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

3103
 

Assets within the Appalachian Basin range from conventional clastic and carbonate reservoirs to source rocks of Devonian black shale and Pennsylvanian coal, all of which are fractured.

3104
 

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

3102
 

Challenges for global gas shale production include infrastructural and geological with the Marcellus providing an analogue for both. (Infrastructural) The production from the Marcellus gas shale presents unique challenges that include issues associated with leasing, geology, landowners, virtually no deep disposal wells, state governments without a severance tax, several river basin commissions, an infrastructure designed for shallow gas production, an emotional group of environmentalists, and one state that has yet to permit horizontal well stimulation.

Environmental Geosciences Article

5780
 
We use sediment ages and mercury (Hg) concentrations to estimate past and future concentrations in the South River, Virginia, where Hg was released between 1930 and 1950 from a manufacturing process related to nylon production. In a previous study, along a 40 km (25 mi) reach, samples were collected from 26 of 54 fine-grained deposits that formed in the lee of large wood obstructions in the channel and analyzed for grain size, Hg concentration, and organic content. We also obtained radiometric dates from six deposits. To create a history that reflects the full concentration distribution (which contains concentrations as high as 900 mg/kg [900 ppm]), here, we treat the deposits as a single reservoir exchanging contaminated sediments with the overlying water column, and assume that the total sediment mass in storage and the distribution of sediment ages are time invariant. We use reservoir theory to reconstruct the annual history of Hg concentration on suspended sediment using data from our previous study and new results presented here. Many different reconstructed histories fit our data. To constrain results, we use information from a well-preserved core (and our estimate of the total mass of Hg stored in 2007) to specify the years associated with the peak concentration of 900 mg/kg. Our results indicate that around 850 kg (1874 lb) of Hg was stored in the deposits between 1955 and 1961, compared to only 80 kg (176 lb) today. Simulations of future Hg remediation suggest that 100-yr timescales will be needed for the South River to remove Hg-contaminated sediments from the channel perimeter through natural processes.

Explorer Article

8049
 

Online registration is open for this year’s AAPG Annual Convention and Exhibition, which will be held April 6-9 at the George R. Brown Convention Center in Houston – and reduced registration fees are still available for those who act fast.

3785
 

Energy is required to secure, treat and distribute water; conversely, energy production depends on an abundant and reliable source of water.

Explorer Emphasis

8058
 

Induced seismicity has been the bane of hydraulic fracturing’s public image, but research is underway to determine the precise culprit for seemingly unnatural earthquakes.

8050
 

Seismic Outlook: After several years of plenty, 2014 is expected to be a comparatively lean year for the seismic industry, a few localized hot-spots around the world notwithstanding.

Field Seminar

Columbia South Carolina United States 04 September, 2014 11 September, 2014 2575
 
Columbia, South Carolina, United States
4-11 September 2014

This field seminar offers an excellent opportunity for the students to walk on a variety of modern terrigenous clastic depositional systems while observing sedimentary processes, modern sedimentary structures, and numerous trenches illuminating the three-dimensional architecture of each area.

Watkins Glen New York United States 23 June, 2014 27 June, 2014 147
 
Watkins Glen, New York, United States
23-27 June 2014

The attendee will gain a working knowledge concerning how faults and fractures develop and their terminology, methodologies utilized in collecting and analyzing fracture data, characteristics of faults and fractures that affect the sedimentary units (including black shales) in the northern Appalachian Basin of New York state, and tectonics that led to the formation of the structures in the northern Appalachian Basin and the adjacent Appalachian Orogen.

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.

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Peter MacKenzie Peter MacKenzie Advisory Counselor (2013-2016) Ohio Oil & Gas Association (614) 715-2952
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