Weathering Rinds by Jonathan Major

While on a field trip working in the Grand Staircase Escalante National Monument (GSENM) , a few members in our group came upon several cobbles of chert and quartzite cobbles with an unusual surface that I can best describe as a rind.   Each cobble of chert and quartzite had a black rind 1- 2 cm thick around it.  The cobbles are part of units such as the Canaan Peak.  The same cobbles are found Dakota Formation near Capitol Reef National Park.  The units were deposited in streams during the Cretaceous period of time.   The cobbles have since been reworked and deposited in the GSENM in alluvial terraces.

These rinds, sometimes referred to as patina apparently form from weathering on the outside of the cobbles that were deposited in braided streams deposits.  Analysis of similar rinds show iron, manganese and other elements like silica leaching out of the rock over time.  Some suggest  that the microflora aid in this process. 

Try as we might, we can't find any papers that are specific to the rinds on these Cretaceous conglomerates.  We would like to know more - the composition of the rinds, why they are so common in the Cretaceous (Sevier Orogenic) conglomerates.    Looks like a great future research project.

References

Baker, J. C., Edmonds, W. J., Ogg, C. M. (2001) Research Gate. Retrieved from http://www.researchgate.net/publication/232149104_Quartzite-Cobble_Weathering_in_Alluvial-Fan_Soils_of_the_Virginia_Blue_Ridge

Rajamani, V., Tripathi, J. K. (1999). Current Science. Retrieved from http://www.currentscience.ac.in/Downloads/article_id_076_09_1255_1258_0.pdf

Viveen, W., et al., Reconstructing the interacting effects of base level, climate, and tectonic uplift in the lower Miño River terrace record: A gradient modelling evaluation, Geomorphology (2013), http://dx.doi.org/10.1016/j.geomorph.2012.12.026

Wagner, G. A., (1998). Google Books. Retrieved from http://books.google.com/books?id=ADuZDCa08kwC&pg=PA37&lpg=PA37&dq=iron+rinds+on+chert+in+alluvial+terraces&source=bl&ots=txI_5azP_I&sig=PtZAyR89-EaP4nBfxXuCLq8ehVc&hl=en&sa=X&ei=6iVRU_6PJqbq2gXF0IGQAw&ved=0CEYQ6AEwBQ#v=onepage&q=iron%20rinds%20on%20chert%20in%20alluvial%20terraces&f=false

Diablo the Ceratopsian and more by Jason Scott Dillingham

Many animals and reptiles that exist today can seem relatable to the creatures in the past.  Imagine the beautiful Serengeti, the dry sun beating on your face.  Suddenly you feel the ground pounding and across the way you notice a muscular grey animal with large plates covering its body charging on all fours through the wilderness, armed with a horn atop its nose.  

Now, notice the sun getting warmer and more humid; the plant life: taller, greener, everywhere.  The ground shakes even more as a “snorting, stampeding, five-ton animal the size of a car, with a giant bony frill on its head, and you've got a fairly accurate picture of a ceratopsian dinosaur such as Triceratops” - a larger friend of the rhinoceros - charges by (Carroll, 1988). 

Ceratopsians (Greek for “horned faces”) date back to the late Jurassic period in Asia.  These species preceded Triceratops (up to the Late Cretaceous) and lacked the frills and horns that Triceratops had. Over time, predators such as the Tyrannosaurus Rex  came along and the Ceratopsians slowly evolved to defend themselves (Strauss, 2014). 

On our Geology field trip to the Grand Staircase, we first had to transport - before we even got to any digging sites - a skull of a Ceratopsidea (a frilled Ceratopsian) named Diablo to a museum where he could be displayed for people to view.  It was exciting to relate how large the animal could have been by the size of its skull, and encouraged me, personally, to get into the field and begin finding new things.

Throughout the trip, we broke up into two/three groups, one with Scott Richardson, the other with Alan Titus.  I was fortunate to participate in the group with Scott that went to a site where a discovery had already been made, but not completed.  “[Scott] discovered what is thought to be a previously unknown species of dinosaur similar to a triceratops, the latest in an extraordinary series of dinosaur finds in the area over the past 15 years (Hollenhorst, 2014).”  The discovery is still unclear, but the excitement endures on.

Sources

Hollenhorst, John.  http://www.ksl.com/?sid=29496320&nid=148&title=dinosaur-discoveries-in-utahs-amazing-place-get-national-attention&s_cid=queue-5 , 2014

Carroll, R.L. 1988. Vertebrate Paleontology and Evolution. W.H. Freeman and Company, New York.  Found on: http://www.ucmp.berkeley.edu/diapsids/ornithischia/ceratopsia.html

Strauss, Bob.  Ceratopsians - The Horned, Frilled Dinosaurs.  http://dinosaurs.about.com/od/typesofdinosaurs/a/ceratopsians.htm . 2014

Photo courtesy of James Montgomery