Unraveling the complex story of ancient shorelines: how deltas and beach bars weave together to shape hidden reservoirs

Higher Education Press

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(a) Classification of sedimentary models and development control factors of delta - beach bar composite sand bodies;(b) Composite sand body of Quanzigou braided river delta distributary channel-coastal Bar on west bank of Daihai Lake

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Credit: HIGHER EDUCATON PRESS

New research systematically classifies the formation and distribution of delta-beach bar composite sand bodies, offering a refined framework for energy exploration and paleogeographic reconstruction.

The study of sedimentary systems has long relied on models that describe sand bodies formed by single processes, such as river channels, deltas, or beach bars. While these models have greatly advanced hydrocarbon exploration, they often fall short in capturing the complexity of many real-world reservoirs, where multiple depositional processes interact over time. In particular, the interplay between river-derived deltaic sands and lake or marine wave-reworked beach bars has remained underexplored, leading to oversimplified interpretations in subsurface mapping and resource assessment. A recent study published in the Journal of Palaeogeography (Chinese Edition)(Vol. 27, No. 4, 2025) tackles this gap by synthesizing decades of research into what the authors term “delta-beach bar composite sand bodies.”

Led by Professor Ji Youliang and his team from China University of Petroleum (Beijing), the work draws on extensive field observations, modern sedimentary analogs, and subsurface case studies to propose a unified genetic and descriptive framework for these composite systems. The researchers emphasize that composite sand bodies arise from the dynamic interaction of fluvial input and lacustrine or marine hydrodynamics—including waves, longshore currents, and rip currents—coupled with frequent lake- or sea-level fluctuations that drive shoreline migration. These processes rework, redistribute, and stack sands into intricate architectures that cannot be explained by single-process models.

The study identifies four principal distribution patterns for delta-beach bar composites: the shoreline migration–delta lateral margin bar model, the delta front estuary bar–coastal bar model, the delta distributary channel–coastal bar model, and the delta front estuary bar–carbonate bar superposition model. Each pattern reflects specific geomorphic and hydrodynamic settings, such as coastline curvature, underwater uplift, or gentle shelf slopes, which jointly control where and how these sand bodies develop. Key controlling factors include autogenic and allogenic sedimentary cycles, composite hydrodynamic actions, topographic influences, mixed sedimentation (e.g., clastic and carbonate), and episodic depositional events.

Beyond classification, the research highlights the practical importance of recognizing composite sand bodies in hydrocarbon exploration. Their interconnected nature often results in enhanced reservoir connectivity and volume, which can significantly impact resource estimates and development strategies. The proposed models provide a more geologically realistic basis for paleogeographic mapping and subsurface prediction, moving beyond conventional single-facies approaches.

This work represents a meaningful step toward integrating multi-process sedimentology into applied geoscience. By bridging the gap between deltaic and shoreface systems, it offers a versatile toolkit for interpreting complex reservoirs in rift basins, continental shelves, and ancient sedimentary records worldwide. The findings underscore the need for future studies to combine high-resolution seismic data, outcrop analogs, and process-based numerical modeling to further quantify the architecture and fluid flow properties of these composite systems.

 

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Journal

Journal of Palaeogeography

DOI

10.7605/gdlxb.2025.089 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

A review of research progress and prospects on depositional models and genetic mechanisms of delta-beach bar composite sand bodies

 

Decoding Earth’s ancient rhythms: how planetary orbits shape oil-rich shale

Higher Education Press

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Cyclical stratigraphic analysis of Lower Liang 2 Submember of Well Z1 in the Fuxing area of Sichuan Basin. And the lithofacies deposition model under the control of eccentricity in the lower Liang 2 submember in Fuxing area of Sichuan Basin

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Credit: HIGHER EDUCATON PRESS

High-resolution study of Jurassic mudstones in China’s Sichuan Basin reveals that astronomical cycles control climate, sedimentation, and organic matter accumulation—key insights for global shale oil exploration.

As global energy demand continues to rise, unconventional resources such as shale oil have become increasingly vital. However, predicting the distribution of high-quality organic-rich shale remains a significant challenge, largely due to incomplete understanding of the fine-scale depositional processes that govern their formation. A new study published in the Journal of Palaeogeography (Chinese Edition) (Vol. 27, No. 5, 2025) advances this field by demonstrating how Earth’s astronomical cycles—specifically variations in orbital eccentricity—exert a dominant control on lacustrine shale deposition, organic enrichment, and lithofacies architecture. The research, conducted on the Jurassic Lianggaoshan Formation in the Sichuan Basin, China, provides a high-resolution climatic and sedimentological framework that enhances the predictability of shale oil reservoirs.

Previous studies have recognized that astronomical forcing influences paleoclimate and sedimentation over geological timescales, yet most focus has been on marine or deep-time records. In contrast, lacustrine systems—especially those deposited in continental interiors—are highly sensitive to orbital-driven climate change, but their high-frequency depositional response has been less systematically decoded. The research team, led by Professor Xian Benzhong from China University of Petroleum (Beijing), addressed this gap by applying cyclostratigraphic analysis to the Lower Liang 2 Submember in the Fuxing area of the Sichuan Basin.

