Microbes are known to show a great spatiotemporal distribution, and exert extensive and intensive geological agents in both modern days and Earth history. These features make the microbes play important roles on great changes of Earth environments, enabling important and wide applications in geoengineering including the pollutant remediation, decrease of atmospheric CO₂, geohazards prevention, as well as toxicity decrease. This necessitates the cross-disciplinary construction from microbial Earth to microbial geoengineering.It is well known that microbes, the engineer of elemental geochemical cycles, have played the key roles in the geoengineering fields including carbon sink, ecological remediation and the agriculture practice. The carbon pump and the microbial carbon pump, the important mechanisms to transport the atmospheric CO₂ into the sediments or seawater, are documented to mainly regulate by the microbial communities either in the sea or on the land. Microbes are widely involved into, and known as the engineer of, the geochemical cycles of greenhouse gases including CH₄, CO₂ and N₂O. These microbial processes could be exploited in the geoengineering to promote the carbon sink or decrease the carbon release. Microbial transformation of a series of metal ions as well as the degradation on organics has been widely used in the ecological remediation of polluted environments. Microbial release of elements including carbon, nitrogen, phosphor etc., from a variety of minerals is applied in agriculture practice. The artificial microbial mixtures on the basis of natural communities could be used as the nature-based fertilizers in the farming practice. Microbial roles, played on the precipitation and erosion of minerals, could also be applied into rocks and soils engineering, deep Earth engineering and mining industry. The microbial application to these geoengineerings will greatly save the costs, remarkably promote efficiency and noticeably protect the natural environments. Microbial transformation of the expansive clay minerals into no-expansive ones could be applied into the oil recovery by water flooding as well as the rocks and soils geotechnical engineering. Carbonate factory is known to be primarily induced by microbial communities via the precipitation of calcium carbonate from the fluids which could be introduced into the building of artificial islands in the sea, the filling and repairing of rock cracks, cementation of coarse grains in a variety of geoengineering. Microbial erosion of minerals could be exploited into the mining industry via the release of metals of economic significance from ores. The presence of the so-called deep biosphere, featured by the dominance of extreme environment microbes, will exert positive and negative effects on the underground storage of dangerous materials including the nuclear wastes, CO₂ and hydrogen gas. The investigations on the microbial roles on these materials as well as the storage containers are of in particular importance.Whilst most microbial geoengineering has been conducted to prevent and control the geohazards that have come into being in natural environments, microbes could further provide the early warning of some geohazards including the biotic or ecological crisis, climatic and environmental disasters, as well as landslides due to their sensitive response to minor environmental changes. To construct the early warning geoengineering via the on-site filed observatory network is of importance so that we could take some measures to prevent the occurrence of the geohazards, or make the positive use of the microbial roles but suppress the negative roles.

Heavy metal migration and enrichment in areas affected by mining and smelting cause severe soil contamination. A thorough understanding of the sources and migration of heavy metals in the soil is the scientific basis for the efficient treatment of soil pollution. In recent years, metal stable isotopes have shown great advantages in identifying sources of soil heavy metal contamination and analyzing heavy metal migration processes, thus acting as powerful tools to trace the environmental behavior of heavy metals. In this paper, we reviewed the analysis technology, tracing principles, and tracing models of metal stable isotopes, determined the isotope fractionations caused by mineral mining and smelting processes (high-temperature smelting, electrochemical processes, and tailing weathering), and discussed the representative applications of metal stable isotopes in the traceability of soil pollution in mining- and smelting-affected areas. The V isotope system is in the initial stages of investigation, and its applications in heavy metal soil source analysis are relatively lacking. Zn, Cd, and Hg isotopes are advantageous for identifying heavy metal contamination sources associated with high-temperature smelting processes. Cu, Tl, and Ni isotopes can directly indicate the ore content of the soil. However, some problems remain, such as the difficulty in analyzing certain systems of metallic stable isotopes, limitations in the application of tracer models, and source uncertainties due to isotope fractionation. Therefore, in the future, it will be necessary to further explore and optimize metal isotope analysis methods, establish more metal stable isotope fingerprints, develop traceability models with stronger applicability and more accurate results, comprehend the characteristics and mechanisms of isotope fractionation in complex interfacial processes and reactions, and strengthen the practical application of metal stable isotopes to trace the history of soil heavy metal pollution.

