East Antarctic sediment carbonate mineralogy, 2020

Marine sediments often represent an important reservoir of carbonate minerals that will react rapidly to changing seawater chemistry as a result of ocean acidification. Ocean acidification (the reaction of CO2 with seawater) lowers the saturation state with respect to carbonate minerals and may lead to dissolution of these minerals if undersaturation occurs.
There are three main carbonate minerals found in marine sediments:
1. aragonite
2. calcite (also referred to as low-magnesium calcite, containing less than 4mol% MgCO3)
3. high-magnesium calcite (greater than 4 mol% MgCO3)
Due to the different structure of these minerals, they have different solubilities with high-Mg calcite the most soluble, followed by aragonite and then calcite. As seawater CO2 increases and the saturation state with respect to carbonate minerals decreases, high-Mg calcite will be the first mineral subject to undersaturation and dissolution.
By measuring the carbonate mineral composition of sediments, we can determine which areas are most at risk from dissolution. This information forms an important baseline with which we can assess future climate change. The effect of ocean acidification on carbonates in marine sediments will occur around the world, but due to the lower seawater temperatures in Antarctica, solubility is much lower so the impacts will occur here first.

This dataset is a compilation of carbonate mineralogy data from surface sediments collected from the East Antarctic margin. The dataset includes sample metadata, bulk carbonate content, %calcite, % aragonite and mol% MgCO3 (i.e. the magnesium content of high-Mg calcite). This dataset was compiled from new (up to 2020) and archived sediment samples that contacted sufficient carbonates (typically greater than 3% CaCO3)/

海洋沉积物通常是碳酸盐矿物的重要储库，这些矿物会因海洋酸化导致的海水化学性质变化而快速发生反应。海洋酸化（即CO₂与海水的反应）会降低碳酸盐矿物的饱和状态，若出现不饱和状态，则可能导致这些矿物溶解。

海洋沉积物中存在三种主要的碳酸盐矿物：
1. 文石（aragonite）
2. 方解石（calcite，也称为低镁方解石，含MgCO₃低于4mol%）
3. 高镁方解石（high-magnesium calcite，含MgCO₃高于4mol%）

由于这些矿物的结构不同，它们的溶解度也各异，其中高镁方解石溶解度最高，其次是文石，最后是方解石。

通过测量沉积物中的碳酸盐矿物组成，我们可以确定哪些区域最易受到溶解风险的影响。这些信息构成了评估未来气候变化的重要基线。海洋酸化对海洋沉积物中碳酸盐的影响将在全球范围内发生，但由于南极海水温度较低，碳酸盐矿物的溶解度更低，因此这些影响将首先在此处显现。

本数据集汇编了从南极东部边缘采集的表层沉积物中的碳酸盐矿物学数据。数据集包含样品元数据、总碳酸盐含量、方解石百分比、文石百分比以及MgCO₃摩尔百分比（即高镁方解石中的镁含量）。该数据集由2020年及之前的新样品和存档沉积物样品汇编而成，这些样品含有足够的碳酸盐（通常CaCO₃含量高于3%）。