2D modeling studies. Key Points: Interior dynamics models using the 2D spherical annulus geometry match the results of a 3D spherical shell better than the 2D cylinderThe difference between 2D and 3D geometries decreases when models are heated from below by the core and from within by radioactive elementsThe 2D spherical annulus shows negligible differences to 3D for the thermal evolution of Mercury and the Moon, and acceptable values for Mars [ABSTRACT FROM AUTHOR]

Abstract The thermal properties of major minerals play a key role in understanding the internal dynamic mechanism and thermal evolution of the Earth and rocky planets. In this study, we first investigated the effect of Fe on the thermal conductivity (κ) and the thermal diffusivity (D) of orthopyroxene at 1–3 GPa and 293–873 K by the transient plane source method. The κ and D both decrease with increasing temperature and decreasing pressure. With increasing Fe content, the two parameters both quickly decrease from the beginning and then slack off. We further modeled the thermal evolution of S‐type asteroids, which strongly depends on the composition model and the dimension of the planet. Combining the present data with surface heat flow and heat production, the lunar's geotherm until 1,400 km is constructed. The core‐mantle boundary temperature of the Moon is refined from 1,883 to 1,754 K.

Abstract Regardless of the steady increase of computing power during the last decades, numerical models in a 3D spherical shell are only used in specific setups to investigate the thermochemical convection in planetary interiors, while 2D geometries are typically favored in most exploratory studies involving a broad range of parameters. The 2D cylindrical and the more recent 2D spherical annulus geometries are predominantly used in this context, but the extent to how well they reproduce the 3D spherical shell results in comparison to each other and in which setup has not yet been extensively investigated. Here we performed a thorough and systematic study in order to assess which 2D geometry reproduces best the 3D spherical shell. In a first set of models, we investigated the effects of the geometry on thermal convection in steady‐state setups while varying a broad range of parameters. Additional thermal evolution models of three terrestrial bodies, namely Mercury, the Moon, and Mars, which have different interior structures, were used to compare the 2D and 3D geometries. Our investigations show that the 2D spherical annulus geometry provides results closer to models in a 3D spherical shell compared to the 2D cylindrical geometry. Our study indicates where acceptable differences can be expected when using a 2D instead of a 3D geometry and where to be cautious when interpreting the results.

Composites made from carbon and nanominerals show great potential for thermal phase change materials, environmental water treatment, and biomass conversion. In 2019, a micro and nano-quartz-carbon ore was discovered in Feng-cheng City, Jiangxi Province. The study of the structural and physicochemical changes of quartz-carbon ore (QZC) during calcination is essential for the preparation of QZC-based composites and to broaden their application areas. Firstly, the SiO2 crystal structure evolution of QZC during calcination was investigated using in-situ X-ray diffraction (XRD), 29Si magic-angle sample spinning nuclear magnetic resonance (MAS NMR), and Fourier transform infrared FTIR spectroscopy. Then, the changes in carbon during calcination were investigated using Raman spectroscopy, 13C MAS NMR, and X-ray photoelectron spectroscopy (XPS). In addition, changes in the QZC morphology were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Finally, the evolution of the physicochemical properties of QZC during calcination was revealed using thermogravimetric (TG), Brunauer–Emmet–Teller (BET), resistivity, thermal conductivity, and zeta potential techniques. [ABSTRACT FROM AUTHOR]

Low-rank coal accounts for over half of China's proven coal reserves. The possibility of coal and gas outbursts in low-rank coal is higher, especially in the m·agmatic thermal evolution area. The complexity of coal's molecular structure is one of the reasons for problems during the process of mining operations. Different analysis techniques, including XRD, FTIR and Raman spectroscopy, were used to obtain the molecular characteristics of magmatic thermal evolution coal samples and normal coal samples, so that a comparative study could be carried out to investigate the influence of the magmatic thermal evolution effect on the molecular structure of low-rank coal. The ranges of the aromatic interlayer spacing (d002), average stacking heights (Lc) and stacking layer number (Nave) of the thermally evolved coal samples are 3.41–3.51 Å, 22.76–27.02 Å, and 6.68–7.70, respectively. The ranges of the full width at half maximum ratio (FD1/FG) and the peak integral intensity ratio (ID1/IG) are 2.16–2.19 and 1.55–1.84, respectively. Compared with the normal coal samples, those affected by magmatic thermal evolution have smaller d002, ID1/IG, and FD1/FG values, but larger Lc values. The results indicate that the thermally evolved coal samples have more ordered structures and more developed microcrystalline structure sizes than normal coal samples. [ABSTRACT FROM AUTHOR]

