MAGELLAN PROJECT OFFICE


P-38169
4/19/91
                         

     This is a full resolution mosaic centered at 25 degrees north
latitude, 351 east longitude.  The region is approximately 160
kilometers (100 miles) across.  It shows a series of complex lava
flows which emerge from the northern flank of Sif Mons, a large
volcano just to the south.  Several of the flows occupy narrow
troughs formed by long fractures.  A sequence of events that can be
inferred from this image is the formation of the dark background
plains by eruptions of extremely fluid volcanic material, and the
formation of the small shield volcanoes on the plains surface that
can be seen in the upper left part of the image.  Next, the region
was domed upward probably by heat from the interior of Venus that
ultimately caused magmas to break out from the surface near the
summit regions forming the Sif volcanic structure and its
associated flank eruptions which can be seen in this image.  


                    Jet Propulsion Laboratory
               California Institute of Technology
          National Aeronautics and Space Administration
                   Pasadena, California 91109