Katherine Bergman1 and Sharon Stonecipher2
1 Department of Geology, University of
Regina
2 SHARON STONECIPHER, Marathon Oil
Abstract: Sequence
Stratigraphic
Analysis
of the lower Cretaceous
Spinney Hill Member (Basal Joli Fou Formation): Genetic
Implications of the Associated Glauconite
The lower Cretaceous Spinney Hill Member represents the
transition from estuarine complexes of the underlying Mannville
Group to the open marine shales of the Joli Fou Formation. In this
setting the Spinney Hill Member is contained in the Transgressive
Systems Tract (TST). Only the most general aspects of this
non-marine to marine transition were documented in the literature
despite relatively good well
log
control in south-central
Saskatchewan. The available core control is limited and most of the
core is 1 inch wireline. The non-marine to marine transition is
composed of several small scale Transgressive-Regressive (T-R)
cycles. Sandstone was deposited during the regressive phase and
mudstone during the transgressions. A
sequence
stratigraphic
framework based on the recognition and correlation of bounding
discontinuities in the Spinney Hill Member has been proposed and
from tiffs framework the details of sand body geometry and stacking
patterns were described. The depositional history and the history
of relative sea level during the onset of the Joli Fou
transgression follow from this framework. Based on the geometry of
the sand bodies and their overall stacking patterns the Spinney
Hill Member was interpreted as a series of backstepping incised
shoreface deposits formed during periods of stillstand in an
overall base level rise.
Both the sandstone and the mudstone in the Spinney Hill Member
contain associated glauconite. Glaucony beating horizons are
commonly associated with transgressions and typically occur at the
bases of T-R cyles. Sequence
stratigraphic studies have emphasized
the possible stratigraphic significance of glaucony, however the
distribution of glaucony in the different parts of a depositional
sequence
have not been
well
documented. The primary objective of
this project is to document the distribution and maturity of the
glaucony contained in the different pans of the depositional
sequences of the Spinney Hill Member to evaluate the stratigraphic
significance of the glauconite.
AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas