GEOCHEMICAL DATA FOR JURASSIC DIABASE ASSOCIATED WITH EARLY MESOZOIC BASINS IN THE EASTERN UNITED STATES:

Report by Jeffrey N. Grossman, David Gottfried, and Albert J. Froelich, USGS Open-File Report, 91-322-J

Additional text by JGM

Through the kind efforts of the loyal staff at the Connecticut Geological and Natural History Survey, I recently obtained the geochemical files (on disk), the text descriptions, and the location maps for a large number of analyses published by Dave Gottfried, Al Froelich, and Jeff Grossman of the U. S. Geological Survey Reston office.  This report represents work partly in connection with the conferences that the USGS sponsored on Mesozoic basins in the 1980's (see references in the explanation file).  They were especially interested in the potential for platinum-group elements to be concentrated in cumulates within "sheets" or sills.  Also see Woodruff et al. (1995) for discussions about magma fractionation patterns.  I was absolutely delighted to find the treasure trove of volatile analyses in this databank, including H2O, CO2, S, F, and Cl!

I scanned the text files, which also contain the analytical files (with rough latitude and longitude as column headings), but my OCR program left many errors, not all of which I have found and corrected.  The tab-delineated data files are converted by my Excel spreadsheet.  The files are organized by Mesozoic basin.  As far as I can tell, they are all intrusive "diabase" analyses of dikes, sills, and "sheets" (sills that partially crosscut) associated with several Mesozoic basins of the eastern USA.  It is good that these are intrusives, because extrusive lavas in the basins tend to be much more altered.  There are many trace elements included, and details of the analytical methods are described in the introduction.  Because such reports are not copyright protected, I have felt free to post these data (Jeff Grossman did approve), but be sure to properly cite this open file report whenever you use it.  The files were a bear to keep formatted, so do not be surprised if you need to play with the columns etc. if you save them into your own workspace.  You should be able to put the tab-delineated data file into a spreadsheet or word processor to clean up, and then they are ready for IGPET or perhaps another petrology program.

Explanation of files:

The eight basin data files on this page contain the same data that are tabulated in parts B through I of U.S. Geological Survey Open-File Report 91-322.  The file names should be self-explanatory as to which basin the data belong.  The Introduction file contains the explanation of the analytical methods used in obtaining these data.  The user is referred to the text files for sample descriptions and locality information, including longitudes and latitudes.

Introduction

Southern Hartford Basin text file

Southern Hartford Basin data file

Eastern Newark Basin text file

Eastern Newark Basin data file

Western Newark Basin text file

Western Newark Basin data file

Gettysburg Basin data file

Culpeper Basin data file

Farmville Basin text file

Farmville Basin data file

Danville Basin text file

Danville Basin data file

Durham Basin text file

Durham Basin data file