First Wooster talk at the 2009 GSA meeting

Mark Wilson October 19th, 2009

PORTLAND, OREGON–By now I’ve given over 35 talks at annual Geological Society of America meetings, but I still get as nervous as I did as a graduate student. The cavernous room, the high quality of the previous presentations, the people coming in and sitting expectantly — it all comes to an exquisite tension as I hear the speaker before me say, “And in conclusion …”. We don’t read from a text or even use notes in these 15-minute sessions. It all comes from the slides and our desperate hope that we remember what to say at each. Somehow the adrenaline kicks in as you step up to the podium. The words flow and the slides become old friends with stories which must be told.

I’m in that magical post-talk phase of the meeting this evening with no more performance pressure. I can now happily share a few slides from our presentation, along with happy memories of the field and lab work:

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A Bit of Vertebrate Paleontology

Mark Wilson September 9th, 2009

MAKHTESH RAMON, ISRAEL–On my last day of fieldwork Yoav took me to some wonderfully complex exposures of Cretaceous and Tertiary rocks just north of Makhtesh Ramon. They tell a story of the origins of the Makhtesh anticlinal structure, especially the date it appeared and whether it was ever exposed as an island before its center was eroded away. Part of the debate comes down to the depth at which certain Santonian (Cretaceous) sediments were deposited. These sediments contain oysters and exquisite shark’s teeth. We collected a nice set (see below) which I will attempt to identify to see if we can use what we may know about these sharks to determine the depth of deposition.

Cretaceous shark teeth collected from just north of Makhtesh Ramon (N30.56235°, E34.64876°).

Cretaceous shark teeth collected from just north of Makhtesh Ramon (N30.56235°, E34.64876°).

Urban Dinosaurs

Mark Wilson May 27th, 2009

My last geological fieldwork (if we can call it that) in Israel on this trip was to examine the Upper Cretaceous limestones and dolomites exposed in Jerusalem. I far prefer my rocks be found in pristine wilderness areas with only bird songs in the background, but the right rocks, of course, can be anywhere. Sometimes, then, we have to work with traffic zooming by, sirens wailing, blasts of car exhaust, and schoolchildren offering to hammer the rocks for us.

The coolest location was in the moshav of Beit Zeit, just five minutes from downtown Jerusalem. (A moshav is a type of cooperative agricultural community, although in this case heavily urbanized.) A beautiful trackway of ornithomimosaur dinosaur footprints is exposed on a bedding plane of Lower Cenomanian limestone.

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The site is of great importance because thus far these are the only dinosaur tracks known in the entire Middle East. The local community purchased the land and erected a protective roof over the trackways. They had a mural painted showing what the area may have looked like in the Cretaceous, installed a custom-made life-size dinosaur model on the bedding plane, and made the area into an educational park. You can see for yourself what happened later. The surrounding fence was too low, so it became a drug hangout, vandals spray-painted the mural and then broke the dinosaur into bits. (The crater where the dinosaur stood is just visible in the photo.)  This natural wonder was simply too accessible to the public.  There are plans to protect the site more thoroughly, and then reconstruct the displays.

I was able to collect a small piece of the limestone bedding plane for analysis back in Wooster. My hypothesis is that the limestone is a marine hardground which cemented very soon after the dinosaurs waded across it, thereby preserving the prints. A thin-section of the rock may show if it had these early cements.

The rest of our urban geological work was on the streets of Jerusalem. Rocky outcrops are common because the city is built on several steep hills which have been quarried for thousands of years. We were able to correct the geological map in some places because of new exposures, and I gathered several ideas for future projects.

Mizzi hilu ("sweet rock"), a lithographic biomicrite member of the Judea Group (Turonian).

Mizzi hilu ("sweet rock"), a lithographic biomicrite member of the Judea Group (Turonian).