Yifan Li
Zhiyang Li
Jianguo Zhang
Zhen Qiu
George Kontakiotis
Junwen Peng
Youwei Wang- 1School of Energy and Resources, China University of Geosciences, Beijing, China
- 2School of Engineering, Texas A&M International University, Laredo, TX, United States
- 3Research Institute of Petroleum Exploration and Development (RIPED), PetroChina, Beijing, China
- 4Department of Historical Geology and Paleontology, Faculty of Geology and Geoenvironment, School of Earth Sciences, National and Kapodistrian University of Athens, Athens, Greece
- 5Oklahoma Geological Survey, University of Oklahoma, Norman, OK, United States
- 6Department of Environmental Sciences, University of Virginia, Charlottesville, VA, United States
Editorial on the Research Topic
Fine-grained sedimentary rocks: sedimentary processes, diagenesis, geochemistry and their relationship with critical geological events
Fine-grained sedimentary rocks are increasingly studied for their complex depositional processes, high organic content, reservoir potential, metal enrichment, and geochemical records of paleoenvironments (Ettensohn et al., 1987; Wignall, 1994; Stow et al., 2001; Aplin et al., 2011; Shahzad et al., 2024). Once seen as homogeneous suspension-settled deposits, flume experiments and sedimentological studies have revealed that they can form under high-energy conditions, influenced by floods, storms, and bottom currents (Schieber et al., 2007; Bohacs et al., 2014; Macquaker et al., 2014; Li et al., 2022; Mehmood et al., 2023). Additionally, finegrained sedimentary rocks may receive sediments of various origins and can be characterized by a complex composition comprising clay minerals, quartz, carbonates, feldspars, sulfides, biogenic debris, and organic matter (Taylor and Macquaker, 2002; Macquaker and Adams, 2003; Milliken, 2014; Camp et al., 2015). Diagenesis in these rocks is governed by mass-balance, fluid transport, and organic-inorganic interactions (Morad et al., 2000; Cobbold et al., 2013; Liang et al., 2018). Geochemical proxies link their formation to major tectonic and environmental events, including rifting, glaciation, volcanism, anoxia, mass extinctions, and hydrothermal activity (Algeo et al., 2012; Trabucho-Alexandre et al., 2012; Li et al., 2015; Qiu et al., 2022; Shen et al., 2025; Derkowski et al., 2013). These insights are vital to sedimentary and diagenetic theory—especially unconventional petroleum sedimentology (Qiu et al., 2020; Zou et al., 2022)—and to understanding Earth’s sphere-system evolution.
This Research Topic comprises ten papers presenting advances in the study of fine-grained sedimentary rocks from three perspectives: depositional processes, diagenetic mechanisms, and geochemical characteristics. Rocks focused in this volume encompass both marine and continental mudstones and shales, spanning strata from the Cambrian to the Eocene, and therefore are broadly representative. Through these case studies, we aim to further enrich the theoretical framework surrounding fine-grained sedimentary rocks.
Sedimentary processes
Wen et al. investigated the Beipiao Formation in western Liaoning, Northeast China, and identified lithofacies formed under the influence of volcanic activities and sediment-gravity flows. Three depositional environments—shallow lake, semi-deep/deep lacustrine, and fan delta—were defined, with basin evolution transitioning from fan delta to deep lake and back, interbedded with volcanic deposits. Volcanism enhanced nutrient supply and organic matter preservation, while gravity flows transported plant fragments to deep lakes, leading to the enrichment of Type III kerogen.
Feng and Zhang analyzed the ShangGanchaigou Formation in the western Qaidam Basin, Northwest China, and identified seven architectural elements (distributary channels, bars, algal mounds, etc.) and three facies belts (proximal delta front, middle isolated lobes, distal algalmarl complexes). Short-term base-level cycles were documented as the dominant factor producing frequent facies variations. Reservoir connectivity was documented to decrease lakeward, revealing challenges in predicting heterogeneous reservoirs.
Diagenesis
Zhang et al. examined coevolution of minerals in lacustrine mudstones from Bohai Bay Basin, East China. Fibrous calcite/ankerite precipitated in primary laminar fractures during peak organic-acid release, with elements supplied by early carbonate dissolution and smectite–illite transformation. Clay alteration led to the formation of microcrystalline quartz, feldspar dissolution, and the increase in pH allowed authigenic albite to form. Authigenic carbonates and colloidal pyrite regulated pore-fluid chemistry, while variations in organic matter governed pore pressure, acid levels, and diagenetic pathways.