The investigators used natural gamma ray (GR) logging curves as a paleoclimate proxy, combined with detailed core observations, geochemical elemental analysis, and total organic carbon (TOC) measurements. Through advanced time-series analysis using the Acycle software, they detected multiple Milankovitch cycles within the shale-rich interval, including long eccentricity (405 ka), short eccentricity (128 ka), obliquity (43 ka), and precession (21 ka) signals. These cycles were correlated with fourth- and fifth-order sequence stratigraphic units, enabling the establishment of a high-frequency chronostratigraphic framework with an average sedimentation rate of approximately 4.2 cm/kyr—one of the first such precise reconstructions in a Jurassic lacustrine setting in this region.

The results reveal a clear astronomical pacing of paleoenvironmental conditions. During high eccentricity periods, enhanced seasonal contrast led to warmer, wetter climates, increased terrestrial input, lake expansion, and elevated primary productivity. These conditions favored the deposition of organic-rich laminated mudstone (Lithofacies Association A) in deep-water settings. Conversely, low eccentricity intervals corresponded to drier climates, reduced runoff, intensified weathering, and lower lake levels. Under these conditions, deltaic sand bodies developed on upper slopes (Lithofacies Association B2), while hyperpycnal flows delivered sandy sediments into deeper waters (Lithofacies Association B1). Importantly, the study establishes that long eccentricity (405 ka) exerts the primary control on climate evolution, organic matter accumulation, and basin-scale lithofacies distribution, whereas short eccentricity (128 ka) modulates these patterns at higher frequency.

One of the key innovations of this work is its integrated demonstration of orbital control on both normal mudstone deposition and event sedimentation (hyperpycnites) in a lake basin. By linking elemental geochemical proxies (e.g., Sr/Cu, C-value, Sr/Ba, Ti/Al) and TOC trends directly to eccentricity cycles, the researchers provide a mechanistic understanding of how astronomical forcing regulates weathering, nutrient supply, water column stratification, and ultimately, the preservation of organic carbon. The high-resolution correlation across three wells also confirms that even in deep-water settings, stratigraphic gaps can occur, challenging previous assumptions about continuous sedimentation in lake centers.

These findings carry important implications for shale oil exploration in continental basins worldwide. By recognizing that the best organic-rich shale intervals are preferentially deposited during specific orbital configurations—namely high eccentricity phases—explorationists can better predict the vertical and lateral distribution of “sweet spot” in subsurface shale formations. The high-resolution sequence framework also offers a powerful tool for regional correlation and reservoir modeling, reducing uncertainty in targeting producible zones.

This research not only advances the understanding of terrestrial sedimentology under astronomical forcing but also delivers a practical methodology for applying cyclostratigraphy in resource evaluation. As energy transitions continue to underscore the importance of unconventional hydrocarbons, such integrative studies that bridge paleoclimate science and petroleum geology will play an increasingly vital role in sustainable resource development.

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Journal

Journal of Palaeogeography

DOI

10.7605/gdlxb.2025.038 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Lithofacies development patterns of lacustrine shales under astronomical forcing: a case study of the Lianggaoshan Formation in Sichuan Basin

 

January 2026 issues of APA journals feature new research on autism, pediatric anxiety, psychedelic therapy, suicide prevention and more

American Psychiatric Association

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WASHINGTON, D.C., Jan. 5, 2026 — The latest issues of four American Psychiatric Association journals (The American Journal of Psychiatry, Psychiatric Services, American Journal of Psychotherapy and Psychiatric Research and Clinical Practice) are now available online.

The January issue of The American Journal of Psychiatry brings together research on externalizing disorders, pediatric anxiety, autism, and inflammation-related depression. Highlights of the issue include:

 

• The effect of anti-inflammatory treatment on depressive symptom severity in depressed individuals with elevated inflammation
• A possible biomarker for pediatric anxiety disorder (lead author Julia Linke, Ph.D., is the guest on January's AJP Audio podcast episode).
• Strong evidence for the role of glutamatergic differences in understanding the biology of autism (AJP Deputy Editor Daniel Pine, M.D., highlights the study in this video).
• How the genetic architecture of impulsivity—mapped by integrating genomic, imaging, and clinical data—reveals neurodevelopmental pathways that shape risk across the lifespan.
• An overview discussing refinement of the ADHD phenotype (AJP Deputy Editor Daniel Pine highlights the study in this video).

