ALBERT

Description: Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Continental Shelf Research 27 (2007): 375-399, doi:10.1016/j.csr.2005.07.008.

Description: A mooring and tripod array was deployed from the fall of 2002 through the spring of 2003 on the Po prodelta to measure sediment transport processes associated with sediment delivered from the Po River. Observations on the prodelta revealed wave-supported gravity flows of high concentration mud suspensions that are dynamically and kinematically similar to those observed on the Eel shelf (Traykovski et al., 2000). Due to the dynamic similarity between the two sites, a simple one-dimensional across-shelf model with the appropriate bottom boundary condition was used to examine fluxes associated with this transport mechanism at both locations. To calculate the sediment concentrations associated with the wave-dominated and wave-current resuspension, a bottom boundary condition using a reference concentration was combined with an “active layer” formulation to limit the amount of sediment in suspension. Whereas the wave-supported gravity flow mechanism dominates the transport on the Eel shelf, on the Po prodelta flux due to this mechanism is equal in magnitude to transport due to wave resuspension and wind-forced mean currents in cross-shore direction. Southward transport due to wave resuspension and wind forced mean currents move an order of magnitude more sediment along-shore than the downslope flux associated wave-supported gravity flows.

Description: This work funded by the U.S. Office of Naval Research under grant number #N00014-02-10378, under the direction of program manager, Tom Drake.

Description: Changes in the concentrations of major, some minor and trace elements occurring in both surface and groundwater of the lower Jordan River–Dead Sea drainage basin have been investigated in order to identify the characteristics of the regional aquifers and their recharge areas. Spider patterns of elements and rare earth distribution patterns pinpoint the characteristic chemical features of groundwater. As compared to seawater, the high Br/Cl ratios in groundwater are caused either by high Br/Cl ratios in precipitation, by leaching of Br from bituminous matter or by mixing with brines beyond the epsomite stage. The locations of groundwater samples with enhanced B contents coincide with the distribution of gypsum in the beds of the Lisan Formation, which produces water with nearly constant B/SO42− molar ratios. Aeolian distribution of the unconsolidated Lisan sediments influences the B/SO4 ratio in the area of Lake Tiberias and in the Jordan Highlands. The high Gd anomaly in the Dead Sea water is of geologic origin whereas that in the Jordan River and in Nahal (stream) Qidron is largely anthropogenic. The anthropogenic Gd input to the Dead Sea is insignificant compared to the actual amount in the water of the Dead Sea. Hot saline water encountered along the western shores of the Dead Sea with high Gd anomalies indicate that they contain large amounts of ancient Dead Sea water that mix (as hot ascending brines) with fresh water. The recharge area of groundwater in the lower Jordan Valley extends largely over limestone and dolomite outcrops of the Upper Cretaceous Judea Group. Weathering of locally underlying Lower Cretaceous volcanics in the area of Pezael–Beqaot, and Argaman yield groundwater with δ34S(SO42−) values ranging from − 2 to + 4‰. The presence of sulphide-bearing bodies in this area is attested to magnetic anomalies detected at depths of several kilometres. δ34S(SO42−) indicates very deep groundwater circulation. High δ34S(SO42−) 〉 15‰ is typical for marine sulphates from the Judea and Avedat Group limestone. The springs located along the northwestern shore of the Dead Sea discharge water replenished on the eastern Judea Mountains. The increase in the salinity of this water is due to brines flushed from sediments and from adjacent sedimentary rocks, which host entrapped brines from the precursors of the Dead Sea formed during the late stages of Lake Lisan. Fresher water flushes out these residual brines as a result of falling sea level. Salinity increase in groundwater is also affected by the ascent of deep-seated hot brines from pre-Sedom periods along the Rift faults. Calculations of mixing between fresh and highly saline end-members show that leaching of anhydrite from sediments, precipitation of calcite, formation of dolomite, albitization of plagioclase and ion exchange with abundant clay minerals control the major-element composition of the saline groundwater.