In the current work, we report on the synthesizing of a series of novel nanocomposite materials obtained by functionalizing the SBA-15 silica matrix with anchored iron phosphonate molecules and the following thermal treatment. The obtained results reveal the formation of a unique amorphic layer of Fe-based compounds on the surface of silica walls of SBA-15 channels as a result of the organic groups' decomposition after moderate thermal treatment. Due to their unique structure, represented in an active Fe-containing amorphous coating spread over a large surface area, these materials are of great interest for their potential applications in fields such as catalysis, adsorption, and non-linear optics. The obtained materials remain amorphous, preserving the SBA-15 mesoporous structure up to temperatures of approximately 800 °C, after which the partial melting of the silica backbone is observed with the simultaneous formation of nanocrystals inside the newly-formed glassy mass. All obtained materials were characterized using such techniques as thermogravimetry, transmission and scanning electron microscopy combined with energy dispersive x-ray spectroscopy mapping, Raman spectroscopy, N2 sorption analysis, x-ray diffraction, x-ray photoelectron spectroscopy, Mössbauer spectroscopy, and SQUID measurements. [ABSTRACT FROM AUTHOR]

The thermal state of the early Earth's interior and its way of cooling are crucial for its subsequent evolution. Earth is initially hot as it acquired enormous heat in response to violent processes during its formation, e.g., the Moon-forming giant impact, the segregation and formation of its metallic core, the tidal interaction with the early Moon, and the decay of radioactive elements, etc. In the meantime, the cooling mechanisms of early Earth's mantle remain elusive despite their importance, and the previously proposed cooling models of the mantle are controversial. In this paper, we first reviewed several prevalent parameterized thermal evolution models of the early mantle. The models give unrealistic predictions since they were established solely based on a single tectonic regime, such as the stagnant-lid regime, or relied on the disputable existence of the plate tectonics prior to ~ 3.5 Ga. Then we argue that the mantle should have started to cool down from a very hot state after the solidification of the ferocious magma ocean. Instead of using one single scaling law to describe a single-stage model, we suggest that an episodic multi-stage cooling model (EMCM) of the early mantle could be more plausible to account for the mantle's early cooling process. The model reconciles with the fact that the mantle cools down from a hot state prior to ~ 3.5 Ga and can also explain the well-constrained post-3.5 Ga thermal history of the mantle. [ABSTRACT FROM AUTHOR]

In this study, galeite, Na15(SO4)5ClF4 and schairerite, Na21(SO4)7ClF6 were investigated via in situ single-crystal X-ray diffraction in the temperature range of 300–750 K. Galeite and schairerite are trigonal, P31m, a = 12.1903(2), c = 13.9454(2) Å, V = 1794.69(6) Å3, and Z = 3 (R1 = 0.0273, 300 K) for galeite and a = 12.1859(3), c = 19.3080(6) Å, V = 2483.04(14) Å3, and Z = 3 (R1 = 0.0334, 300 K) for schairerite. The crystal structures of galeite and schairerite are based upon frameworks consisting of alternating face- and corner-sharing fluorine- and chlorine-centered octahedra. Galeite and schairerite can be attributed to 5H (galeite) and 7H (schairerite) antiperovskite polytypes, respectively. It was observed that schairerite undergoes at least one reversible phase transition before it starts to lose its crystallinity at 750 K. This phase transition occurs in the temperature range of 550–600 K. The high-temperature modification of schairerite is trigonal, with the centrosymmetric space group P-3m1 and the unit-cell parameters a = 7.0714(2), c = 19.5972(7) Å, V = 848.66(6) Å3, and Z = 1. Galeite is stable up to 600 K. The crystal structures of minerals expand anisotropically, and, in both cases, the strongest thermal expansion was parallel to the modules of face-sharing anion-centered octahedra. The structural complexity analysis showed that galeite is complex (695.175 bits/cell) and that the LT-modification of schairerite is very complex (1064.990 bits/cell), whereas its HT-modification is intermediate in complexity (256.755 bits/cell). The complexities of LT- and HT-polymorphs of schairerite are consistent with the general observations regarding structures with positional disorder: complexity decreases with increasing temperature, and simpler polymorphs have lower physical density. [ABSTRACT FROM AUTHOR]

