RE: Clastic or Carbonate

["Thomas R. Holtz, Jr." <tholtz@umd.edu>]

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of Amanda Northrop
>
> Hi list,
> 
>  I have to choose between two classes to take to fulfill my 
> B.S. in Geology requirements.  I'm wondering if you know 
> which one would be more useful in the study of paleontology.  
> Here are there descriptions:
>  GEOL 241 - Clastic Depositional Systems.  Selected readings 
> and field studies emphasizing the interpretation of clastic 
> sedimentary deposits including transportation, processes of 
> sedimentation, and geomorphology of ancient and recent 
> sedimentary environments.
> or
> 
>  GEOL 245 - Carbonate Depositional Environents. 
> Paleoenvironmental analysis of carbonate rocks including 
> selected readings, field investigations, and petrographic studies.
> 
> Which would you take?  I'm not really clear on the difference 
> between "clastic" and "carbonate."
> 
> Off-list replies are fine if this is off-subject.
> 
> Thanks!
> 
> Amanda Northrop
> University of Vermont

Clastic: sand, mud, etc. Carbonate: calcite, aragonite, dolomite.

Or: clastic = trip to the countryside; carbonate = trip to the Bahamas.

The vast majority of dinosaur fossils are in clastic systems (streams,
lakes, deltas, etc.); those in carbonates were ones who washed offshore onto
carbonate banks, died in tropical lagoons, etc. But carbonate seds are
chalkful... Er, chockful (okay, old joke...) of fossils of marine organisms.
Indeed, many carbonate rocks ARE fossils of marine organisms!

Take BOTH is you can manage it!!! Trust me, in this day and age finding
separate undergrad classes for clastics and carbonates is getting very
difficult, and most universities long ago combined the two into a "Sediment
& Stratigraphy class".

If push comes to shove, though, take clastics if you are interested in
dinosaurs, other terrestrial vertebrates, and land plants; and carbonates if
you are interested in anything else.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Earth, Life & Time Program, College Park Scholars
http://www.geol.umd.edu/~jmerck/eltsite/
Fax: 301-405-0796

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA