The "Mars Grid"
Brief Discussion and Analysis

Ron Nicks (Terracon)
Enterprise Mission Consulting Geologist

With Additional Notes By Mike Bara

The following is a brief discussion of a cursory inspection that I have made of a recent, seemingly suddenly interesting grid pattern present on a Mars image.

From MOC Image M03-04818

This is an excellent example of what our JPL scientists have explained regarding the illusion of inverted topography.  Staring at the image can at first convince you that the “grid” is a negative feature.  That is to say the grid itself is much like that which you would get if you smashed a piece of window screen into soft modeling clay, and then removed the screen.  Continued eye strain into the matter can convince you that no, the grid is a positive feature, much like the “grid” that you see on your morning Eggos.  So, which is it?

It appears to me that the light is coming from a high angle nearly directly behind the viewer to slightly over the viewer’s right shoulder.  If that is true, then close inspection of the “horizontal” grid lines should reveal that they are darkest along their upper edge if they are of positive topographic expression.  In other words, the horizontal grid shadow will be cast toward the top of the image.  That is exactly the case.  If the “lines” were depressions, then their upper edges would be lighter because of the aforementioned light angle.  Regarding the “vertical” grid lines, it is striking that it is very difficult to make a similar analysis.  That, of course, is due to the high sun angle almost directly behind the viewer, with a sun azimuth relative to the trend of the “verticals” being almost parallel.  However, there are a few areas toward the left edge of the image where it can be seen that the lighter portion of a few “vertical” lineations is along the right side of the feature; exactly what you would expect if the feature was raised, or extended above the immediately surrounding terrain.  From this tenuous evidence I guess it is fairly obvious that at present (I’m open to more detailed analysis), I believe the “grid” to be of positive relief.  In other words, the Eggo. 

Rectilinear recessed fracturing in Utah. Blocks are raised features over the "grid,"
and note general irregularity of recessed grid pattern

That said, it doesn’t get any easier to explain a few additional conditions apparently evident on the image.  But first, what natural process could create a grid-like pattern across the landscape?  There are examples of high-angle rectilinear patterns here on earth.  Generally they are related to high-angle joint sets, typically seen in granitic or sedimentary type terrain.  But the case in point is, for the purposes of this discussion, considered to be a grid of positive relief, not just a grid pattern.  How could such a condition be natural in a pattern of joints?  As usual, being a geologist, I have to ask the reader to indulge me in presenting a slightly involved process that upon more detailed analysis might be easily dismissed in the Martian case.  I don’t know.  Time and more analysis will tell. 

In a nutshell, the process is this.  Due to the nature of the atomic structure of some minerals, and mineral assemblages, regular, very regular, cleavage, and in the case of clays, platiness is common.  Having said that, and given a couple of “ifs” the issue of a grid of positive relief could be explained.  First if.  If there is a material present with regular and predictable cleavage, then one could expect regular “joint” sets, or rectilinear patterns, even though, strictly speaking, joints aren’t necessarily related to cleavage.  Second if.  If there was a mineral-rich water circulating among the joints, then it is possible that deposition in those joints could be harder than the country rock.  That would result in the eroding of the country rock at a slightly greater rate than the material deposited in the joints—thus, the joints become a feature of positive relief, relative to the country rock.  I have seen many examples of this in the arid, desert southwest of the US.  However, those examples are more directly related to faulting and fault zones that become more cemented (harder) than the adjacent surrounding rock.  So, given my “ifs”, there is a strong possibility that such a raised grid pattern could be natural. 

Assume for the moment that the grid is the product of a natural geologic process.  Given that, I do have a few questions.  How is it possible that the “grid” has not been buried by the storms on Mars?  You know, the ones that conveniently deposit "dune trains" in the canyons?  The first answer might be—This is an area of denudation.  OK, denudation for how long?  Forever?  Is there never a wind that might, just might deposit sand in at least a preferred corner, based on wind direction, of each, or at least some, of the cells?  I suspect that the answer is yes.  There should be deposits in the corners of the cells based on the direction of the last wind.  But, I see no such regular deposition.  Why?  I don’t know for sure.  There are some reasonable, and plausible answers I suspect, but I’m not sure that they can be gleaned from the topic image alone.  There is also a possibility, assured to be unpopular with the naturalists, that the grid is the remains of a roof structure and any incoming dust or depositional debris simply falls through, and whatever is below hasn’t filled up yet.  Obviously, all this is speculation, nevertheless, it is possible.  There is even a slight hint that it might also be plausible.  In the upper left center of the image is a nearly circular, absolutely black spot.  Could that be a glimpse into the void below?  Again, I don’t know.  The spot may be an artifact of the imagery. 

Note: The hole Ron is referring to appears to be a legitimate depression in the topography, not any kind of image artifact. You can see the surrounding terrain actually "overflows" into the crater. There is no ejecta blanket, indicating it is a collapse or puncture feature, not an impact crater. And it is very circular. -- MB

There has been some talk of the grid pattern possibly being attributable to trellis-type drainage.  Although that might be an attractive option to some, the grid displayed in the Mars image simply does not meet the requirements necessary to be derived from trellis-type drainage. 

Trellis drainage is typically found in terrain comprised of semi-parallel mountains with intervening valleys.  The trellis pattern derives from youthful streams cascading down the mountainside and intersecting the main valley stream at nearly a right angle.  With tributaries entering from both sides of the main valley stream, it gives the impression of a rectilinear pattern.  Close inspection of such terrain will reveal that, for the most part, the pattern is composed of a series of what appears to be rectangles outlined by streams.   In reality, each “cell” is an area flanked on only 3 sides by a stream, that is to say the two tributary sides, and the main valley side.  The open side being the area between the headwaters of the tributaries.   

The grid image from Mars clearly shows completely enclosed “cells”, rectangles of very regular interval, and, at least on an individual cell basis, very straight edges.  Topography at the site of the Mars image also does not support a trellis drainage scenario for development of the obvious grid pattern.  There is no evidence of parallel or sub-parallel mountain ranges or hills in the grid area.  Just the opposite seems to be evident.  The area on Mars appears to be relatively flat, and horizontal.  No, I don’t think trellis drainage provides the best explanation.  Actually, trellis drainage patterns just give the impression of rectilinearity, and do not really consist of a series of closed rectangles. 

Further support for the artificialists can be found in close inspection of the “horizontal” grid lines.  In fact, they are not straight lines.  They are broad arcs with a radial center far, far away toward the top of the image.  The “vertical” grid lines however, appear to be absolutely straight radii.  Again, however, I’m constrained to the image itself, and realize, that such an observation is moot unless the image has been orthographically corrected.  If I assume that the image is orthographically correct, then could it be that we are seeing a portion of the “roof” of a huge arcology built in the manner of Buckminster Fuller? 

The plot thickens, the blood (of some) boils, and the beat goes on. 

Additional Notes - The image as discussed by Ron comes from the non-map projected version. In fact, the orthographically rectified version of the image shows the radial nature of the grid to be even more pronounced.

To my knowledge, this image was first mentioned by Keith Laney over at "Target Mars." Mac Tonnies over at "The Cydonia Imperative" has also compared this to the MOC image M02-00351 in Alba Patera, which we first covered last year in our online paper "Analysis of apparent architectural features on Mars." The major differences, to my eye at least, is that the "grid" on M02-00351 is recessed, as opposed to being raised, and more of the area is covered in dust. But is is clear that the grid continues under the dust and is very regular, even if the blocks are not. -- MB

Two examples of features from M02-00351