Under the global decarbonization initiative, natural hydrogen has garnered significant attention as a green, high-calorific-value, zero-carbon emission clean energy source in marine and continental contexts. Previous research on natural hydrogen systems remains nascent. This study systematically synthesized the distribution characteristics, genetic mechanisms, and enrichment processes of high-concentration natural hydrogen globally, yielding four key insights: (1) Natural hydrogen originates from complex processes broadly categorized as organic and inorganic, predominantly including deep-Earth degassing, water-rock reactions, and radiolysis of water. (2) Hydrogen-rich accumulations exhibit widespread distribution, primarily occurring in rift systems, plate collision zones, subduction zones and their peripheries, as well as Precambrian iron-rich formations. (3) Natural hydrogen reservoirs form through dynamic accumulation processes requiring: high-quality source supply, favorable migration pathways and preservation conditions, and sustained influx exceeding leakage rates. (4) Favorable exploration targets should avoid microbial active zones and deep hydrogenation/hydrocarbon generation regions; current evidence suggests promising reservoirs occur in ultra-deep settings, peripheral areas of convergent zones, and shallow strata proximal to deep-seated faults. Exploration of natural hydrogen should prioritize evaluating the hydrogen anomalies to identify potential reservoirs and advance systematic comprehension of this emerging energy play.

Unconventional shale resources remain crucial to energy security. In situ conversion technology (ICP) offers a promising pathway for exploiting low–maturity shale, yet the distinct roles of kerogen and bitumen during thermal conversion are not fully understood. This study investigates the decomposition behavior of kerogen and extracted bitumen from the Shahejie Formation through gold–tube pyrolysis experiments at 50 MPa and heating rates of 2 °C/h and 20 °C/h. The results show that the yield curves of C₁, C₂–C₅, and C₆–C₁₄ generated from kerogen and bitumen exhibited similar trends. In contrast to the C₁₅₊ fraction from kerogen, which initially increased and then decreased, the yield of C₁₅₊ from bitumen began to decline from the onset of cracking. Additionally, the CO₂ generated from the kerogen continued to increase until the end of pyrolysis, whereas the CO₂ from the bitumen reached its maximum at an EasyRo of approximately 1.8%. The kinetic results show that bitumen has a higher activation energy for gas generation than kerogen, while kerogen has a higher activation energy for oil generation than bitumen. A heating program of 1 °C/day rate, 324 d duration, and a final temperature of 360 °C was applied to predict oil and gas generation during ICP. Below 326 °C, the proportion of C₁ and C₂–C₅ contributed by kerogen increased and exceeded 90%. Although kerogen’s contribution ratio of C₆–C₁₄ exhibited fluctuating variation characteristics, it remained above 50% across most of the intervals. The gas–to–oil ratio increased rapidly above 299 °C and reached 375 m³/m³ by the end of heating.

As a potential strategic resource of critical metals, deep-sea cobalt-rich crusts represent one of the most promising metal reservoirs within oceanic seamount systems, and their metallogenic mechanism constitutes a frontier topic in deep-sea geoscience research. This review focuses on the cobalt-rich crusts from the Magellan Seamount region in the northwestern Pacific and synthesizes existing geological, mineralogical, and geochemical studies to systematically elucidate their mineralization processes and metal enrichment mechanisms from a microstructural perspective, with particular emphasis on cobalt enrichment and its controlling factors. Based on published observations and experimental evidence, the formation of cobalt-rich crusts is divided into three stages: (1) Mn/Fe colloid formation—At the chemical interface between oxygen-rich bottom water and the oxygen minimum zone (OMZ), Mn²⁺ and Fe²⁺ are oxidized to form hydrated oxide colloids such as δ-MnO₂ and Fe(OH)₃. (2) Key metal adsorption—Colloidal particles adsorb metal ions such as Co²⁺, Ni²⁺, and Cu²⁺ through surface complexation and oxidation–substitution reactions, among which Co²⁺ is further oxidized to Co³⁺ and stably incorporated into MnO₆ octahedral vacancies. (3) Colloid deposition and mineralization—Mn–Fe colloids aggregate, dehydrate, and cement on the exposed seamount bedrock surface to form layered cobalt-rich crusts. This process is dominated by the Fe/Mn redox cycle, representing a continuous evolution from colloidal reactions to solid-phase mineral formation. Biological processes play a crucial catalytic role in the microstructural evolution of the crusts. Mn-oxidizing bacteria and extracellular polymeric substances (EPS) accelerate Mn oxidation, regulate mineral-oriented growth, and enhance particle cementation, thereby significantly improving the oxidation and adsorption efficiency of metal ions. Tectonic and paleoceanographic evolution, seamount topography, and the circulation of Antarctic Bottom Water jointly control the metallogenic environment and metal sources, while crystal defects, redox gradients, and biological activity collectively drive metal enrichment. This review establishes a conceptual framework of a multi-level metallogenic model linking macroscopic oceanic circulation and geological evolution with microscopic chemical and biological processes, providing a theoretical basis for the exploration, prediction, and sustainable development of potential cobalt-rich crust deposits.

Hydrothermal activity plays a critical role in ancient oceanic environments, organic matter accumulation, and metallic ore deposit formation. During the Early Cambrian, the development of hydrothermal systems in the southern Anhui Province of the Lower Yangtze Block has long attracted geological attention. This study focuses on the Lower Cambrian black shales of the Hongtaocun (HTC) section in the southern Anhui Province, employing major- and trace-element analyses, rare earth element (REE) geochemistry, and field-emission scanning electron microscopy (FE-SEM) observations to identify evidence for Early Cambrian hydrothermal activity on the Yangtze Platform and its controls on mineralization. Our results demonstrate that major-element proxies classify the HTC samples as biogenic, but this classification is demonstrably incorrect given the mineralogical and REE evidence, which highlights the limitations of major-element discrimination alone. Hyalophane (Hy) occurrence records Ba-rich hydrothermal fluids, while positive Eu anomalies in the REE patterns further corroborate hydrothermal influence. We, therefore, emphasize that major-element chemistry alone is insufficient to reliably identify hydrothermal processes. These findings substantially advance the discrimination criteria for ancient seafloor hydrothermal activity.