The January issue of Psychiatric Services features the following:

 

• Crisis Outreach, Treatment Engagement, and Outcomes After Suicide Risk Screening in a Comprehensive Mental Health Platform
• Stepped Care Interventions for Psychosis Risk: Findings from Clinical High Risk for Psychosis Grantee Programs
• Cognitive-Behavioral Therapy and Support Services for People with Serious Mental Illness Who Were Experiencing Homelessness
• Changes in Police Contact After Admission to the Assertive Community Treatment with Police Integration Program

 

American Journal of Psychotherapy, Volume 78, Issue 4, features:

 

• Considerations for Cross-Cultural Adaptations and Implementation of Interpersonal Psychotherapy
• The Role of Touch in Psychedelic Therapy
• The Role of Patient-Avatar Dynamics in Avatar Therapy
• Mood Lifters for Bipolar Disorder: A Feasibility Study
• Psychotherapy for Delusional Disorder: Theoretical Models and Therapeutic Techniques

 

 

Psychiatric Research and Clinical Practice, Volume 7, Issue 4, features:

 

• Quantifying the Societal Impacts of Schizophrenia
• Five‐Year Implementation of Zero Suicide: Lessons Learnt from an Academic Health System
• Psychiatric Advance Directives: An Analysis of Current Usage at a Large County Hospital
• Psychiatric Advance Directives Among Veterans with Serious Mental Illness

Journalists who wish to access the publications should email press@psych.org.

American Psychiatric Association
The American Psychiatric Association, founded in 1844, is the oldest medical association in the country. The APA is also the largest psychiatric association in the world with more than 39,200 physician members specializing in the diagnosis, treatment, prevention and research of mental illnesses. APA’s vision is to ensure access to quality psychiatric diagnosis and treatment. For more information, please visit www.psychiatry.org.

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Journal

American Journal of Psychiatry

 

Private equity acquired more than 500 autism centers over the past decade, new study shows

A new study from Brown University researchers highlights a push from private equity investors into autism therapy centers across the U.S.

Brown University

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PROVIDENCE, R.I. [Brown University] — Private equity firms have acquired more than 500 autism therapy centers across the U.S. over the past decade, with nearly 80% of those acquisitions occurring over a four-year span, according to a new study from researchers at the Brown University Center for Advancing Health Policy through Research.

Study author Yashaswini Singh, a health economist at Brown’s School of Public Health, said the work highlights how financial firms are rapidly moving into a sensitive area of health care without much public scrutiny or data on where this is happening or why.

“The big takeaway is that there is yet another segment of health care that has emerged as potentially profitable to private equity investors and it is very distinct from where we have traditionally known investors to go, so the potential for harm can be a lot more serious,” Singh said. “We're also dealing with children who are largely insured by Medicaid programs, so if private equity increases the intensity of care, what we're really looking at are impacts to state Medicaid budgets down the road.”

The findings of the analysis were published in JAMA Pediatrics and offers one of the first national assessments of private equity’s growing role in autism therapies and services. Autism diagnoses among U.S. children have risen sharply in recent years, nearly tripling between 2011 and 2022, and the condition has been in the national spotlight amid political debate falsely linking autism to childhood vaccines.

The researchers, Singh said, did not evaluate the impacts of private equity ownership on access to treatment, quality of care or the experience of families seeking services. The findings do suggest that investment has been concentrated in states with higher rates of autism diagnoses among children and states that have fewer limits on insurance coverage. 

The researchers identified a total of 574 autism therapy centers owned by private equity firms as of 2024, spanning 42 states. Most of those centers were acquired between 2018 and 2022, the result of 142 separate deals. The largest concentrations of centers were in California (97), Texas (81), Colorado (38), Illinois (36) and Florida (36). Sixteen states had one or no private equity-owned clinics at the end of 2024.

States in the top third for childhood autism prevalence were 24% more likely to have private equity–owned clinics than others, according to the study.

The scale and speed of acquisitions underscore the growing trend of private equity’s entry into the market. According to Singh, researchers were prompted to investigate after hearing anecdotal reports from families and health providers about changes following private equity takeovers.

The primary concern is private equity firms putting money over families, said Daniel Arnold, a senior research scientist at the School of Public Health.

“It's all about the financial incentives,” Arnold said. “I worry about the same types of revenue generating strategies seen in other private equity-backed settings. I worry about children receiving more than the clinically appropriate amount of services and worsening disparities in terms of which children have access to services.”

To establish a baseline of where private equity firms are investing and why, the team used a mix of proprietary databases, public press releases and manual verification of archived websites to track changes in ownership. Unlike public companies, private equity firms and private practices are not required to disclose acquisitions, making data collection challenging and labor-intensive.

The team is now seeking federal funding to examine how private equity ownership affects outcomes, including changes in therapy intensity, medication use, diagnosis age or how long children stay in treatment. They will determine whether these investments are helping meet real needs or are primarily a way to make money.

“Private investors making a little bit of money while expanding access is not a bad thing, per se,” Singh said. But we need to understand how much of a bad thing this is and how much of a good thing this is. This is a first step in that direction.”

This study received funding from the National Institute on Aging (R01AG073286) and the National Institute on Mental Health (R01MH132128).

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Journal

JAMA Pediatrics

DOI

10.1001/jamapediatrics.2025.5443 

Article Title

Private Equity in Autism Services

Article Publication Date

5-Jan-2026