Chris Butterworth’s blog:

On our way to GSA we stopped at Joplin History and Mineral Museum in Missouri, where there are displays of mining equipment and samples of the minerals mined there.  These are mainly galena and calcite.  Upstairs are models of the local mines, showing shafts and seams.  There are also displays of items from a bygone age, as are found in most local museums.  There were vendors of gems, minerals and fossils, and I bought a couple of 40 million year old (according to the vendor) shark teeth for my son.  I avoided the Moroccan trilobites as they have a reputation for being fake.

In Kansas we stopped at Fort Hays State University’s Sternberg Museum of Natural History.  This is a large building under a dome, with a simulated journey through time in the middle, with large mockups of dinosaurs, one of which growls so loudly that it can be heard all over the museum.  For a local museum this one has an impressive set of collections, which are Paleontology, Paleobotany, Geology, Botany, and Zoology.  Most of these were relevant to us.  I photographed all the snakes in the exhibit at the lower level under the central dome.  These were of interest to me, having studied zoology in the spring.  Then I walked up the slope representing different geological periods, with models of various reptiles.  For the 80 million year point was also marked by a boundary between Kansas and Colorado, mainly because of the location of local sites where many fossils were found.  The actual fossils were displayed in glass cases, including their famous “fish within a fish.”  I took a selfie in front of a mammoth skeleton, and then tried to take in the dozens of minerals on display.  I would have liked to stay for longer but we were on a schedule.

I spent my first day at the annual meeting of the GSA in Denver listening to talks about Mars.  The morning session was a collection of talks about sedimentary geology in Gale Crater, based on satellite photos and data collected by Curiosity Rover.  The afternoon session was about igneous geology from previous Mars missions and from meteorites from Mali.  I have chosen to write about a morning session talk by Kathryn M. Stack called “Facies Analysis and Stratigraphic Context of the Pahrump Hills Outcrop, Type Locality of the Basal Murray Formation, Gale Crater, Mars.”

Curiosity Rover has spent the last four years climbing Mount Sharp in Gale Crater.  This sounds dramatic but the “mountain” is actually not steep and the rover can easily drive up its gradient.

The rover landed at a place called Aeolis Palus at the foot of Mount Sharp, which lies within Gale Crater.  The area is named for the type of deposits found there: wind-blown sediments, with coarse cross-bedding.  Satellite photos show that this is in the lowest unit of Mount Sharp, the Murray Formation.  Curiosity spent two years there and then crossed a facies boundary into the Palump Hills outcrop.  Here it photographed features such as conglomerate rocks, resistant ridges, platy-bedded lenses, and resistant outcrops.  In the distance could be seen the mesas of the Bradbury Group and the Stimson Sandstones.

The field strategy used was to walk this outcrop using Curiosity’s ChemCam, which can do laser spectroscopy, and its MastCam.  Several stops were selected because they looked interesting, and, for the sake of objectivity, other points were chosen between these spots precisely because they were not interesting.  The rover’s core sampling drill and its “hand-lens” tool were used to examine the rocks at some of the points.  The sandstones and gravels found here were of fluvial origin but the mudstones had grains so fine that they could not be resolved under the lens.  They must have been deposited under deep water, and some of their laminations were fine and regular, others less well-expressed.

Kathryn described some bedding features called “scour and scrape” structures, along with the “climbing ripples” found at a feature called Newspaper Rock.  Rover was able to examine sandstone from a higher elevation without going there, because a large boulder had rolled down the hill.  At this point Kathryn’s team was able to reconstruct the depositional environment as being plunging plumes which created mudstone in lacustrine varves, without aeolian ripples.  The scour and drape bedding was, apparently, indicative of hyperpycnal flows.  The overall environment was a deep body of varying depth, with plunging river plumes flowing turbidly down the slopes.

One of Kathryn’s team members is Dr Linda Kah, with whom I hope to do some research for my Master’s in Applied Science.  This talk gave a very interesting background into the work being done by Curiosity Rover in Gale Crater.

On Monday I spent the morning as an alternate student volunteer, and in the afternoon attended the sessions on Aeolian transport mechanisms.  Most of these talks were about Mars, and there was much overlap with the previous day’s material.