Estimates of late Early Cretaceous atmospheric CO2 from Mongolia based on stomatal and isotopic analysis of Pseudotorellia

Our dataset includes 115 leaf cuticles related to two species of Pseudotorellia Florin from three stratigraphically similar samples at the Tevshiin Govi lignite mine in central Mongolia (~119.7–100.5 Ma, Aptian–Albian, Cretaceous). We apply a well-vetted paleo-CO2 proxy based on leaf gas-exchange principles (the Franks model) to those leaves for paleo-CO2 reconstruction, which requires leaf stomata and carbon isotope analysis. All cuticle measurements are summarized in this dataset. , The leaves studied here are from the Tevshiingovi lignite mine in central Mongolia, approximately 220 km south-southwest of Ulaanbaatar. We excavated lignite blocks from three stratigraphically similar samples from lignite #2 along the Tevshiin Govi lignite mine wall. The blocks were disaggregated with detergent, 3% hydrogen peroxide, and deionized water. Because chemical treatments can affect δ13C measurements (Barral et al., 2015), we measured one leaf (cut in half) both with and without peroxide treatment and found an isotopic difference of 0.22 ‰, which propagates to a small change in estimated CO2 (~2.6 %). The lithological column was illustrated using SDAR package version 0.9-55 (Ortiz and Jaramillo, 2020).
Leaves were first cut in half, with one half set aside for isotope analysis. The remaining half was cleared following standard practices (Dilcher, 1974; Wang, 2010; Liang et al., 2022). Fragments were soaked in deionized H2O (dH2O) for 1 hour. Softened leaf fragments were cut a..., , # Data from: Estimates of late Early Cretaceous atmospheric CO2 from Mongolia based on stomatal and isotopic analysis of Pseudotorellia

[https://doi.org/10.5061/dryad.g1jwstqzv](https://doi.org/10.5061/dryad.g1jwstqzv)

This dataset is the Appendix S2 for a manuscript (\"AJB-S-24-00018\") in the American Journal of Botany, entitled \"Estimates of late Early Cretaceous atmospheric CO2 from Mongolia based on stomatal and isotopic analysis of *Pseudotorellia*\". This dataset is collected from two species of *Pseudotorellia* Florin from three stratigraphically similar samples at the Tevshiin Govi lignite mine in central Mongolia (~119.7–100.5 Ma) for a paleo-CO2 proxy based on leaf gas-exchange principles (the Franks model).

## Description of the data and file structure

All data, including fossil leaf stomatal measurements and carbon isotope analysis, are listed in an Excel spreadsheet. For each leaf fragment, we measured stomatal density based on 4 field-of-view, which mostly at 100× (0.80...

本数据集包含115份叶角质层标本，均采自蒙古国中部特夫欣戈维（Tevshiin Govi）褐煤矿的3件地层相似样品，对应拟松型叶属（Pseudotorellia Florin）的两个物种，地质年代为白垩纪阿普第期至阿尔布期（约119.7~100.5 Ma）。本研究基于叶片气体交换原理构建的经严格验证的古大气CO₂代用指标（弗兰克斯模型，Franks model），对这些化石叶片开展古CO₂重建工作，该方法需结合叶片气孔分析与碳同位素分析。本数据集汇总了所有角质层测量数据。

本次研究的化石叶片采自蒙古国中部特夫欣戈维褐煤矿，该矿位于乌兰巴托西南偏南约220公里处。我们从特夫欣戈维褐煤矿2号褐煤层的矿壁处，采集了3件地层相似的褐煤块体。随后使用洗涤剂、3%过氧化氢与去离子水对煤块进行解离处理。由于化学处理可能会影响δ¹³C（碳同位素比值）的测量结果（Barral等，2015），我们对1片对半切开的叶片分别开展过氧化氢处理与未处理的对照测量，测得同位素差值为0.22‰，该差值对应古CO₂估算值产生约2.6%的小幅变化。本研究的岩性柱图由SDAR软件包（版本0.9-55，Ortiz和Jaramillo，2020）绘制完成。

首先将叶片对半切开，其中一半留存用于同位素分析。剩余的另一半则按照标准流程进行解离处理（Dilcher，1974；Wang，2010；Liang等，2022）。将叶片碎片置于去离子水（dH₂O）中浸泡1小时。软化后的叶片碎片被切割为……

# 数据来源：基于蒙古国拟松型叶属气孔与同位素分析的早白垩世晚期大气CO₂估算

[https://doi.org/10.5061/dryad.g1jwstqzv](https://doi.org/10.5061/dryad.g1jwstqzv)

本数据集为发表于《美国植物学杂志》（American Journal of Botany）的稿件（编号"AJB-S-24-00018"）的附录S2，论文标题为《基于蒙古国拟松型叶属气孔与同位素分析的早白垩世晚期大气CO₂估算》。本数据集的标本采自蒙古国中部特夫欣戈维褐煤矿的3件地层相似样品，对应拟松型叶属（Pseudotorellia Florin）的两个物种，地质年代约为119.7~100.5 Ma，用于构建基于叶片气体交换原理的古大气CO₂代用指标（弗兰克斯模型，Franks model）。

## 数据与文件结构说明

所有数据（包括化石叶片气孔测量数据与碳同位素分析数据）均汇总于一份Excel电子表格中。针对每一片叶片碎片，我们基于4个视域开展气孔密度测量，其中多数视域放大倍数为100×（0.80……）