IODP Expedition 379 Moisture and Density

Moisture and density (MAD) data were acquired on ~10 mL sediment or rock samples by measuring three out of four material parameters: wet (saturated) mass, wet volume, dry mass, and/or dry volume after 24 h drying in a convection oven at 105 degrees C. From the moisture and volume measurements, the following phase relationships are calculated: wet and dry water content, wet bulk density, dry bulk density, grain density, porosity, and void ratio. The combination of measurements is defined by the submethod chosen: A, B, C, or D. Wet (A, B, or C) and dry (A, B, C, or D) mass is determined using motion-compensated balances. Wet volume is determined either by helium pycnometry (A) or by the sample's geometric dimensions using calipers (A or D). Dry volume (C or D) is measured by helium pycnometry. Submethods A and B are not recommended by IODP. Submethod C is suitable for saturated materials such as fine-grained sediments. Submethod D is suitable for unsaturated porous material such as certain limestones and basalts.含水率与密度（Moisture and Density, MAD）数据的获取流程为：针对约10 mL的沉积物或岩石样品，先在105℃对流烘箱中干燥24小时，随后测量四项材料参数中的三项——湿（饱和）质量、湿体积、干质量及/或干体积。基于含水率与体积的测量结果，可计算得到以下物相关系：湿含水量、干含水量、湿容重（wet bulk density）、干容重（dry bulk density）、颗粒密度（grain density）、孔隙率（porosity）及孔隙比（void ratio）。具体的测量组合由所选子方法（A、B、C或D）决定。湿质量（对应子方法A、B或C）与干质量（对应子方法A、B、C或D）均采用运动补偿天平（motion-compensated balances）进行测定。湿体积的测定方式分为两种：氦比重瓶法（helium pycnometry，仅适用于子方法A），或通过游标卡尺（calipers）测量样品几何尺寸的方法（适用于子方法A或D）。干体积（对应子方法C或D）通过氦比重瓶法测定。子方法A与B未被国际大洋发现计划（Integrated Ocean Drilling Program, IODP）推荐使用。子方法C适用于饱和材料，例如细粒沉积物。子方法D适用于非饱和多孔材料，例如特定石灰岩与玄武岩。