Geochemical, pollen and bulk geochemistry record of MIS11-1 from Lake Petén Itzá (Site PI-1) Guatemala@en

We present data on bulk density, inorganic geochemistry (Ti, Ca, Al, Mn, and Fe), pollen (Quercus, Moraceae, Pinus, tropicality index), and sediment geochemistry (TOC, TN, TOC/TN) from Lake Petén Itzá. In 2006, Lake Petén Itzá was drilled by the International Continental Scientific Drilling Program (ICDP), obtaining seven lacustrine sediment records: PI-01, PI-02, PI-03, PI-04, PI-06, PI-07, and PI-09. Here, we present data from Site PI-1 (16.99951°N, -89.79566°W), located in the northern part of the lake. At the Continental Scientific Drilling Facility at the University of Minnesota, bulk density was analyzed using a GEOTEK multi-sensor core logger with gamma-ray attenuation, with measurements taken every 0.5 cm. Inorganic geochemistry data were obtained using X-ray fluorescence (XRF) with a Cox Analytical Itrax Core Scanner. Cores from PI-1 were measured with a Cr-tube at 30 kV, 55 mA, 15-second exposure, at 1-cm resolution. XRF data are presented in counts per second (cps). Subsequently, data were transformed to centered log-ratio (CLR). CLR values were obtained by dividing each element's concentration by the geometric mean of the elements measured at the same depth, then taking the natural logarithm of the ratio. CLR results have no units. Pollen data include new data from Site PI-1 (189 samples) presented by Martínez-Abarca et al. (2024). For each sample, pollen abundances were converted into percentages of the pollen sum. A \"tropicality index\" was calculated as ln(Moraceae% + 1) / ln(Quercus% + Pinus% + 1). Bulk organic geochemistry includes measurements of total carbon (TC) and total nitrogen (TN) using a Carlo Erba NA1500 CNS analyzer. Total inorganic carbon (TIC) was measured coulometrically using a UIC (Coulometrics) 5014 CO2 coulometer coupled with an AutoMate Carbonate Preparation Device, with approximately 15 mg of sample used for analysis. Total organic carbon (TOC) was calculated by subtracting TIC from TC. TOC/TN ratios were calculated on a molar basis. Depth data correspond to the \"Core composite depth below lake floor (CCLF)\" or \"Master composite depth (MCD)\", which accounts for core recovery gaps and depth inconsistencies, while age data are based on the age-depth models presented by Martínez-Abarca et al. (2024).本研究呈现佩滕伊察湖（Lake Petén Itzá）的沉积物容重（bulk density）、无机地球化学数据（涵盖Ti、Ca、Al、Mn及Fe）、孢粉数据（涵盖栎属Quercus、桑科Moraceae、松属Pinus及热带性指数（tropicality index）），以及沉积物地球化学数据（涵盖总有机碳（TOC）、总氮（TN）、总有机碳与总氮比值（TOC/TN））。2006年，国际大陆科学钻探计划（ICDP）对佩滕伊察湖开展钻探作业，获取了7套湖相沉积记录：PI-01、PI-02、PI-03、PI-04、PI-06、PI-07及PI-09。本研究聚焦该湖北部的PI-1岩心位点（北纬16.99951°，西经89.79566°）并呈现其相关数据。在明尼苏达大学大陆科学钻探实验室，采用搭载伽马射线衰减模块的GEOTEK多传感器岩心记录仪对容重进行分析，测量间隔设置为0.5厘米。无机地球化学数据通过X射线荧光光谱法（XRF）结合Cox Analytical Itrax岩心扫描仪获取。PI-1岩心采用铬靶管（Cr-tube）进行测试，测试参数为30千伏、55毫安、曝光时长15秒，空间分辨率为1厘米。XRF数据以每秒计数（cps）为单位呈现，随后经中心化对数比（CLR）转换处理：将同一深度下各元素的浓度除以该深度所有被测元素的几何平均值，再对所得比值取自然对数，最终得到的CLR结果无单位。孢粉数据包含Martínez-Abarca等人（2024）发表的PI-1位点新数据，共计189个样品。每个样品的孢粉浓度均转换为孢粉总浓度的百分比，本研究构建的热带性指数计算公式为：ln(桑科百分比+1)/ln(栎属百分比+松属百分比+1)。沉积物块状有机地球化学测试涵盖总碳（TC）与总氮（TN），采用Carlo Erba NA1500 CNS元素分析仪完成。总无机碳（TIC）采用库仑法测试：使用UIC（Coulometrics）5014型CO₂库仑计并配套AutoMate碳酸盐制备装置，每份样品的测试用量约为15毫克。总有机碳（TOC）通过总碳（TC）减去总无机碳（TIC）计算得到，TOC/TN比值以摩尔比进行计算。深度数据采用"湖床下方岩心复合深度（CCLF）"或"标准复合深度（MCD）"，该深度体系可校正岩心获取过程中的缺失段与深度不一致问题；年代数据则基于Martínez-Abarca等人（2024）提出的年代-深度模型。