The purpose of this work is to produce a family of equations describing the evolution of the temperature in a rigid heat conductor. This is obtained by means of successive approximations of the Fourier law, via memory relaxations and integral perturbations. [ABSTRACT FROM AUTHOR]

Abstract Nanometer scaled pores are critical to studying gas shale reservoirs. In order to obtain the information of the evolution mechanism of nanoscale pore within lacustrine organic-rich shales, artificially matured shale samples from the Ordos Basin were treated using hydrous pyrolysis experiment. Low-temperature nitrogen adsorption, inductively coupled plasma atomic emission spectrometry (ICP-AES), and field emission scanning electron microscopy (FE-SEM) experiments were used to investigate the nanopore evolution with migration and precipitation of materials. The results show that the pore sizes were distributed from 1.1 to 500 nm, and the overall porosity tends to increase first and then decrease. The micropores and fine mesopores (

The Helanshan Mountain tectonic belt (HTB) is an intraplate deformation belt along the northwestern border of the Ordos Block in the North China Craton. When and why this intracontinental tectonic belt formed, its subsequent uplift and erosion, and the relationships between ranges and adjacent basins remain unclear. To better assess the connections between the temporal and structural activity in HTB, apatite fission-track (AFT) and zircon fission-track (ZFT) analyses were conducted in this study. The lack of adequate FT data from the HTB is a source of contention and dispute. This paper collected samples for AFT and ZFT techniques from the central and southern HTB, trying to improve the research. The ZFT and AFT ages could be divided into the following 7 groups: 279 Ma, 222–213 Ma, 193–169 Ma, 151–147 Ma, 130–109 Ma, 92–77 Ma, and 65–50 Ma. The inverse modeling results of AFT indicate 4 fast cooling episodes of 170–120 Ma, 120–95 Ma, 66–60 Ma, and ~10–8 Ma to the present. Combining the results of FT analysis with radial plot and inverse modeling of AFT, the following eight age groups are believed to reveal the distinct tectonic activities in HTB: the first age group of 279 Ma mainly represented the back-arc extension of the southern HTB; the age group of 222–213 Ma was bounded with NNE-SSE trending contraction between the South China block and North China Craton; the event of 193–169 Ma responded to the post-orogenic collapse followed after the second event; the 151–147 Ma group was interpreted as the eastward extrusion induced by the subduction between Qiangtang and Lhasa blocks; the Early Cretaceous (130–109 Ma) group was not only affected by the rollback of the Pacific Plate, but also denoted the collapse of the thickened lithosphere formed in the Late Jurassic; the Late Cretaceous (92–77 Ma) group was attributed to long-distance impact from the subduction of the Pacific Plate beneath the Eurasian Plate; the event during 65–50 Ma was a correspondence to far-field effect of the onset collision between the Eurasian and Indian Plates; and from 10–8 Ma to the present, the progressive collision of the Indian and Eurasian Plates have a significant impact on the HTB and the northeastern Tibetan Plateau.

Nanometer scaled pores are critical to studying gas shale reservoirs. In order to obtain the information of the evolution mechanism of nanoscale pore within lacustrine organic-rich shales, artificially matured shale samples from the Ordos Basin were treated using hydrous pyrolysis experiment. Low-temperature nitrogen adsorption, inductively coupled plasma atomic emission spectrometry (ICP-AES), and field emission scanning electron microscopy (FE-SEM) experiments were used to investigate the nanopore evolution with migration and precipitation of materials. The results show that the pore sizes were distributed from 1.1 to 500 nm, and the overall porosity tends to increase first and then decrease. The micropores and fine mesopores (< 10 nm) increased gradually from the 250 to the 350 °C, calcite appeared dissolution following a small peak of feldspar dissolution at this stage, and the CO2 reaches a partial pressure peak at 350 °C. The micropores, mesopores and macropores increased steeply from the 370 °C to the 450 °C. Organic pores were not developed until 350 °C, and well developed at 370 and 400 °C. Organic pores, intergranular pores of clay and intragranular pores of pyrite were well developed at 370 °C. The cumulative specific surface areas increased at 400 °C caused by the dehydration and transformation reaction of clay minerals. This study could provide a reference for the exploration of shale gas in lacustrine shales with different thermal maturities. [ABSTRACT FROM AUTHOR]

