46649-B2
Textural Controls on the Geochemical Variability of Argillaceous Hydrocarbon Source Rocks and Potential Application to Precambrian Units
Research Results
Work associated with the first year of my ACS-PRF grant (PRF No. 46649-B2) has been completed. The three most interesting findings related to my work thus far include: 1) many of the petroleum source rocks featured in the Argillaceous Rock Atlas contain considerable amounts of carbonate; 2) the use of metal ratios as redox indicators are often at odds with each other and with the textural evidence of depositional environment; and 3) subtle differences in geochemistry occur among samples from the same suite but deposited in different environments. Key collaborators on the project have been Drs. Wladyslaw Altermann (Ludwig-Maximilians-University), William Arnott (University of Ottawa), Lawrence Aspler (Grinnell College), Patrick Erickson (University of Pretoria), Linda Godfrey (Rutgers University), Neal O’Brien (SUNY Potsdam), Robert Rainbird (Geological Survey of Canada), and David Wright (Leicester University). Four students have been supported by the project thus far. A presentation is planned for the Geological Association of America meeting in Houston, Texas in October.
Impact on Student Learning and Training
During the first year of the project, four undergraduate students have worked with me. One student completed a senior thesis this spring whose goal was to add geochemical context to the Argillaceous Rock Atlas. Two students are currently finishing up summer research fellowships. One is compiling a set of over 1500 chemical analyses from the Early Proterozoic Pretoria Group in South Africa; another visited the archives at the Geological Survey of Canada and sampled several suites of organic-rich Proterozoic shales from the Canadian Shield. Several small suites of Archean shales have also been obtained, including shales associated with the ca. 3.3-3.5 Ga Barberton greenstone belt and from 2.6-2.7 Ga Hamersley Basin in West Australia. Several other interesting shale suites (e.g., Mesoproterozoic Proterozoic shales of the Mid-Continent rift and Neoproterozoic shales of the Windermere Supergroup) have been promised, and we await their arrival. In a piggy-back project, a summer research student sampled the entirety of the Marcellus Shale in 35 cores across New York State. This student will be hired to continue work on the Marcellus Shale this fall and perhaps the Utica Shale next summer in conjunction with Gastem, Inc., pending authorization of company funds.
Changes to the Research Plan
The original research plan of the project has been modified to allow greater student participation and to match summer and academic year schedules. For example, we have focused considerable effort on local Paleozoic shales. The Devonian Marcellus Shale is considered to have huge potential for hydrocarbons, particularly natural gas. Through a colleague, I was fortunate to sponsor a student at the New York State Museum this summer. His salary and expenses were paid by the Museum, but he worked in conjunction with me and his advisor at the Museum, Mr. Richard Nyahay, on the Marcellus Shale. We now have nearly 600 samples through the Marcellus Shale in Western New York. Many of these will be analyzed with the goal of building a chemostratigraphic database for the Marcellus Shale in New York State that can be eventually be extended throughout the basin. The initial data has been obtained, and the student is currently preparing additional samples and compiling the data.
Dissemination of Results
In order to disseminate our results, presentations are planned for several venues. The first talk will be presented at the Geological Society of America meeting in Houston in October in Session T27 From mud to mudrock: Use of modern depositional settings as analogs for the interpretation of ancient mudrocks by Mr. Evan Blumberg. Evan completed his senior honors thesis with me and now attends Northern Colorado State, where he is enrolled in a Master’s program in geology. Dissemination plans also include several papers and various posters and talks at the NE regional meeting of the Geological Society of America and perhaps at the June 2009 meeting of the AAPG to be held in Denver, Colorado.
Future Plans
Our future plans include the continuation of the project with emphasis on: 1) preparation and further analysis of select suites of Precambrian shale samples; 2) preparation and analysis of samples from the Marcellus Shale in New York State; and 3) possible extension of the work to include the Utica Shale. This work should lead to a variety of presentations and publications. At the present time, several manuscripts are planned, including a review paper for the Journal of African Earth Sciences on the shale geochemistry of the Pretoria Group, the shale geochemistry of the samples from the Argillaceous Rock Atlas, and a paper on the chemostratigraphy of the Marcellus Shale. Much of the final work on the manuscripts will be completed next year (2009-2010), while I am on sabbatical.
