Mineralogical and geochemical composition of the weathering profile from the Mulanxi catchment

This dataset reported the mineralogical and geochemical composition of the weathering profile (~ 30 m) from the Mulanxi catchment. The sampling location is located in Xianyou County, Putian City, Fujian Province, approximately 50 km inland from the East China Sea (118°44.694′E, 25°21.853′N). The region experiences a subtropical monsoon climate, characterized by warm, humid summers from June to August and mild, relatively dry winters from December to February. The bedrock is a white-colored leucogranite, with a SiO₂ concentration of approximately 76%, and contains virtually no dark minerals, as confirmed by XRD analysis. The dominant minerals in the unaltered, hard bedrock are K-feldspar, albite, and quartz. Above a depth of ~22 meters, no primary minerals except quartz were detectable in the bulk regolith, as evidenced by XRD. Kaolinite, and to a lesser extent illite, are the dominant secondary minerals present. Specifically, we reported Mg isotope composition of the bulk composition, clay-sized fraction and exchangeable fraction of the regolith sediments at most depths. We found that kaolinite preferentially incorporates light Mg isotopes and illite preferentially incorporates heavy isotopes. Table S1 Mg isotope composition of bulk regolith, clay-sized fraction, and exchangeable fraction in the weathering profile from the Mulanxi catchment. Table S2 Mineralogical composition of bulk regolith and clay-sized fraction in the weathering profile from the Mulanxi catchment. Table S3 Major and trace element composition of bulk regolith and clay-sized fraction in the weathering profile from the Mulanxi catchment.本数据集记录了木兰溪流域（Mulanxi catchment）一处约30米深风化剖面的矿物学与地球化学组成。采样点位于福建省莆田市仙游县，地处东海内陆约50公里处，地理坐标为118°44.694′E，25°21.853′N。 该区域属亚热带季风气候，夏季（6月至8月）温暖湿润，冬季（12月至2月）温和偏干燥。 基岩为白色淡色花岗岩（leucogranite），二氧化硅（SiO₂）含量约76%，经X射线衍射（X-ray Diffraction，XRD）分析确认几乎不含暗色矿物。未蚀变硬基岩中的主要矿物为钾长石、钠长石与石英。在约22米以上深度的全量风化壳中，X射线衍射分析仅检出石英一种原生矿物；次生矿物以高岭石为主，伊利石次之。 本研究同时测定了多数深度下风化壳沉积物的全量组分、粘粒级组分（clay-sized fraction）与可交换态组分（exchangeable fraction）的镁同位素（Mg isotope）组成。结果显示，高岭石优先富集轻镁同位素，而伊利石则优先富集重镁同位素。 表S1 木兰溪流域风化剖面全量风化壳、粘粒级组分与可交换态组分的镁同位素组成 表S2 木兰溪流域风化剖面全量风化壳与粘粒级组分的矿物组成 表S3 木兰溪流域风化剖面全量风化壳与粘粒级组分的主量与微量元素组成