Speculation on Mars anamolous cratering

I have been reading Hancocks Mystery of Mars and am intrigued by the bizarre cratering of Mars. Portions of the crust on Mars show heavy cratering while opposite on the planet a general lack of impact craters are observed.

I tend to think that this disparity is the net result of several enormous impacts and thousnads of lesser ones that caused Mars to literally buckle from the resulting shockwave. The entire crust was shifted North and due to this planetkilling event threw the exsisting ( at the time just moments prior to impact ) atmosphere, liquid water oceans and any sign of life into space.







This is one big hole:




rst.gsfc.nasa.gov...

To emphasize the size of this structure: If all material excavated from it were to be spread evenly over the 48 continental United States, a layer of debris some 3.5 km (2 miles) thick would accrue. Below is an enlargement of the map covering this structure.

link to text: rst.gsfc.nasa.gov...

More on our enigamtic neighbor soon:

Alias Jones

More on Mars


Earth / Mars Size comparison:



This Chasm ripped the martian crust literally in two. The size of this canyon can not be overstated.

We start with the greatest trench in the ground ever discovered in the solar system. Look at this Mariner 9 mosaic, extracted from the near hemisphere view, here centered on the most conspicuous feature on Mars: the Valles Marineris which extends nearly 4,000 km (2,486 mi) and attains depths between 2 and 7 km (1.25-4.35 mi). When the outline of the 48 contiguous United States is overlain on mosaic, the eastern edge of Valles Marineris touches the Outer Banks of North Carolina and its western edge reaches to Central California.

The Valles Marineris

Why not to start from "closer" things like why some areas in moon are nearly craterless?
But now back to topic

Why does one side of Mars look more catastrophic than the other?

Very good site for info about Mars: (and solar system)
www.solarviews.com...

"The most curious aspect of the topographic map is the striking difference between the planet's low, smooth Northern Hemisphere and the heavily cratered Southern Hemisphere," which sits, on average, about three miles (five kilometers) higher than the north, Smith added. The MOLA data show that the Northern Hemisphere depression is distinctly not circular, and suggest that it was shaped by internal geologic processes during the earliest stages of martian evolution.

The massive Hellas impact basin in the Southern Hemisphere is another striking feature of the map. Nearly six miles (nine kilometers) deep and 1,300 miles (2,100 kilometers) across, the basin is surrounded by a ring of material that rises 1.25 miles (about two kilometers) above the surroundings and stretches out to 2,500 miles (4,000 kilometers) from the basin center.

This ring of material, likely thrown out of the basin during the impact of an asteroid, has a volume equivalent to a two-mile (3.5-kilometer) thick layer spread over the continental United States, and it contributes significantly to the high topography in the Southern Hemisphere.

Mars 3D

US Geological Survey info (and images) about Valles Marineris.
astrogeology.usgs.gov...

General info and links:
www.nineplanets.org...

Lot, I mean LOT of images:
photojournal.jpl.nasa.gov...
www.esa.int...






[edit on 14-9-2004 by E_T]

It is normal for cratering to exhibit large variations. The opposite is not normal. For example, Venus has a superbly uniform crater density. It's really hard to explain unless one thinks of a complete "resurfacing" once every 500 million years. It would be totally catastrophic.

Case in point, Mars was resurfaced like Earth, in parts, and not in one giant sweep. Resurfacing means mostly magma flow on the surface of the planet.