Support Data for Deciphering spatio-temporal variations in Holocene relative sea level in the South China Sea: from local reconstructions to a regional database

Chapter Two investigates the application of microfossils and δ13C and C/N geochemistry to develop high-resolution late Holocene RSL records from sediments in Deep Bay, located on the eastern side of the PRD. This chapter characterises the contemporary distribution of these proxies across three transects encompassing subtidal, intertidal (mudflat and mangrove), and upland environments. Partitioning Around Medoids (PAM) analysis is employed to characterise distinct biozones based on microfossil assemblages, while CCA examines the relationships between contemporary diatom and foraminiferal communities and environmental variables. Bayesian transfer functions (BTFs) are developed using modern foraminiferal and diatom assemblages, incorporating priors informed by δ13C and C/N geochemistry. These BTFs are applied to a sediment core obtained from a contemporary mangrove setting in Mai Po, Deep Bay, to evaluate their efficacy. The reconstructions are subsequently validated against local tide gauge data to assess the relative effectiveness of foraminiferal and diatom-based proxies in reconstructing RSL changes. This chapter has been submitted to Marine Geology.Chapter Three establishes the indicative meaning of S. cuccullata examining its contemporary vertical distribution along rocky coasts in Hong Kong, including periodic inundated thin S. cuccullata beds in elevated tidal pools. The elevation of the ancient oyster bed is resurveyed, and its morphology and depositional context are documented. Petrographic analysis and X-ray diffraction are used to evaluate the lithology and mineralogy of the ancient oyster bed, and therefore classify the reef and reconstruct the environment where it formed. Additionally, two new radiocarbon dates are obtained from samples collected at different elevations within the ancient bed to reconstruct mid-Holocene RSL in Hong Kong, constraining the timing and magnitude of the highstand in the region. This chapter has been prepared to be submitted to Palaeogeography, Palaeoclimatology, Palaeoecology.Chapter Four develops a quality-controlled Holocene RSL database for the SCS coast, incorporating SLIPs and limiting points derived from sedimentary, geomorphic, coral, fixed biological, and archaeological indicators spanning 14 ka to the present. Uncertainties associated with tidal range changes over the Holocene are addressed using a paleotidal model. Spatio-temporal fields of RSL change are reconstructed, with RSL and rates of RSL change estimated by applying SPTEHM to the database. Sensitivity tests are performed to examine the effects of global and Antarctic ice sheet deglaciation timing and variations in 3D Earth structure, including lateral heterogeneity, on GIA model predictions. The results are used to interpret regional and local processes driving spatio-temporal variability in RSL change. This chapter has been prepared to be submitted to Quaternary Science Reviews.

第二章探讨了微化石、碳同位素δ¹³C及C/N地球化学的应用，旨在从位于珠江三角洲（PRD，Pearl River Delta）东侧后海湾的沉积物中构建高分辨率晚全新世相对海平面（RSL，Relative Sea Level）记录。本章对潮下带、潮间带（泥滩与红树林）及陆地区域三条样带内上述代用指标的现代分布特征进行了刻画。研究采用围绕中心点划分聚类法（PAM，Partitioning Around Medoids）基于微化石组合划分出不同的生物带，同时利用典范对应分析（CCA，Canonical Correspondence Analysis）探究现代硅藻与有孔虫群落和环境变量之间的关联。基于现代有孔虫与硅藻组合构建贝叶斯传递函数（BTFs，Bayesian transfer functions），并纳入由δ¹³C及C/N地球化学得到的先验信息。将该BTFs应用于后海湾米埔现代红树林生境获取的沉积物岩芯，以评估其应用效能。随后将重建结果与当地验潮站数据进行验证，以对比基于有孔虫与硅藻的代用指标在重建RSL变化中的相对效果。本章已投稿至《Marine Geology》。
第三章针对S. cuccullata的指示意义展开研究，调查了其在香港岩质海岸的现代垂直分布特征，包括高潮汐池中周期性淹没的薄层S. cuccullata床。对古牡蛎床的高程进行了重新测量，并记录了其形态与沉积背景。采用岩相分析与X射线衍射对古牡蛎床的岩性与矿物学特征进行分析，进而对该礁体进行分类并重建其形成环境。此外，从古牡蛎床内不同高程的样品中获取了两组新的放射性碳定年数据，以此重建香港中全新世RSL，限定了该区域高海面的出现时间与幅度。本章已完成撰写，拟投稿至《Palaeogeography, Palaeoclimatology, Palaeoecology》。
第四章针对南海（SCS，South China Sea）沿岸构建了一套经过质量控制的全新世RSL数据库，纳入了源自14 ka至今的沉积、地貌、珊瑚、定置生物及考古学指标得到的海平面指数点（SLIPs，Sea Level Index Points）与极限点位。利用古潮汐模型解决全新世潮汐范围变化带来的不确定性。基于该数据库应用SPTEHM估算RSL与RSL变化速率，重建RSL变化的时空场。开展敏感性测试，探究全球及南极冰盖冰消作用时间、三维地球结构（包括横向非均质性）对冰后回弹（GIA，Glacial Isostatic Adjustment）模型预测结果的影响。利用研究结果解释驱动RSL变化时空变异的区域与局地过程。本章已完成撰写，拟投稿至《Quaternary Science Reviews》。