Showing papers by "Christine Hatté published in 2012"
TL;DR: The Shi'bat Dihya 1 site in western Yemen, dated by optically stimulated lu-minescence to 55 ka, provides insight into the Middle Paleolithic peopling of the Arabian Peninsula as discussed by the authors.
Abstract: The Shi'bat Dihya 1 site in western Yemen, dated by optically stimulated lu-minescence to 55 ka, provides insight into the Middle Paleolithic peopling of the Arabian Peninsula. The archaeological layer is interstratified within thick, sandy silt floodplain deposits filling a piedmont basin. Luminescence dates, lack of soil development, and gypsum precipitation indicate a high accretion rate of the floodplain during Marine Isotope Stage 3, in connection with a (semi)-arid environment. Rapid overbank sedimentation was likely a result of the remo-bilization of loess material deposited on the Yemeni Great Escarpment at the periphery of the adjacent Tihama coastal sand desert or of other sources. Fabric and size analyses of the lithic artifacts, together with spatial projections, indicate site modifications by floods. Primary modifications include (1) selective accumulation of medium-sized lithic pieces as a result of hydraulic sorting, (2) bimodal orientation of artifacts, and (3) ripple-like arrangement of lithics and bone/tooth fragments. The overrepresentation of teeth may also be a consequence of sorting. Although floods have distorted the original site patterning, long-distance transport of artifacts by water can be excluded, as indicated by relatively high refitting rate, close proximity of artifacts derived from the same block of raw material, and lack of abrasion of the pieces. Therefore, the site is considered " geologically " in situ because its remobilization by water occurred shortly after human abandonment. This study also stresses that the effective preservation of a site cannot be assessed without careful taphonomic study, even in a potentially favorable depositional context such as silty alluvium. C 2012 Wiley Periodicals, Inc.
34 citations
TL;DR: The MAIDENiso model as mentioned in this paper is a new version of the process-based biogeochemical model for tree growth, which has been implemented to simulate stable oxygen and carbon isotopes in tree-ring cellulose.
Abstract: MAIDENiso is a new version of the process-based biogeochemical model MAIDEN of tree growth. Isotopic modules have been implemented to simulate stable oxygen and carbon isotopes in tree-ring cellulose (TRC). In addition to annual increment biomass, this new model version estimates d 18 O and d 13 C associated with the daily amount of carbon allo- cated to the stem. MAIDENiso only requires daily input data: minimal and maximal air temperatures, amount of precipita- tion, CO2 atmospheric concentration, and d 13 Ci n CO2. MAIDENiso simulates tree-ring width, d 18 O in precipitation (d 18 OP), d 18 O in soil water (d 18 OSW), d 18 O in xylem water (d 18 OXW), d 18 O in cellulose (d 18 OTRC), and d 13 C in cellulose (d 13 CTRC). The model has been calibrated and validated with tree-ring series sampled in the Fontainebleau Forest (France) from 1953 to 2000. We first calibrated several parameters for the 1977-2000 period and then validated it for the independent 1953- 1976 period. Over the complete interval (1953-2000), we obtained correlations between observations and simulations above 0.5 for both isotopic series and above 0.65 for tree growth series. An important feature of the model is its ability to simulate not only extreme values of tree growth, such as the effect of 1976 drought, but also its persistence over several years. Resume : MAIDENiso est une nouvelle version du modele MAIDEN des processus biogeochimiques de la croissance d'ar- bres. Des modules isotopiques ont ete ajoutes a ce dernier pour simuler les isotopes stables de l'oxygene et du carbone de
26 citations