The Dongying Depression (Bohai Bay Basin, eastern China) was widely filled with evaporite (anhydrite and halite) layers during the Paleogene period, especially the middle of the fourth member of the Shahejie Formation (Es4). Most evaporite layers are interbedded with mudstone strata. The strata of Es4 are divided into three sections, referred to as the upper layers, evaporite layers, and lower layers, respectively. The analysis of elemental concentrations, elemental ratios, and Pr/Ph suggests that the lower layers were deposited in an intermittent saline lake environment within a relatively dry climate. The evaporite layers were formed in a highly saline lake environment, whereas the upper layers were formed in a brackish-saline to fresh-water environment. Organic matter (OM) abundance indices, including total organic carbon (TOC), chloroform extracts, total hydrocarbon content (HC), hydrocarbon generation potential (S1 + S2), and OM type, show that the source rock potential for petroleum generation in the upper layers is best, that in the evaporite layers is fair, and in the lower layers it is poor. Carbon isotopes (δ13C) of hydrocarbons in the evaporite and lower layers were heavier than those in the upper layers. Thermal maturity parameters show that the thermal evolution process of OM in the upper layers was faster where evaporite were present compared with evaporite-free areas, while the thermal evolution of OM in the lower layers was slower in these regions. The high thermal conductivity of evaporites may have accelerated the thermal evolution of source rocks in upper layers and allowed hydrocarbon generation at a shallower burial depth. This resulted in the earlier appearance of the petroleum generation window compared to in evaporite-free areas. Meanwhile, the thermal evolution of OM in the lower layers was restrained, and consequently the hydrocarbon generation window was widened, which implies the potential for petroleum exploration in deep strata under the evaporite sequence. This is a common phenomenon in evaporite-bearing basins, according to previous and present studies. [ABSTRACT FROM AUTHOR]

The continental shale oil in the second member of Paleogene Funing Formation in the Qintong Sag, Subei Basin has the characteristics of high and stable production. Based on the analysis of the formation conditions of shale oil, the genesis of shale oil is revealed according to crude oil geochemical characteristics and physical properties. Results show that the mud shale in the second member of Funing Formation in the Qintong Sag is widely distributed and thick, with medium organic matter abundance and moderate thermal evolution, which provides a good material basis for the formation of shale oil. The shale oil in the second member of Funing Formation has the characteristics of low gas/oil ratio and high pressure, which belongs to low sulfur and light to medium oil, with high content of saturated hydrocarbon and light hydrocarbon, and the associated gas of crude oil is mainly methane. The shale oil has high content of β-daucane and gammacerane, and its sterane content of ααα-C29 (20R) is higher than that of ααα-C27 (20R), indicating that it is formed in the reduction environment of salt water. Thermal evolution is the key factor controlling the quality of continental shale oil. The second member of Funing Formation in the deep sag zone is at the peak of hydrocarbon generation, and the shale oil has good fluidity. The mud shale in the Ⅰ and Ⅱ submembers of the second member of Funing Formation generally contains suberinite (6.6%) and amorphous body of benthic algal (11.5%), and can generate oil and gas at the mature stage, which is conducive to the formation of light components. The mud shale in the second member of Funing Formation has the characteristics of moderate organic matter abundance and mineral composition, and its oil adsorption capacity is poor, making the remaining oil mainly free oil (69%-96%).

The most accurate measurements of the mass attenuation coefficient for metals at low temperature for the zinc K-edge from 9.5 keV to 11.5 keV at temperatures of 10 K, 50 K, 100 K and 150 K using the hybrid technique are reported. This is the first time transition metal X-ray absorption fine structure (XAFS) has been studied using the hybrid technique and at low temperatures. This is also the first hybrid-like experiment at the Australian Synchrotron. The measured transmission and fluorescence XAFS spectra are compared and benchmarked against each other with detailed systematic analyses. A recent method for modelling self-absorption in fluorescence has been adapted and applied to a solid sample. The XAFS spectra are analysed using eFEFFIT to provide a robust measurement of the evolution of nanostructure, including such properties as net thermal expansion and mean-square relative displacement. This work investigates crystal dynamics, nanostructural evolution and the results of using the Debye and Einstein models to determine atomic positions. Accuracies achieved, when compared with the literature, exceed those achieved by both relative and differential XAFS, and represent a state-of-the-art for future structural investigations. Bond length uncertainties are of the order of 20–40 fm.

