Inside the "African Cattle Complex": Animal Burials in the Holocene Central Sahara

Cattle pastoralism is an important trait of African cultures. Ethnographic studies describe the central role played by domestic cattle within many societies, highlighting its social and ideological values well beyond its mere function as 'walking larder'. Historical depth of this African legacy has been repeatedly assessed in an archaeological perspective, mostly emphasizing a continental vision. Nevertheless, in- depth site-specific studies, with a few exceptions, are lacking. Despite the long tradition of a multi-disciplinary approach to the analysis of pastoral systems in Africa, rarely do early and middle Holocene archaeological contexts feature in the same area the combination of settlement, ceremonial and rock art features so as to be multi- dimensionally explored: the Messak plateau in the Libyan central Sahara represents an outstanding exception. Known for its rich Pleistocene occupation and abundant Holocene rock art, the region, through our research, has also shown to preserve the material evidence of a complex ritual dated to the Middle Pastoral (6080-5120 BP or 5200-3800 BC). This was centred on the frequent deposition in stone monuments of disarticulated animal remains, mostly cattle. Animal burials are known also from other African contexts, but regional extent of the phenomenon, state of preservation of monuments, and associated rock art makes the Messak case unique. GIS analysis, excavation data, radiocarbon dating, zooarchaeological and isotopic (Sr, C, O) analyses of animal remains and botanical data are used to explore this highly formalized ritual and lifestyles of a pastoral community in the Holocene Sahara

Strontium isotope ratios in stream base flow within the Georgia Piedmont province

Strontium isotope ratios, strontium ion concentrations, major ion concentrations, and stream discharge were measured within the Middle Oconee River basin upstream of Arcade, Georgia during the period 2003- 2004. Strontium isotope ratios (87Sr/86Sr) in stream base flow were between 0.7126 and 0.7172, considerably higher than rainfall (0.7117) and shallow ground water (0.7120). This indicates that Sr and by inference other weathering products in base flow are derived principally from weathering, rather than ion exchange in the shallow soil zone. Unlike all other parameters, strontium isotope ratios were temporally invariant within a given watershed, independent of seasonal variations with respect to base flow discharge. Strontium isotope ratios were significantly different in all four watersheds and therefore provide the best geochemical “tracer” for base flow. 87Sr/86Sr ratios increased as a function of basin area, independent of Sr ion concentrations, probably as the result of the increased contribution from rubidium-bearing minerals such as K-feldspar, muscovite, and biotite.Sponsored by: Georgia Environmental Protection Division U.S. Geological Survey, Georgia Water Science Center U.S. Department of Agriculture, Natural Resources Conservation Service Georgia Institute of Technology, Georgia Water Resources Institute The University of Georgia, Water Resources Facult

Rb-Sr whole rock ages of Silurian-Devonian volcanics from eastern Maine

in Shorter Contributions to Maine Geology: Maine Geological Survey (Department of Economic Development), Bulletin 23, p. 49-52.https://digitalmaine.com/mgs_publications/1140/thumbnail.jp

(Table T1) Pore-water strontium content, and Sr isotope composition and ages of pore waters and sedimentary carbonates of ODP Leg 171B sites

Strontium concentrations and 87Sr/86Sr values were measured on pore-water and sedimentary carbonate samples from sediments recovered at Sites 1049-1053 on the Blake Spur during Ocean Drilling Program Leg 171B. These sites form a 40-km-long depth transect extending along the crest of the Blake Spur from near the upper edge of the Blake Escarpment (a steep cliff composed of Mesozoic carbonates) westward toward the interior of the Blake-Bahama Platform. Although these sites were selected for paleoceanographic purposes, they also form a hydrologic transect across the upper eastern flank of the Blake-Bahama Platform. Here, we use pore-water strontium concentrations and isotopes as a proxy to define patterns of fluid movement through the flanks of this platform. Pore-water strontium concentration increases with depth at all sites implying that strontium has been added during sediment burial and diagenesis. The isotopic values decrease from seawater-like values in the shallow samples (~0.70913) to values as low as 0.707342 in one of the deepest samples (~625 meters below seafloor). The change in pore-water strontium isotopic values is independent of the strontium isotopic compositions predicted from the host sediment age and measured on bulk carbonate in some samples. In most cases the difference between predicted sediment strontium isotopic composition and measured value is less than ±2 about the mean of the measured strontium value. Both the increase in concentration and the decrease in the strontium isotope values with increasing depth indicate that strontium was expelled from older carbonates. The strontium concentration and isotope profiles vary between sites according to their proximity to the Blake-Bahama Platform edge. Profiles from Site 1049 (nearest the platform edge) show the greatest amount of mixing with modern seawater, whereas the site most distal to the platform edge (Site 1052) shows the most significant influence of older, deeper carbonates on the pore-water strontium isotopic composition

(Table 1) 87Sr/86Sr results for the Cretaceous-Tertiary boundary, ODP Hole 171-1049C

Previous studies of 87Sr/86Sr patterns across the Cretaceous-Tertiary (K-T) boundary have generated inconsistent results. Analyses of samples from Ocean Drilling Program Hole 1049C provide better taphonomic and diagenetic control than has been previously achieved and indicate (1) that there was a rapid increase of ~0.000030 in seawater 87Sr/ 86Sr ratios across the K-T boundary, (2) that post K-T Cretaceous foraminifera at this site are reworked, and (3) that subtle diagenetic overprinting affects the basal ~15 cm of the Danian ooze. These conclusions are consistent with the asteroid impact hypothesis. Reworking rather than survivorship confirms nearly complete extinction of Cretaceous Tethyan planktic foraminifera; the 87Sr/86Sr excursion can be explained by enhanced continental weathering, perhaps related to acid rain in the aftermath of the K-T impact

87Sr/86Sr results for the Maastrichtian samples from ODP Leg 171

Analyses of 87Sr/86Sr in foraminifera and sedimentological observations suggest that the Chicxulub impact was not the trigger for slumps or a hiatus within the Maastrichtian section recovered at Ocean Drilling Program Sites 1049, 1050, and 1052 (subtropical western North Atlantic). The slumps and hiatus occur within a sequence dominated by pelagic chalk. The 87Sr/86Sr measurements show a general increase through the Maastrichtian at each site, but suggest chronostratigraphic gaps on the order of 10 Myr across the slumps. Some of the slumps have burrowed upper surfaces and are composed of material that is older and coarser grained than the bounding chalks. Pelagic deposition punctuated by gravity flows easily explains the Maastrichtian record on Blake Nose, whereas an impact-based explanation for slumping is difficult to reconcile with sedimentological and geochemical observations