Please check back for more information.

Bulletin Article

7963
 
Organic-carbon–rich shales of the lower Marcellus Formation were deposited at the toe and basinward of a prograding clinothem associated with a Mahantango Formation delta complex centered near Harrisburg, Pennsylvania. Distribution of these organic-carbon–rich shales was influenced by shifts in the delta complex driven by changes in rates of accommodation creation and by a topographically high carbonate bank that formed along the Findlay-Algonquin arch during deposition of the Onondaga Formation. Specifically, we interpret the Union Springs member (Shamokin Member of the Marcellus Formation) and the Onondaga Formation as comprising a single third-order depositional sequence. The Onondaga Formation was deposited in the lowstand to transgressive systems tract, and the Union Springs member was deposited in the transgressive, highstand, and falling-stage systems tract. The regional extent of parasequences, systems tracts, and the interpreted depositional sequence suggest that base-level fluctuations were primarily caused by allogenic forcing—eustasy, climate, or regional thermal uplift or subsidence—instead of basement fault reactivation as argued by previous workers. Paleowater depths in the region of Marcellus Formation black mudrock accumulation were at least 330 ft (100 m) as estimated by differences in strata thickness between the northwestern carbonate bank and basinal facies to the southeast. Geochemical analysis indicates anoxic to euxinic bottom-water conditions. These conditions were supported by a deep, stratified basin with a lack of circulation.
5776
 

The origin of thermogenic natural gas in the shallow stratigraphy of northeastern Pennsylvania is associated, in part, with interbedded coal identified in numerous outcrops of the Upper Devonian Catskill and Lock Haven Formations. Historically documented and newly identified locations of Upper Devonian coal stringers are shown to be widespread, both laterally across the region and vertically throughout the stratigraphic section of the Catskill and Lock Haven Formations. Coal samples exhibited considerable gas source potential with total organic carbon as high as 44.40% by weight, with a mean of 13.66% for 23 sample locations analyzed. Upper Devonian coal is thermogenically mature; calculated vitrinite reflectances range from 1.25% to 2.89%, with most samples falling within the dry-gas window. Source potential is further supported by gas shows observed while drilling through shallow, identifiable coal horizons, which are at times located within fresh groundwater aquifers. Thermogenic gas detected in area water wells during predrill baseline sampling is determined not only to be naturally occurring, but also common in the region.

DL Abstract

3104
 

Production from the Marcellus gas shale generated international interest when methane accumulated in the surface housing of a water well pump and exploded.

Explorer Article

2529
 

Pittsburgh brought a fresh and exciting feel to this year’s AAPG Annual Convention and Exhibition.

Explorer Division Column EMD

2470
 

In my 15 years as an AAPG member, I’ve actively been involved in planning and serving in various roles during AAPG’s Annual Convention and Exhibition (ACE), particularly when I lived in Houston.

Explorer Emphasis

2400
 

New data presents a new picture of health and safety issues in plays involving the Marcellus Shale.

2398
 

Terry Engelder is a professor at Penn State and expert on the Devonian black shales – all of which has brought a bit of celebrity expertise to the campus and the Marcellus Shale.

2385
 

An affair to remember: Bill Zagorski, the “Father of the Marcellus,” recalls the story of how the now-famed shale play got its start.

2462
 

Author Seamus McGraw sees both the upside and downside for the landowner in the development of the Marcellus shale.

Explorer Policy Watch

3186
 

The recent National Academies’ Institute of Medicine (IOM) report on its late-April 2012 workshop, “Health Impact Assessment of Shale Gas Extraction,” describes many potential health impacts of shale gas development and identifies the data gaps.

Workshop

Pittsburgh Pennsylvania United States 17 June, 2014 19 June, 2014 3780
 
Pittsburgh, Pennsylvania, United States
17-19 June 2014

Two of the top unconventional plays just keep getting stronger. Learn why they are successful, and how to optimize exploration and development.

Coming Soon

Check back often. "Find an Expert" feature is coming online soon!