According to the latest three-dimensional seismic stratification data, the Triassic source rocks are recognized to be deeply buried on the southern slope of Kuqa Depression, Tarim Basin, making it possible to develop local source rocks. Based on geochemical data and basin simulation, the burial history, thermal history and maturity evolution history of Triassic source rocks in this area were simulated and analyzed. By discussing the thermal evolution and maturity process of source rocks, the maturity stage and hydrocarbon generation stage of source rocks were proposed and their reservoir forming significance was further discussed. The source rocks of the Triassic Karamay Formation are distributed on the southern slope of Kuqa Depression. The burial depth in the southern area of Xinhe is generally about 6 700 m, which tends gradually to deepen in the north and reaches themaximum depth over 8 000 m, showing an overall characteristics of "shallowly buried in the south and deeply buried in the north". The southern slope of Kuqa Depression has the same overall subsidence amplitude, which has experienced the tectonic evolution process of stable burial in the early stage, continuous subsidence in the middle stage and rapid burial in the late stage. During the Triassic period, the strata were deposited stably and the burial depth was small. From Cretaceous to Paleogene, continental clastic rocks were mainly deposited, and the strata continued to deposit. From Neogene to present, the southern slope of Kuqa Depression entered the stage of rapid thermal subsidence, and the burial depth reached the largest. The evolution degree of Triassic source rocks on the southern slope of Kuqa Depression is characterized by "high degree in the north and low degree in the south". The northern region matured early, which entered the hydrocarbon generation threshold at the beginning of Paleogene (Ro=0.5%), evolved to mature stage by the end of Paleogene (Ro=0.7%) and to high maturity stage in the middle Neogene (Ro=1.0%) and till now (Ro=1.30%), mainly generating gas. The southern region matured relatively late, which entered the oil window in the early Neogene, reached mature stage in the middle Neogene (Ro=0.7%), and till now (Ro=0.86%), mainly generating oil. There are two oil and gas transportation of far-source and near-source on the southern slope of Kuqa Depression, which provides sufficient sources for oil and gas accumulation. This area has the overall characteristics of dual source hydrocarbon supply.

The first results of laser ablation inductively-coupled plasma mass-spectrometry apatite fission-track dating are presented from drill core of boreholes, which exposed the top of the Siberian Platform's crystalline basement in the Nepa–Botuoba Anteclise. Apatite fission-track ages, obtained for nine samples from a depth of ~2 km, form three groups with mean values of 200, 140, and 60 Ma. A thermal event with an age of ~200 Ma is widely abundant almost within the entire Siberian Platform and reflects the stage of its intense Early Jurassic uplifting. Resetting of the apatite fission-track system ~140 Ma corresponds to tectono-thermal events, which mark the final stage of collision of the Mongol–Okhotsk fold belt. The youngest apatite fission-track ages age of ~60 Ma, on the one hand, may reflect the beginning of the Baikal rifting and, on the other hand, may be a result of the high U content of apatite. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northeast Petroleum University is the property of Journal of Northeast Petroleum University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The vigor of the thermal convection in a terrestrial magma ocean tends to prevent the sedimentation of the solid grains. Understanding of the overall dynamical behavior of this solid phase segregation is required to anticipate the solidification mechanisms in the early Earth mantle. We develop numerical models to monitor the crystal fraction evolution of a convecting magmatic reservoir. Our models show that the ability of the crystal fraction to disperse or sediment within the domain strongly depends on the crystal size, the density difference and the magma viscosity. Our models show that the critical value of the convection/buoyancy stress ratio separating sedimentation/suspension regimes can be smaller than 0.1. Hence, during the early crystallization of a magma ocean, suspension should be the dominant process. We then investigate the possibility of bridgmanite segregation by comparing the density difference between the MO and the solid crystals for different compositions and the critical density contrast above which crystal segregation is likely to occur. We define the relevant set of parameters; including the P‐V‐T equations of state of coexisting melt and bridgmanite in the mushy MO. We observe that bridgmanite grains are unlikely to segregate in a mantle of pyrolite composition. However, bridgmanite segregation is more likely to occur at the bottom of a MO enriched in SiO2, compared to pyrolite. When a solidifying layer contains 60% of bridgmanite and 40% of melt, we observe a significant SiO2 enrichment with increasing mantle depth in a primitive mantle compatible with seismic and geochemical observations. Plain Language Summary: Following the giant impact that formed the Earth‐Moon system, the Earth's mantle probably underwent a major melting episode forming a magma ocean several hundred kilometers thick. During the solidification of this magma ocean, the first crystals either settled at depth or were efficiently mixed with the magma. This process played a determining role in the chemical composition of the early mantle. We have developed numerical models to monitor the evolution of a thin layer of crystals in a magma ocean. Our models characterize the influence of crystal size, magma viscosity and density difference between crystals and magma. Our models support efficient mixing of crystals in the magma ocean. However, in some settings such as a SiO2‐rich magma ocean, bridgmanite grains may separate from the magma and form a solid layer at the base of the Earth's mantle early during cooling. This process may generate SiO2 enrichment with depth in agreement with seismic and geochemical observations. Key Points: We develop numerical models to monitor the crystal fraction evolution within a convecting magma oceanWe illustrate that during the early crystallization of a magma ocean, suspension should be the dominant process compared to sedimentationWe observe that bridgmanite segregation is more likely to occur at the bottom of a MO enriched in SiO2 compared to pyrolite [ABSTRACT FROM AUTHOR]

