NASA Mars Rover Opportunity Grinds "Cool" Rock

coondoggie writes "While its sister rover Spirit has garnered most of the attention lately, NASA's other Mars traveler, Opportunity, is chewing up Martian dirt and unearthing the mineral and chemical makeup of the red planet. NASA scientists said this week the rover uncovered 'one of the coolest things Opportunity has found in a very long time:' a dark, basketball-sized rock known as 'Marquette Island.' According to NASA, the Marquette Island rock is a coarse-grained rock that indicates it cooled slowly from molten rock, allowing crystals time to grow. Such composition suggests it originated deep in the crust, not at the surface where it would cool quicker and have finer-grained texture, NASA stated."

Comments

Intrusive Igneous

[Drache Kubisuro]

So if this is a coarse grained rock with a basalt composition, then I guess that means it is a Martian gabbro (on earth they tend to be used ornately as black "granite" countertops). Which is highly interesting because that may indicate crustal deformation. Here on earth, such rocks form deep in the ground in what we call plutons. These are pockets of magma that differentially crystallize into grabbros and granites. Plate tectonics nudges them to the surface and weathering + erosion helps to uncover them. The Sierra Nevadas is a continuous grouping of them called a Batholith. Yes, all that granodiorite use to be underfoot!

Anyhow, this could be important in perhaps proving that, yes, at one point, Mars had active plate tectonics. Planet formation kind of requires it but good to know Mars may have had some crazy earthquakes in the past uplifting such rocks to the surface.