Dahu Lake paleoclimate data

The <b>Dahu_Lake_data.xlsx</b> contains three sheets: <b>Organic, Geochemical,</b> <b>Diatom</b>, and <b>14C</b>.The <b>Organic</b> sheet includes carbon and nitrogen contents, elemental ratios, and the carbon isotopic composition of organic matter in core sediments from Dahu Lake, northern Taiwan. These proxies were used to infer changes in organic matter sources, which provided insights into runoff conditions and helped identify typhoon events in the region.The <b>Geochemical</b> sheet contains the concentrations of leached elements (K, Mn, Na, Sr, Ti, Al, Fe) and K/Na ratios in core sediments. This data helped track changes in the intensity of chemical weathering in the region, supporting the interpretations derived from the organic data.The <b>Diatom</b> sheet presents the abundances of diatoms categorised by their preferred habitats, including <b>planktonic, benthic,</b> and <b>epiphytic</b> species, along with their total concentrations in the core sediments.The <b>14C </b>sheet contains the radiocarbon ages of the samples at different depths using different materials.<b>Abstract of the Manuscript</b>To enhance the understanding of the Holocene climate in northern Taiwan, where early to mid-Holocene paleoclimate data is sparse, a study was designed to collect a lake core from Dahu Lake in the Ilan Plain, located in the northeastern part of Taiwan. To investigate the climate, a multiproxy approach was employed, examining geochemical elements, diatoms, total organic carbon (TOC), total nitrogen (TN), their ratios (TOC/TN), and carbon isotopic compositions (δ¹³Corg). Diatom data indicated that the area primarily functioned as a riverine system, with occasional time frames of lake level situations during 6.6, 5.0, 3.7, 2.1, 1.0, and 0.4–0.2 cal kyr BP. The multiproxy analysis, which included TOC, TN, TOC/TN, and δ¹³C_org, suggested substantial terrestrial input. Elevated levels of Ti and the presence of illite pointed to sporadic overflow from the Lanyang River. Additionally, high K/Na ratios indicated intense chemical weathering. These combined findings implied increased typhoon activity during the periods 7.7–4.9, 3.8–3.6, 3.3–2.8, 2.2–2.0, 1.2, 1.0, and 0.5–0.2 cal kyr BP. In contrast, the periods between these frequent typhoons or wetter climate events were relatively drier, as evidenced by sediments that primarily originated from the Ilan River. The typhoon activities were a response to a strong EASM and La Niña-like conditions in the Pacific Ocean. In contrast, the drier periods were characterized by strong EAWM and El Niño-like conditions in the region.<br><b>Dahu_Lake_data.xlsx</b> 包含四个工作表：<b>有机质（Organic）</b>、<b>地球化学（Geochemical）</b>、<b>硅藻（Diatom）</b>与<b>放射性碳（14C）</b>。 <b>有机质（Organic）</b>工作表收录了中国台湾北部大湖湖芯沉积物中有机质的碳、氮含量、元素比值以及碳同位素组成。上述代用指标被用于反演有机质来源的变化，借此研判径流状况并识别区域内的台风事件。 <b>地球化学（Geochemical）</b>工作表包含湖芯沉积物中淋溶元素（K、Mn、Na、Sr、Ti、Al、Fe）的浓度及K/Na比值。此类数据可用于追踪区域化学风化强度的变化，辅助验证有机质数据集的解译结果。 <b>硅藻（Diatom）</b>工作表呈现了按偏好生境分类的硅藻丰度，包括浮游（planktonic）、底栖（benthic）与附生（epiphytic）物种，同时记录了沉积物中硅藻的总浓度。 <b>放射性碳（14C）</b>工作表收录了不同深度沉积物样品基于不同测年材料得到的放射性碳年代数据。 <b>研究论文摘要（Abstract of the Manuscript）</b> 为加深对中国台湾北部全新世气候的认识——该区域早-中全新世古气候数据较为匮乏——研究团队于台湾东北部宜兰平原的大湖采集了湖芯样品。为开展气候研究，本研究采用多代用指标分析法，检测了地球化学元素、硅藻、总有机碳（total organic carbon, TOC）、总氮（total nitrogen, TN）、二者比值（TOC/TN）以及碳同位素组成（δ¹³Corg）。 硅藻数据显示，该区域整体以河流系统为主，在6.6、5.0、3.7、2.1、1.0以及0.4~0.2 cal kyr BP时段曾出现阶段性湖相环境。 多代用指标分析（涵盖TOC、TN、TOC/TN与δ¹³Corg）结果表明，研究区域存在显著的陆源物质输入。Ti元素浓度升高以及伊利石的存在，指示兰阳河曾出现间歇性溢流。此外，较高的K/Na比值表明当时化学风化作用强烈。综合上述结果可知，7.7~4.9、3.8~3.6、3.3~2.8、2.2~2.0、1.2、1.0以及0.5~0.2 cal kyr BP时段台风活动较为频繁。与之相对，台风与强降水事件之间的时段气候相对干燥，沉积物主要来源于宜兰河。该区域的台风活动响应于太平洋地区强盛的东亚夏季风（East Asian Summer Monsoon, EASM）与类拉尼娜（La Niña）海温异常状态；而干燥时段则对应强盛的东亚冬季风（East Asian Winter Monsoon, EAWM）与类厄尔尼诺（El Niño）海温异常背景。