With the comparable sedimentary organic phase, the relative abundance of rearranged hopanes can be correlated to maturity degree. By the approach of artificial maturation experiments of low-maturity (Ro=0.58%) and organic-rich (TOC=3.87%) mud shale collected from the Ordos Basin, 17α(H)-diahopanes in expelled and retained oils were examined by gas chromatography-mass spectrometry (GC-MS). The thermal evolution characteristics of parameters related to 17α(H)-diahopane were discussed, and the maturity range of these parameters as maturity indicators was proposed, combined with the random mean vitrinite reflectance (Ro) of maturated rock samples of each step of pyrolysis. Results show that the parameters of C29*/(C29*+C29H) and C30*/(C30*+C30H) have similar three-stage variations. As experimental temperature increased, the values of the two parameters decreased firstly, then increased and finally decreased again, indicating that they may be good indicators for oil-source correlation. Before 325 ℃, i.e. Ro < 1.01%, both parameters showed insignificant changes. However, they both showed an obvious upward trend with increasing temperature from 325 to 385 ℃, indicating that they were valid indicators for maturity from the moderate to the early stages of high maturity (i.e. 1.01% < Ro < 1.48%).

The southern Sichuan Basin in China holds abundant shale gas resources; however, the shale gas bearing property shows great differences due to the multiple stages of tectonic transformation. The key to revealing the shale gas differential enrichment mechanism is to explore the thermal evolution characteristics during tectonic evolution. Therefore, taking the Luzhou and Changning blocks as an example, which have obvious differences in tectonic evolution, the organic geochemical conditions of Longmaxi shale were firstly compared with the test data. Then, the thermal evolution characteristics under the background differential tectonic uplift-erosion were recovered using basin modeling techniques. The results showed that the two blocks contain similar organic geochemical conditions of the Longmaxi shale. Moreover, the hydrocarbon generation condition in Luzhou Block is greater than that in the Changning Block. Influenced by the differential tectonic evolution, the study area experienced a complex burial history and the formation of multiple unconformities. As a result, the present burial depth of Longmaxi Formation in the Luzhou Block is significantly greater than that in the Changning Block. The thermal evolution history of Longmaxi shale in the study area could be divided into three stages, including a low-temperature stage from Caledonian to Hercynian, a middle-temperature stage from Hercynian to Indosinian, and a high-temperature stage from Yanshanian to Himalayan. In addition, it was found that the Himalayan period is the main stage resulting in the differential gas bearing property of Longmaxi shale in the southern Sichuan area. Under the differential structural modification, the peak time of hydrocarbon generation in the Luzhou Block occurred earlier and the conversion rate was slightly higher than that in the Changning Block. [ABSTRACT FROM AUTHOR]