Cretaceous Oceanic Anoxic Events (OAEs) have recorded significant changes in the climatic and paleoceanographic states of the planet and represent major carbon cycle perturbations. In the past two decades, analytical techniques for stable metal isotopes, such as molybdenum, zinc, uranium, chromium, cadmium, and calcium isotopes, have been developed to study OAEs. By systematically summarizing the geochemical characteristics of molybdenum isotopes (δ⁹⁸Mo), zinc isotopes (δ⁶⁶Zn), and uranium isotopes (δ²³⁸U), and research advances on Cretaceous OAEs, we found that molybdenum isotopes mainly reflect the transformation between sulfide and non-sulfide in the regional marine environment during OAEs. Zinc isotopes can reflect different responses of regional marine environments to different processes, such as primary productivity, continental weathering, and sediment burial/decomposition. Uranium isotopes can be used to estimate the global extent of seafloor euxinia. The coupled global C-P-U cycle model can simulate the response mechanism of the global ocean to different processes, such as the formation of large igneous provinces, continental weathering, and biological activities. However, the cyclic fractionation mechanism of these isotopes in marine systems is still in progress, and most research has only focused on the deposition record of OAE2. In the future, it will be necessary to conduct more systematic research on OAEs.

Water stable isotopes （δ） are inherent in the water cycle， changing during water phase changes， and hence widely used to study moisture trajectory and water cycle. Their application to the study of atmospheric circulations over the Tibetan Plateau （TP） has led to a comprehensive understanding in the past decades. This review focuses on field sampling across the extensive TP， and summarizes the spatial and temporal variation patterns in water stable isotopes in precipitation， surface water and ice cores. Complex circulation patterns are found to affect the altitude effect in water stable isotopes， so that monsoon yields a smaller altitudinal lapse rate than westerly， which in extreme cases can result in increasing isotopic composition with increasing altitudes； though the precipitation isotopes have a prevailing dominance over surface water isotopic features. The sensitive response of precipitation stable isotopes to convection is also applied to the judgement of monsoon onset based on abrupt， continuous and significant decrease in δ. Accordingly， the submonsoon system is found to onset earlier over the Bay of Bengal than the South China Sea and varies diversely under global warming. A long-term perspective into atmospheric circulation over the Tibetan Plateau from ice core δ reveals significant impacts of El Nin?o-Southern Oscillation （ENSO） on the TP， with a dampening effect on the temperature significance of ice core isotopes in the southern TP under the monsoon dominance， while a lagged correlation between ENSO and ice core isotopes in the northwestern TP； all pointing to possible teleconnections between TP climates and sea surface temperature. In future studies， the Earth system models will be relied upon to help reveal physical mechanisms behind complex water stable isotope variations， and comprehend unique isotope variation patterns under extreme climates. Based on modern precipitation δ variation features and abrupt changes and triggering mechanisms， variation history of moisture sources is to be reconstructed from paleoproxies. Besides， isotopic parameters including deuterium excesses have high meteorological synoptic capacity， and would be applied to the analysis of changes in sea surface temperature or evaporation， and hence to facilitate the understanding of sea-air interactions， and the interactions of circulation patterns and water cycles on the Tibetan Plateau with global climate changes.

Research on the tectonic and thermal evolution of coal measures' source rocks is of great significance for revealing the generation mechanism of coal-measures gas. To reveal the process of tectonic-thermal evolution， the stage of hydrocarbon generation and expulsion， and the genetic types of the coal-measure gas， the thermal and hydrocarbon generation evolution histories of the source rocks in the Mesozoic coal measures in the Huangling mining area were studied in this paper， based on the data of lithology， buried depth， porosity， maximum vitrinite reflectance， carbon and hydrogen isotopic compositions of methane and biogas yield and with the use of the methods of Petromod 1D simulation， back-stripping inversion， and EASY% R_O. The results show that the Mesozoic coal measures experience thrice-quartic "subsidence-uplift" stages in the Huangling mining area since the beginning sedimentation at the Late Triassic. The hydrocarbon generation process can be divided into three phases. The first stage is the primary biogas generation period during the Late Triassic to the early middle Jurassic. The maximum vitrinite reflectance evolved to 0.3%. In the second period of thermogenic gas generation during the early Middle Jurassic to late Early Cretaceous， the burial depth and thermal temperature of the coal measures continuously increased to the highest level at the end of the Early Cretaceous. The maximum vitrinite reflectance evolved to 0.67%~ 0.74%. In the third period of secondary biogas generation during Early Eocene so far， the coal measures' burial depth is uplifted to 2 077~2 148 m， and the thermal temperature is decreased to less than 75 ℃. The data of the carbon and hydrogen isotopic composition of methane and the accumulatively generated methane amount of 10.5~16.1 μmol/g during the experiment of microbial degradation No. 2 and No. 3 coal provide evidence for the occurrence of secondary biogenic gas in the Huangling mining area.