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Status of a reconnaissance field study of the Susitna basin, 2011

January 1, 2013

The Alaska Division of Geological & Geophysical Surveys (DGGS) and Alaska Division of Oil and Gas
(DOG), in collaboration with the U.S. Geological Survey (USGS) performed reconnaissance field studies for ten
days in late June 2011, in the Susitna basin, directly north of Cook Inlet, south-central Alaska (fig. 1). The purpose
of our investigation was to reconnoiter outcrops in the basin and along its periphery to gather new information
towards understanding the basin formation history and stratigraphy. This reconnaissance data represents the first
step toward better understanding the basin’s hydrocarbon potential, a key component of DGGS’s multi-year In-
State Gas Program. This program is focused on collecting baseline geologic information from potential frontier
gas basins to encourage new exploration to help, in part, reduce the high cost of energy in rural Alaska. Our work
represents the first season of this three-year project. Preliminary results from year two, a companion project within
the Nenana and Tanana basins in interior Alaska, are described by Wartes and others (2013). DGGS plans to return
to the Susitna basin for follow-up fieldwork during the third and final year of the program.


The motivation for developing a better understanding of the Susitna basin stems from the recognition that
the Susitna basin shares similar age coal-bearing strata with the adjacent, petroliferous Cook Inlet forearc basin
(Barnes, 1966; Reed and Nelson, 1980) and with exhumed strata in the Matanuska Valley forearc basin (Trop and
others, 2003) (figs. 1 and 2). Cook Inlet basin has eight producing oil fields, more than 25 producing gas fields,
and likely contains many additional undiscovered oil and gas accumulations (LePain and others, in press). Most
of the Cook Inlet gas is of microbial origin and apparently was sourced from abundant coalbeds of primarily
Miocene age in the Tyonek, Beluga, and Sterling Formations (Claypool and others, 1980; Magoon, 1994). If the
biogenic gas model for Cook Inlet is applicable to the Susitna basin, then the latter may be a viable source for
Alaska Railbelt and rural energy needs.


This brief overview report summarizes the reconnaissance field data collected in the Susitna basin during the
first summer of the program. As the data are developed, this report will be followed by interpretive technical reports
addressing the stratigraphy, reservoir quality, coal quality and gas potential, hydrocarbon seal integrity, subsurface
structure, and uplift history of the basin and sub-basin margins.

Publication Year 2013
Title Status of a reconnaissance field study of the Susitna basin, 2011
DOI 10.14509/25015
Authors Robert J. Gillis, Richard G. Stanley, David L. LePain, David J. Mauel, Trystan M. Herriott, Kenneth P. Helmold, C. Shaun Peterson, Marwan A. Wartes, Diane P. Shellenbaum
Publication Type Report
Publication Subtype State or Local Government Series
Index ID 70048255
Record Source USGS Publications Warehouse
USGS Organization Geology, Minerals, Energy, and Geophysics Science Center