Polarity chron boundaries and foraminiferal 87Sr/86Sr ratios of ODP Sites 162-986 and 162-987

Cores recovered at Sites 986 and 987 comprise glacial fan sedimentation associated with the Svalbard-Barents Sea and Greenland Ice Sheets, respectively. At Site 986, the top 150 m and the basal 250 m yielded interpretable magnetic stratigraphies. The record from the intervening 550 m is compromised by drilling-related core deformation, poor recovery, and numerous debris flows. The uppermost 150 m appears to record the Brunhes/Matuyama boundary and the Jaramillo Subchron. The base of the drilled section (at ~950 meters below seafloor [mbsf]) is interpreted to lie within the Matuyama Chron (age <2.58 Ma) with an apparent normal polarity interval in the ~730-750 mbsf interval. Dinoflagellate cyst biostratigraphy and Sr isotopic ratios are consistent with a Matuyama age for the base of the drilled section and with the normal polarity interval as the Olduvai Subchron. On the other hand, the last occurrence of Neogloboquadrina atlantica (sinistral) and the last common occurrence of the warm-dwelling Globigerina bulloides at 647-650 mbsf in Hole 986D indicate an age for this level of ~2.3 Ma, inconsistent with the designation of the Olduvai Subchron in the ~730-750 mbsf interval. If the age at 647-650 mbsf in Hole 986D is taken as 2.3 Ma and the base of the hole lies within the Matuyama Chron, then the sedimentation rate in the basal 300 m of the cored section averages 1 m/k.y. At Site 987, the magnetic stratigraphy is fairly unambiguous throughout the section and yields an age of 7.5 Ma (Chron 4n) for the base of the drilled section. The paucity of calcareous and siliceous microfossils precludes biostratigraphic corroboration of the magnetostratigraphic interpretation, although dinoflagellate cysts provide general support, particularly at the base of the section. The age model indicates relatively low sedimentation rates (~5 cm/k.y.) at the base of the section with rates at least four to five times greater during intervals of debris flows at ~5-4.6 and ~2.6 Ma.

(Table 2) Revised stacked record on magnetic susceptibility of ODP Site 162-984 sediments

Magnetic field and susceptibility data were collected using the geological high-resolution magnetometer tool string (GHMT) at three sites during Ocean Drilling Program Leg 162. Postcruise processing of the magnetic field data yielded a polarity stratigraphy for Holes 986C and 987E. A magnetic susceptibility record was measured at Hole 984B. Detailed analysis of the core and log susceptibility records at Hole 984B yielded an empirical tool resolution of the susceptibility measurement tool (SUMT) of 53 cm. At Site 984, where sedimentation rates were typically >10 cm/k.y., this gave a resolution of at least ~5000 yr. This data report summarizes the GHMT postcruise processing, method of interpretation, and analysis of the SUMT resolution.

(Table 1) Helium and Thorium 230 excess concentrations in sediment cores B18 and B25

At four sites in the central equatorial Pacific Ocean the flux of extraterrestrial 3He, determined using the excess 230Th profiling method, is 8 * 10**-13 cm**3 STP/cm**2/ka. This supply rate is constant to within 30%. At these same sites, however, the burial rate of 3He, determined using chronostratigraphic accumulation rates, varies by more than a factor of 3. The lowest burial rates, which occur north of the equator at 1°N, 139°W are lower than the global average rate of supply of extraterrestrial 3He by 20% and indicate that sediment winnowing may have occurred. The highest burial rates, which are recorded at the equator and at 2°S, are higher than the rate of supply of extraterrestrial 3He by 100%, and these provide evidence for sediment focusing. By analyzing several proxies measured in core PC72 sediments spanning the past 450 kyr we demonstrate that periods of maximum burial rates of 230Th, 3He, 10Be, Ti, and barite, with a maximum peak-to-trough amplitude of a factor of 6, take place systematically during glacial time. However, the ratio of any one proxy to another is constant to within 30% over the entire length of the records. Given that each proxy represents a different source (234U decay in seawater, interplanetary dust, upper atmosphere, continental dust, or upper ocean), our preferred interpretation for the covariation is that the climate-related changes in burial rates are driven by changes in sediment focusing.

Benefits and Effects of Interactive Gaming Exercise as Compared to Traditional Exercise Techniques: An Investigation of the Relationship Between Physical Activity Levels and Mode of Activity in College Students

Gemstone Team F.I.T.N.E.S.S. (Fun Interactive Techniques for New Exercise and Sport Styles)