The criss-cross lines don't quite look like a Widmanstätten pattern. They have a less crystalline appearance and seem rounded and have something that looks like droplets near the ends.

Let me suggest two more possibilities:
* A Widmanstätten pattern was modified by melting during atmospheric entry.
* Widmanstätten patterns have nothing to do with it, and we're looking at flows of viscous melt during different phases of entry.

Steve M

I initially though that this could be a Mesosiderite which would explain the deep cavities, but on reflection these cavities and the pronounced etching of the surface are most easily explained by initial burial of the meteorite and exposure to the acidic groundwater proposed by JPL. And there is an example of this process available.

http://en.wikipedia.org/wiki/Willamette_Meteorite

In fact this meteorite could well be the definitive smoking gun supporting the JPL theory for Meridiani and finally putting the surge alternative to bed. (As I duck for cover I wish we had an emoticon with a crash helmet).

I would whole-heartedly agree with that.

I'm not a meteorite expert, but regarding the possible Widmanstatten patterns, this would be the first time I've seen them exposed on a naturally weathered, meteorite surface. The geometry of these features seems right, but I would expect the patterns to be more repetitive, if you know what I mean.

I think I see what you're saying, serpens. Since we normally etch iron-nickel meteorites with acid to expose their Widmanstatten structure, the fact that this naturally weathered, Martian meteorite may be displaying such internal crystallinity on its surface suggests that it may have been exposed to an acidic environment in its past. Interesting.

Block Island was definitely worthy of the effort to go to back for a second look. I never dared to dream that I might, one day, be able to explore another world like this. What a ride this has been!

I understand the caution and doubt from a scientific perspective. But you have to start somewhere. You take a bit of speculation and develop it to come up with a hypothesis that can be tested. That's all I've done.

The blueberries need acid to form, but that wouldn't last long in this soil. That suggests a mechanism other than simply groundwater must have played a part. If SO2 from volcanism played a significant part in atmospheric warming instead of the normally accepted CO2, then interaction of dust and atmosphere to make the necessary acid on top of the glacial ice field is a possibility. In fact, its a high probability that this scenario is the correct one because of the sulfates found...yet no limestone deposits have been discovered anywhere on Mars.

Was there groundwater? Of course. If there was glacial melt and sublimation, then there must have been ground water too. But groundwater alone cannot explain all the variables found in the soil at Meridiani. Ice and atmospheric interaction provides a convenient method over an extended period of time to change the top layers of the soil from basic to acid and back to basic again.

The fact is that we don't know how the blueberries were formed. Figure out the real conditions present eons ago, and we might have a chance to figure out exactly how the blueberries developed.

But a simpler explanation is a groundwater playa in a basaltic environment with a period of volcanism that created an acidic aquifer that overcame the natural buffering until the acidification influence diminished and the natural buffering took over again.

But the distribution of of the berries does not suggest this. In fact, multiple cycles of basic, acid, basic, acid, basic, acid, and basic are suggested because the berries are through all the layers. One prolonged period would have created berries similar to Earth examples...meaning a lot larger and a different distribution.

Why do people continue to fight the obvious? The martian climate has changed drastically in certain ways. A water table appearing and disappearing as you suggest is just another type of climate change, but no less dramatic. So if the climate changed in one way, why not in an alternative way that can explain things? All the ingredients were present. It is just a question of form.

Mars was warmer in the distant past. There was liquid water present at one time or another. Today liquid water cannot exist on the surface of Mars for long because of the thin atmosphere. Is it such a leap of logic that the once liquid water must have gone somewhere, like became frozen near the surface, before it eventually migrated through sublimation to the current poles? And we know for a fact that those poles were not always Mar's poles.

If you want to have an argument about the history of Meridiani, can you start a new thread please.

edit : I see someone decided to ignore this request. Post deleted. Twice.

How big is Block Island? I make it very roughly this size...

What's the prevailing wind direction indicated by the smoothed edge of this rock? It's interesting that the dunes to the east seem to have a longer wavelength. Wake effect?

[quote name='Stu' post='144234' date='Aug 3 2009, 11:30 AM']How big is Block Island? I make it very roughly this size...


It looks like its being held over someones head. Block Island is a foot high and at least two feet across, probably weighs nearly half a ton. It would be more realistic to show someone crushed underneath it.

I thought "you" were not able to convert foot to metrics, I see now you're not even able to make a difference between hand and foot

Anyone else out there guess I wasn't going for "realism"? haha! The hand is simply there for scale!

Well, I guess you could make it a 3D animation where BI is rotating on your index finger like a Harlem Globetrotter's basketball! But I guess we need more data for realism. We need a peek at the underside of the rock 1st before we can create an accurate rendition.

Playing with an image registration tool and the last MI images.

Looks like a high percentage of metallic minerals reflecting so much light. Seems like these are fairly common on Mars. Are Iron-Nickel meteors more common on Mars because of proximity to the Asteroid Belt, or are meteors preserved due to lack of weathering and other geologic forces that allow them to concentrate on the surface much more than Earth?