Preventing the thermal damage of diamond abrasives is the major challenge of diamond composites in the field of super-hard tools by laser additive manufacturing. In the presented work, we established a quantitative framework to accurately evaluate the thermal damage behaviour and the relevant microstructure-performance characteristics, by using CuSn10-diamond composite by powder bed fusion-laser beam (PBF-LB). By simulating the thermal history of diamond in the molten pool and microstructure characterisation, the critical temperature of 1491.6°C of diamond graphitisation was obtained. Below the critical temperature, the composite with no diamond-graphitisation exhibited abrasive wear and wear loss rate below 0.01%. The increasing temperature led to the aggravation of graphitisation, which ID: IG value changed from 2.00 to 0.57 with the temperature increasing from 1491.6°C to 1896.1°C, resulting in wear mechanism changing from adhesive wear to three-body abrasion, with the wear loss rate from 0.01% to 0.73%. Integrating the results of simulation, microstructures and wear properties, the graphitisation threshold of diamond in PBF-LB was revealed and the quantitative relationship of 'PBF-LB parameters - Temperature - Graphitisation degree - Wear resistance' of the metal-matrix diamond composites was established. [ABSTRACT FROM AUTHOR]

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The most accurate measurements of the mass attenuation coefficient for metals at low temperature for the zinc K-edge from 9.5 keV to 11.5 keV at temperatures of 10 K, 50 K, 100 K and 150 K using the hybrid technique are reported. This is the first time transition metal X-ray absorption fine structure (XAFS) has been studied using the hybrid technique and at low temperatures. This is also the first hybrid-like experiment at the Australian Synchrotron. The measured transmission and fluorescence XAFS spectra are compared and benchmarked against each other with detailed systematic analyses. A recent method for modelling self-absorption in fluorescence has been adapted and applied to a solid sample. The XAFS spectra are analysed using eFEFFIT to provide a robust measurement of the evolution of nanostructure, including such properties as net thermal expansion and mean-square relative displacement. This work investigates crystal dynamics, nanostructural evolution and the results of using the Debye and Einstein models to determine atomic positions. Accuracies achieved, when compared with the literature, exceed those achieved by both relative and differential XAFS, and represent a state-of-the-art for future structural investigations. Bond length uncertainties are of the order of 20-40 fm. [ABSTRACT FROM AUTHOR]

The "new core paradox" suggests that the persistence of the geomagnetic field over nearly all of Earth history is in conflict with the core being highly thermally conductive, which makes convection and dynamo action in the core much harder prior to the nucleation of the inner core. Here we revisit this issue by exploring the influence of six important parameters on core evolution: upper/lower mantle viscosity ratio, core thermal conductivity, core radiogenic heat rate, mantle radiogenic heating rate, central core melting temperature, and initial core‐mantle boundary (CMB) temperature. Each parameter is systematically explored by the model, which couples mantle energy and core energy‐entropy evolution. A model is "successful" if the correct present‐day inner core size is achieved and the dynamo remains alive, as implied by the paleomagnetic record. In agreement with previous studies, we do not find successful thermal evolutions using nominal parameters, which includes a core thermal conductivity of 70 Wm−1K−1, zero core radioactivity, and an initial CMB temperature of 5,000 K. The dynamo can be kept alive by assuming an unrealistically low thermal conductivity of 20 Wm−1K−1 or an unrealistically high core radioactive heat flow of 3 TW at present‐day, which are considered "unsuccessful" models. We identify a third scenario to keep the dynamo alive by assuming a hot initial CMB temperature of ∼6,000 K and a central core liquidus of ∼5,550 K. These temperatures are on the extreme end of typical estimates, but should not be ruled out and deserve further scrutiny. Plain Language Summary: The cooling of Earth over geological time is of interest to many scientific disciplines and has been studied intensively. Maintaining the geomagnetic field requires continuous core cooling to drive fluid motion in Earth's liquid iron outer core. Recent studies have shown that the materials that make up Earth's core can conduct heat very efficiently, which makes fluid motion in the core more difficult. In this study we investigate the thermal and magnetic evolution of Earth using a core‐mantle cooling model. In particular, we investigate how several important aspects of Earth's interior that control its thermal and magnetic evolution over 4.5 billion years. In agreement with previous studies, we confirm that typical models fail to reproduce the thermal and magnetic evolution found in the geological record. We identify a potentially new solution that invokes (a) that the core is initially super hot following the formation of the Earth, and (b) that the melting temperature of the core material is lower than most estimates. This potential solution should be investigated further by studying the initial core temperature following planet formation and careful measurement of the melting temperatures of iron alloys. Key Points: Using nominal thermal evolution parameters the geodynamo is predicted to die prior to inner core nucleationKeeping it alive requires either a low thermal conductivity (20 W/m/K), a high core radioactivity (3 TW), or a hot initial core (6,000 K)A relatively low core melting temperature of 5,300 K correlates with higher ohmic dissipation prior to inner core nucleation [ABSTRACT FROM AUTHOR]

