... Science Frontiers ONLINE No. 46: Jul-Aug 1986 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Salt structures on venus?The following quotation is the abstract of a paper appearing in the Bulletin of the American Association of Petroleum Geologists. "The discovery of a surprisingly high deuterium/hydrogen ratio on Venus immediately led to the speculation that Venus may have once had a volume of surface water comparable to that of the terrestrial oceans. We propose that the evaporation of this putative ocean may have yielded residual salt deposits that formed various terrain features depicted in Venera 15 and 16 radar images. "By analogy with models for the total evaporation of terrestrial oceans, evaporite deposits on Venus should be ar least ten to hundreds of meters thick. From ... evidence and insitu chemical analyses, it appears that the salt plains were later buried by lava flows. On Earth, salt diapirism leads to the formation of salt domes, anticlines, and elongated salt intrusions -- features which have dimensions of roughly 1 to 100 km. Due to the rapid erosion of salt by water, surface evaporite landforms are only common in dry regions such as the Zagros Mountains of Iran, where salt plugs and glaciers exist. Venus is far drier than Iran; extruded salt should be preserved, although the high surface temperature (470 C) would probably stimulate rapid salt flow. Venus possesses a variety of circular landforms, ten to hundreds of kilometers wide, which could be either megasalt domes or salt intrusions colonizing impact craters. Additionally, arcuate bands seen in the Maxwell ...
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... is still debated. Here, geophysics merges with biology. Recently, a group of researchers discovered a large (540 square meters) patch of chemosynthetic mussels in a brine-filled pockmark, at a depth of 650 meters, off the Louisiana coast. The mussels grew in a ring around the concentrated brine. The mussels harbor symbionts which consume the methane still seeping up through the brine from a salt diapir (a massive fingerlike intrusion 500 meters below the brine pool. The origin of some diapirs is not well-understood.) The mussels get the oxygen they require from the ordinary seawater covering the dense brine. Like the biological communities surrounding the "black smokers" and other ocean-floor seeps, the brine-filled pockmark community includes several species of shrimp, crabs, and tube ... . We have here another example of the astounding ability of lifeforms to take advantage of unusual, even bizarre niches. (MacDonald, I. Rosman, et al; "Chemosynthetic Mussels at a BrineFilled Pockmark in the Northern Gulf of Mexico," Science, 248:1096, 1990.) Comment. Such examples of life's adaptability are so common one hesitates to label them as anomalous. Yet, one wonders how and why life acquired this property. Is the human urge to go to the planets a genetically derived extension of this urge to colonize new terri tories. From Science Frontiers #73, JAN-FEB 1991 . 1991-2000 William R. Corliss ...
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