Thunderstorms on Jupiter

The presence of a considerable acetylene concentration on Jupiter, despite the fast rate of its photolytic hydrogenation, provides strong evidence for the operation of frequent and powerful thunderstorms in the Jovian atmosphere. Whereas acetylene regeneration can occur only during thunderstorms, the photolytically destroyed ammonia can be regenerated both in thunderstorms and in the low and hot atmospheric levels. A rate of Earthlike lightning strokes 10⁴ times larger than on Earth is inferred from the calculated rate of acetylene's photolytic destruction. The rate of acetylene production by thunder shock waves and the products obtained from its photolytic hydrogenation can account for the large ethane concentration and the absence of ethylene. The yellow-brown acetylene polymer and the ruby-red polymers, obtained from thunder-produced hydrogen cyanide or cyanogen with ammonia, are likely contributor to the Jovian coloration.     

Structure-controlled groundwater flow and salinization paths in the Bet She’an and Harod Valleys,Israel

The Bet She’an and Harod Valleys are regional recipients and mixing zones for groundwater draining to these valleys from a multiple aquifer system. This aquifer system includes two different carbonate aquifers, several groundwater-bearing basalt flows and deep-seated pressurized brine, the upflow of which causes salinization of fresh groundwater bodies. These aquifers drain through two groups of springs. Due to lack of information on the subsurface structure of the valley the flow-paths of groundwater feeding the springs, the initial distribution of salinities along the valley and particularly, the inflow-paths of the brines, have never been understood but were assumed to be fault-controlled. The interpretation of seismic profiles and analysis of gravity anomalies revealed the subsurface structure of the valley and namely the occurrence of a dense network of faults which branch out from those delineating the Jordan-Dead Sea Rift. The faults formed a series of uplifted and down-warped horst-and-graben structures. By joint analysis of structural, hydrological and geochemical evidence, it occurs that groundwater flow-paths leading to the springs emerging in the middle of the Bet She’an Valley are determined by structural elements such as major faults and fault-controlled structures. The penetration of the pressurized Ca-chloride Rift brines and their inflow into fresh groundwater bodies occurs prevalently along the faults outlining the western margins of the Dead Sea Rift Valley and at their intersection with outbranching NW–SE-striking faults.     

First experimental studies of large samples of gas-laden amorphous “cometary” ices

In a unique machine, the first of its kind, large (200 cm² × 10 cm) samples of gas-laden amorphous ice were prepared at 80 K and 10⁻⁵ Torr. The sample consisted of a fluffy agglomerate of 200-μm ice grains, similar to what is presumed to be the structure of comet nuclei. The sample was heated from above by IR radiation. The properties studied were gas content in the ice and its emanation from the ice upon warming and bearing on the gas/water vapor ratio observed in cometary comae vs this ratio in cometary nuclei and the effect of internal trapped gas on the thermal conductivity of the ice and the density and mechanical properties of pure ice vs gas-laden ice. These findings might have significance for the interpretation of comet observations, the forthcoming ESA’s Rosetta space mission to Comet 46P/Wirtanen in 2012, and to other comet missions.     

Copper mineralization in sedimentary cover associated with tectonic elements and volcanism in Israel

Copper mineralization occurs within the thick Cretaceous to Neogene sedimentary cover of central and northern Israel. Two distinct types of copper-rich anomalies are encountered. One form of copper mineralization is characterized by the presence of copper minerals such as malachite, atacamite, paratacamite, chrysocolla, and/or chalcopyrite forming veins and concretions within the sedimentary host rocks. The second type of copper enrichment is found dispersed within iron oxide veins associated with enrichments of other trace metals such as Ni, V, Zn, Co, Mo, and As. Both forms of copper anomalies lie along and are confined to the vicinity of tectonic elements. These features may be the surface expression of the longitudinal faults of the Dead Sea Rift Valley, of the transverse shear zone of southern and central Negev, or of the EW-trending horsts and grabens of central Israel. In many cases the copper anomalies are found near to or at the contact of volcanic bodies of intermediate to basic composition; in others, they are found in the vicinity of thermal springs. The fault zones may have provided conduits along which solutions, in places possibly briny, could have risen and leached subsurface mineralized volcanic or sedimentary bodies.