Corrected index properties for ODP Leg 127 and 128 sites

During Legs 127 and 128, we found a systematic error in the index property measurements, in that the wet bulk density, grain density, and porosity did not satisfy well-established interrelationships. We have found that an almost constant difference exists between the weight of water lost during drying and the volume of water lost. This discrepancy is independent of volume or water content of the sample. The water losses should be equal because the density of water is close to 1.0 g/cm**3. The pycnometer wet volume measurement has been identified as the source of the systematic error. The wet volume on average is 0.2 cm**3 too low. For the rare cases when the water content is negligible, there is no offset. The source of the wet volume error results from the partial vapor pressure of water in the pycnometer cell. Newly corrected tables of index properties measured during Legs 127 and 128 are included. The corrected index properties are internally consistent. The data are in better agreement with theoretical models that relate the index properties to other physical properties, such as thermal conductivity and acoustic velocity. In future, a standard volume sampler should be used, or the wet volume should be calculated from the dry volume and the water loss by weight.在Legs 127与128航次执行期间，我们在物性指标（index property）测量工作中发现了一处系统误差，具体表现为湿松密度（wet bulk density）、颗粒密度（grain density）与孔隙率（porosity）未符合学界公认的相互关联规律。我们观测到，干燥过程中损失的水的质量与损失的水的体积之间始终存在近乎恒定的差值。该偏差与样品的体积或含水量均无关联。由于水的密度近似为1.0 g/cm³，理论上二者的损失量应当完全相等。经溯源，该系统误差的根源为比重瓶（pycnometer）的湿体积测量环节：湿体积的测量值平均偏低0.2 cm³。仅在含水量可忽略不计的极少数场景中，不存在该测量偏差。该湿体积测量误差的成因是比重瓶腔体内水的分蒸气压效应。本数据集包含经重新校正后的Legs 127与128航次物性指标测量数据表。校正后的物性指标数据内部具备一致性，且与将物性指标与热导率（thermal conductivity）、声速（acoustic velocity）等其他物理性质相关联的理论模型吻合度更高。后续工作中，应采用标准体积采样器，或通过干体积与质量法测得的失水率计算湿体积。