The high corrosion resistance, low density, and useful biological activity with heat resistance of titanium alloys have made them the most outstanding choice in various industrial applications. However, their poor tribological properties inhibit utilizing them in applications that need abrasive and adhesive wear resistance. Laser cladding is being applied to increase the capabilities of such alloys by allowing the deposition of different hard coating materials. This paper attempts to study the thermal, microstructure, and clad layer geometry evolution during coaxial laser cladding of Ti6Al4V titanium alloy with tungsten carbide + nickel-based alloy preblended powder. Owing to the difficulty in experimentally measuring the thermal and microstructure evolution due to lots of laser processing parameters, a new three-dimensional numerical model based on finite-difference analysis for studying the entire process has been proposed. The behavior of the different thermophysical properties of WC, NiCrBSiC, and Ti6Al4V materials, as well as the phase transition based on latent heat and fluid dynamics considering materials velocity, viscosity, and buoyancy force, during melting and resolidification processes, were considered to improve and ensure the accuracy of the numerical model. The proposed model could be applied to accurately estimate the temperature history and the deposited clad layer morphology and geometry. The cooling rate and thermal gradient were investigated to predict the solidification rate and microstructure by using different laser cladding parameters. It was confirmed that the laser power has a substantial impact on the peak temperature in the melt-pool, while the laser scanning speed has a significant effect on the heating and cooling rates. In conclusion, the process parameters have to be carefully chosen to certify a good quality clad layer with the preservation of the WC particles.

Accreting in the first few million years (Ma) of the Solar System, planetesimals record conditions in the protoplanetary disc and are the remnants of planetary formation processes. The meteorite paleomagnetic record carries key insights into the thermal history of planetesimals and their extent of differentiation. The current paradigm splits the meteorite paleomagnetic record into three magnetic field generation epochs: an early nebula field (≲5 Ma after CAI formation), followed by thermal dynamos (∼5–34 Ma after CAI formation), then a gap in dynamo generation, before the onset of core solidification and compositional dynamos. These epochs have been defined using current thermal evolution and dynamo generation models of planetesimals. Here, we demonstrate these epochs are not as distinct as previously thought based on refined thermal evolution models that include more realistic parametrisations for mantle convection, non-eutectic core solidification, and radiogenic 60Fe in the core. We find thermal dynamos can start earlier and last longer. Inclusion of appreciable 60Fe in the core brings forward the onset of dynamo generation to ∼1–2 Ma after CAI formation, which overlaps with the existence of the nebula field. The second epoch of dynamo generation begins prior to the onset of core solidification this epoch is not purely compositionally driven. Planetesimal radius is the dominant control on the strength and duration of dynamo generation, and the choice of reference viscosity can widen the gap between epochs of dynamo generation from 0–200 Ma. Overall, variations in planetesimal properties lead to more variable timings of different planetesimal magnetic field generation mechanisms than previously thought. This alters the information we can glean from the meteorite paleomagnetic record about the early Solar System. Evidence for the nebula field requires more careful interpretation, and late paleomagnetic remanences, for example in the pallasites, may not be evidence for planetesimal core solidification. • Planetesimal thermal dynamos can begin before the dissipation of the nebula field. • Core solidification is not required to trigger a second epoch of dynamo generation. • Planetesimal dynamos can last several 100 Ma longer than previously thought. • Planetesimal radius and reference viscosity have a strong effect on dynamo duration. [ABSTRACT FROM AUTHOR]