Archive for May 27th, 2010

Bryozoan Paradise at the K/T Boundary

May 27th, 2010

NEW ALBANY, MISSISSIPPI — One of the main advantages of being a geologist in a liberal arts program is the diversity of experiences our students and faculty have.  While some Wooster geologists are enjoying a “soft rock” adventure in the Cretaceous-Tertiary sediments in the Deep South, others are exploring “hard rock” quarries in the North.  Later this summer we may have simultaneous posts from Alaska, Iceland, Utah and Israel.

Today the southern expedition was very successful in its task to find bryozoans just below and just above the Cretaceous-Tertiary boundary.  Paul Taylor is a happy man.

Numerous bryozoans (the twig-like fossils) in the uppermost Cretaceous Prairie Bluff Formation east of New Albany, Union County, Mississippi.

The Cretaceous-Tertiary boundary east of New Albany, Union County, Mississippi. The uppermost Cretaceous is the brown clay, and the lowermost Tertiary is the orange sand at Megan's painted fingertip.

Which came first?

May 27th, 2010

NEW ALBANY, MISSISSIPPI — The Cretaceous oyster above was collected from the Coon Creek Beds of the Ripley Formation (Upper Cretaceous) near Blue Springs, Mississippi.  The holes are borings called Entobia which were produced by clionaid sponges which built a network of connected chambers inside the shell so that they could carry out their filter-feeding with some safety from grazing predators.  The branching white fossil is a cyclostome bryozoan, probably Voigtopora thurni.  Which was present first on the shell, the borings or the bryozoan?  Is there evidence that they were living at the same time?  The largest holes are about two millimeters in diameter.

PA Geological Survey Field Trip

May 27th, 2010

Sorry to have kept you waiting so long for the ending of the PA diabase field trip. Last Friday, we spent a wonderful day in the field with a group from the PA State Geological Survey.

Our first stop was the Pennsylvania Granite Quarry.

Dr. LeeAnn Srogi was an excellent host. Here she is describing the orientation of the Morgantown Sheet on the geologic map.

The PA geologists had the opportunity to examine the plagioclase layers and cross-cutting dark channels up close.

They even had a chance to see the big saw in action. (The PA Granite quarry guys are so good to us).

After a good laugh (oh, those geologists and their humor!) and a nice lunch in a local park, we headed to the Dyer quarry.

Here we're discussing the fault patterns in the Dyer quarry. The wonderful thing about being in the field with a dozen other geologists is that the discussions are invigorating. We are so fortunate that these professionals took the time to visit our field area and add their observations and ideas to our own.

After a week in the field, I have a notebook full of observations, a head full of ideas, and a trunk full of samples! Sounds like a good week to me.