BEATY, SCOTT, Chevron, USA, Midland, Texas; W. LYNN WATNEY, Kansas Geological Survey, Lawrence, Kansas; and ALEX MARTINEZ, Exxon Exploration Company, Houston, Texas
Abstract: Analysis of Structural
Controls on the Development of the Upper Pennsylvanian Tonganoxie Incised
Paleovalley System of Northeast Kansas
The paleotectonic setting of the Tonganoxie
Sandstone (Upper Pennsylvanian, Virgilian) incised valley system in northeast
Kansas was analyzed using isopach maps
of the stratigraphic interval containing
a paleovalley-fill and lineaments
maps
based on presentday Precambrian
basement and potential fields data. Because structure
maps
of Upper Pennsylvanian
strata reveal little about the
structural
framework that influenced paleovalley
erosion and sedimentation, isopach
maps
were used to detect subtle changes
in local topography due to concurrent
structural
movement. Previous studies
along the eastern portion of the paleovalley system identified a large
trunk valley with smaller tributary valleys exhibiting rectilinear drainage.
Persistent linear thickness trends correspond
closely to trends of mapped lineaments, suggesting that basement reactivation
influenced the location of paleovalley development. Variations in thickness
of these stratigraphic intervals are related to differential subsidence
within distinct multi-km scale structural
blocks with boundaries oriented
predominately NW-SE and SW-NE. The rectilinear drainage pattern of the
Tonganoxie paleovalley was the result of movement along the
structural
blocks. The apparent link between present-day basement heterogeneity and
earlier
structural
developments suggests that reactivation along pre-existing
basement faults has been an episodic process in the northeast Kansas region.
Exploration for incised valleys should consider regional mapping of appropriate
stratigraphic intervals and related basement information to discern
structural
blocks and possible influence on valley incision.
AAPG Search and Discovery Article #90921©1999 AAPG Mid-Continent Section Meeting, Wichita, Kansas