Yuan et al. studied tight sandstones of the Jurassic Lianggaoshan Formation in the eastern Sichuan Basin, Southwest China, and identified various facies associated with subaqueous distributary channels and mouth bars. Strong compaction/cementation led to reduction of porosity, while chlorite coatings and weak dissolution preserved pores. Five diagenetic facies were classified, with Type III (chlorite-coating) and IV (weak dissolution) in coarse-grained channels showing high AC, low GR/DEN/RT as optimal reservoirs.
Lin et al. studied analcime formation in Middle Permian reservoirs in the Jinan Sag, Junggar Basin, Northwest China. Analcime was originated from early alkaline hydrolysis of volcanic debris under specific conditions, forming low-silica, Al-rich, Na-poor varieties. Cementation reduced primary porosity, but acidic fluids from oil/gas charging dissolved analcime, generating secondary pores via albitization. Reservoir quality was enhanced by formation of intragranular pores through dissolution of analcime, feldspar or lithic fragments.
Guo et al. investigated glutenite compaction using a self-designed diagenetic simulation system, addressing the lack of quantitative studies on complex rock fabrics. Experiments revealed segmented logarithmic relationships between porosity and depth during mechanical compaction, with larger grains aiding in pore preservation. A 30% sand content in gravel formed stable secondary structures optimizing pressure-bearing capacity, while high heterobase content reduced primary pores.
Ge et al. examined Niutitang shale gas across four palaeouplifts in the Sichuan Basin, Southwest China, showing that structural preservation, thermal maturation, and sedimentary subfacies control enrichment and that thrust-nappe lower plates and deepwater trough facies were recognized as prime exploration targets.
Geochemistry
Lu et al. investigated Qiongzhusi Formation shale from three wells in southern Sichuan Basin, Southwest China, by analyses of lithofacies, mineralogy, TOC, trace elements, and isotopes. They defined two depositional end-members in a fault-controlled, moderately restricted setting: (1) organic-rich black shale formed under anoxic-suboxic conditions during periods of low chemical weathering, cold-arid climate, and high productivity; and (2) organic-lean grey shale deposited under suboxic-oxic conditions during periods of similarly low weathering intensity and aridity but reduced productivity.
Gao et al. analyzed fine-grained floodplain deposits in the Greater Green River Basin, southwestern Wyoming, United States of America. They used paleosol morphology, bulk organic δ13C, leaf-wax δ13C and δD, and CIA-K–derived MAP to reconstruct LPEE continental hydroclimate. They identified the PETM by a ∼4‰–5‰ negative carbon isotope excursion and a 30‰–50‰ leaf wax n-alkanes δ Dn-alk increase. Paleosols indicate generally humid–warm conditions with transient drying during the PETM, with pCO2 of 600–900 ppm reconstructed through the integration of δ13Corg with carbonate δ13C.
Wang et al. reconciled Qingshankou Formation mud/silt stratigraphy in the southern Songliao Basin, Northwest China, by linking gamma/density logs to astronomical cycles, and developed a high-resolution, isochronous framework. They showed that tectonics and orbital climate paced rhythmic sand–mud progradation and proposed a “synchronous heterotopy” lake-delta model with overfilling strata lagging eccentricity peaks, whereas balanced - filling strata coinciding with them.
Author contributions
YL: Writing – original draft, Writing – review and editing. ZL: Writing – original draft, Writing – review and editing. JZ: Writing – review and editing. ZQ: Writing – review and editing. GK: Writing – review and editing. JP: Writing – review and editing. YW: Writing – review and editing.
Funding
The author(s) declare that financial support was received for the research and/or publication of this article. This work was supported by the National Natural Science Foundation of China (Grants 42272173, U24B6001), and the National Key Research and Development Program of China (Grant Nos. 2023YFF0804300, 2023YFF0804302).
Conflict of interest
Author ZQ was employed by Petrochina.
The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Generative AI statement
The author(s) declare that no Generative AI was used in the creation of this manuscript.
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Keywords: sedimentary process, sedimentary geochemistry, diagenenesis, shales and mudstones, unconventional reservoir, geological event
Citation: Li Y, Li Z, Zhang J, Qiu Z, Kontakiotis G, Peng J and Wang Y (2025) Editorial: Fine-grained sedimentary rocks: sedimentary processes, diagenesis, geochemistry and their relationship with critical geological events. Front. Earth Sci. 13:1625168. doi: 10.3389/feart.2025.1625168
Received: 08 May 2025; Accepted: 13 May 2025;
Published: 22 May 2025.
Edited and reviewed by:
Valerio Acocella, Roma Tre University, ItalyCopyright © 2025 Li, Li, Zhang, Qiu, Kontakiotis, Peng and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Yifan Li, bGl5aWZhbkBjdWdiLmVkdS5jbg==