A new peer-reviewed study published in Palaeogeography, Palaeoclimatology, Palaeoecology provides detailed sedimentological, geochronological, and palynological evidence for paleoclimate and sea-level changes in the Chaoshan Plain of southeastern China since the late Pleistocene. Led by Pan Zhang, Yanbo Zhang, Feng Li, Junwu Shu, Banghua Lu, Huaguo Liu, Qichao Jia, Changlong Li, and Peifeng Xie, the research draws on a 78-meter sediment core labeled BZK2 drilled in the Rongjiang River plain portion of the Chaoshan region.

The full publication is available at https://www.sciencedirect.com/science/article/abs/pii/S0031018226004773. The authors integrated pollen analysis with sediment facies descriptions and dating via quartz optically stimulated luminescence (OSL) and radiocarbon methods to build a high-resolution record spanning Marine Isotope Stages (MIS) 5 through the present.

Regional Context of the Chaoshan Plain

The Chaoshan Plain covers roughly 4,700 square kilometers along the northern coast of the South China Sea in eastern Guangdong Province. It formed through alluvial processes of the Hanjiang, Rongjiang, and Lianjiang rivers. These coastal lowlands sit at the interface of fluvial and marine influences, making them sensitive recorders of past sea-level fluctuations and monsoon-driven climate shifts. Comparable studies have focused more intensively on the nearby Pearl River Delta, leaving gaps in understanding for the Chaoshan area, particularly the timing of the first major marine transgression.

Core Collection and Analytical Methods

In 2024, researchers recovered core BZK2 at coordinates 23.55°N, 116.35°E and 7 meters above sea level using a rotating drilling system. Recovery reached approximately 98 percent. Each two-meter section was sealed in PVC sleeves, split lengthwise, and described for lithology, color, texture, and sedimentary structures. Fourteen stratigraphic units were identified and grouped into fluvial-dominated deposits below 28 meters depth and coastal-influenced facies above that level.

Palynology involved high-resolution sampling of pollen and spores to reconstruct vegetation history. Geochronology combined OSL dating of quartz grains, which measures the last exposure of sediment to sunlight, with radiocarbon dating of organic material. This multiproxy approach allowed precise correlation of environmental changes across time.

Key Stratigraphic and Chronological Findings

The lower portion of the core consists primarily of fluvial sediments, indicating terrestrial river-dominated environments. Above 28 meters, the sequence transitions to intertidal, estuarine, and coastal swamp deposits, marking increased marine influence. Chronological data place the onset of this major marine transgression during MIS 5, approximately 130,000 to 71,000 years ago, rather than the previously debated MIS 3 interval.

This timing aligns with independent records from the Pearl River Delta and resolves earlier discrepancies in regional sea-level reconstructions. The evidence supports a warmer and wetter MIS 5 interval compared with the Holocene, based on the presence of thermophilous mangrove taxa such as Sonneratia alongside other indicators.

Photo by Artem Beliaikin on Unsplash

Vegetation and Climate Reconstruction from Pollen Data

Pollen assemblages throughout the record show persistent dominance of evergreen broad-leaved forest taxa, including Castanopsis, Cyclobalanopsis, and Altingia types. These reflect stable warm-humid conditions under the East Asian monsoon during both MIS 5 and MIS 1 (the current interglacial). Exclusive occurrences of certain thermophilous species in the late Pleistocene portion underscore that MIS 5 supported more extensive warmth and moisture than modern conditions.

Mangrove pollen further highlights coastal ecosystem responses to sea-level rise and climatic optima. The record demonstrates how vegetation communities shifted in tandem with depositional environments, providing a terrestrial complement to marine sediment archives from the South China Sea.

Late Holocene Human Impacts and Agricultural Onset

A marked rise in Poaceae (grass) pollen, accompanied by the consistent appearance of rice-type pollen after approximately 3,000 years ago, signals the intensification of rice-based agriculture. This anthropogenic signal overlays longer-term natural variability driven by climate and sea level. The findings illustrate how human activity transformed coastal landscapes in the region during the late Holocene, adding an important layer to interpretations of environmental change.

Implications for Understanding East Asian Monsoon Dynamics

The Chaoshan record contributes to broader knowledge of monsoon variability and its interaction with global sea-level changes. By documenting a clear transition from fluvial to marine-influenced sedimentation and linking it to specific MIS intervals, the study refines models of coastal response in subtropical East Asia. Such data help contextualize modern vulnerabilities of densely populated deltas to rising seas and shifting precipitation patterns.

Broader Relevance to Coastal Research and Management

Coastal plains worldwide face similar pressures from sea-level rise and land-use change. The detailed facies framework and vegetation history from core BZK2 offer a template for comparable studies in other monsoon-influenced regions. Policymakers and environmental scientists can draw on these insights when planning adaptation strategies for areas like the Chaoshan Plain, where agriculture and urban development intersect with dynamic natural systems.

Photo by Artem Beliaikin on Unsplash

Future Research Directions and Career Opportunities

The publication underscores the value of integrated multiproxy approaches in Quaternary science. Emerging scholars interested in paleoenvironmental reconstruction may explore related fieldwork opportunities or laboratory techniques in sediment analysis and palynology. Institutions conducting coastal research continue to seek expertise in geochronology and climate modeling to extend these findings across additional sites.

Conclusion

This study by Pan Zhang and colleagues delivers a robust, chronologically constrained view of environmental evolution in the Chaoshan Plain. It clarifies the timing of marine transgression, highlights climatic differences between MIS 5 and the Holocene, and documents the imprint of early agriculture. Readers can access the complete analysis, including figures and supplementary data, through the provided ScienceDirect link. The work stands as a significant addition to the literature on late Quaternary changes along China’s southeastern coast.