High-resolution Holocene marine sediment records are limited, which hampers our understanding of paleomonsoon evolution. Continental shelf sediment records are derived mainly from terrestrial weathering products and are thus often sensitive to paleoclimate variations. In this study, the grain size and magnetic mineral composition of a well-dated sediment core (YJ Core) from the northern inner shelf of the South China Sea (SCS) were analyzed to provide a high-resolution record of the Holocene evolution of the East Asian summer monsoon (EASM). These magnetic and grain size records indicate that EASM intensity followed a general declining trend between approximately 6800 and 2000 cal yr BP. This general pattern is synchronous with other geologic archives from monsoon regions, and can be attributed to solar radiation forcing in the Northern Hemisphere. On centennial timescales, a weak EASM closely coincides with periods of weak solar activity. In addition, spectral analysis of clays reveals five prominent cycles, with periodicities of approximately 364, 202, 158, 119, and 104 years, which correspond to solar activity cycles. The similarities between the cyclicities of the Asian monsoon signal in sedimentary records and those of solar activity demonstrate that solar forcing has a relatively large influence on the centennial-scale variability of the EASM.

中文翻译：

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过去7500年南海北部东亚夏季风的高分辨率沉积记录

高分辨率全新世海洋沉积物记录有限，这阻碍了我们对古季风演化的理解。大陆架沉积物记录主要来自陆地风化产物，因此通常对古气候变化敏感。在这项研究中，分析了南海北部内陆架 (SCS) 年代久远的沉积物核心 (YJ 核心) 的粒度和磁性矿物组成，以提供全新世演化的高分辨率记录。东亚夏季风 (EASM)。这些磁性和晶粒尺寸记录表明 EASM 强度在大约 6800 和 2000 cal BP 之间遵循总体下降趋势。这种一般模式与季风区的其他地质档案同步，可归因于北半球的太阳辐射强迫。在百年时间尺度上，弱 EASM 与弱太阳活动时期非常吻合。此外，粘土的光谱分析揭示了五个突出的周期，周期约为 364、202、158、119 和 104 年，对应于太阳活动周期。沉积记录中亚洲季风信号的周期性与太阳活动的周期性之间的相似性表明，太阳强迫对东亚夏季风百年尺度变化的影响较大。