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.

Long chain diol index and paleotemperature reconstruction for IODP Hole 306-U1313C

Recently, a new organic geochemical paleothermometer based on the relative abundance of long chain alkyl 1,13- and 1,15-diols, the so-called long chain diol index (LDI), was proposed. Because of its novelty, the proxy has not been reported for sediments older than 43 ka. We therefore determined the LDI for 14 sediment samples from the early Pleistocene between 2.49 and 2.41 Ma, comprising Marine Isotope Stage (MIS) 98 to 95, and converted the values to sea surface temperature (SST) estimates to test whether the LDI could be applied or not to the early Quaternary. We show that the long chain diols can be preserved in marine sediments from the early Pleistocene, although at our study site this is limited to periods of increased biomarker accumulation (glacials). Although the results are based on a limited time interval and number of samples, the similarity between LDI-based SST and alkenone-based SST from the same samples suggests that the LDI proxy may have potential for studies covering the entire Quaternary.

Calcium carbonate, organic carbon, sediment description and hydrogen and oxygen index at DSDP Sites 93-603, 93-605, 93-604 and 95-603

The organic matter contents of sediments and rocks sampled during DSDP Leg 93 have been characterized by CHN and Rock-Eval analyses. Most samples from Sites 604 and 605 on the New Jersey continental slope and from Site 603 on the Hatteras outer continental rise contained less than 0.5% organic carbon. Some Neogene samples from the slope contained 1 to 2% organic carbon, and Cretaceous samples from the outer rise were as rich as 13.6% organic carbon by weight. Thin layers of black claystones of Santonian, Cenomanian, and Albian age were found interbedded in organiccarbon- lean, bioturbated, turbiditic claystones. Similar layers of turbiditic black marlstones were interspersed among Neocomian limestones and sandstones. Although the organic matter in many of the samples appeared to be detrital continental material, according to Rock-Eval and C/N values, Cenomanian black shales, in particular, contained substantial proportions of marine-derived organic matter.