The purpose of this project is to study
and correlate the unconformity and associated hiatus between
the Austin
Chalk and overlying rock units from Eagle Pass to San Antonio; to clarify
ambiguities in age
relation
between
the Olmos and San Miguel, Olmos and
Escondido formations and to evaluate the extent of the hiatus
between
Upper
Cretaceous and Lower Tertiary deposits in the study area. There are many
contradictions regarding age assignments and lateral relationships
between
the above mentioned units. In order to achieve the research goals, modern
concepts of sequence stratigraphy are applied using seismic stratigraphy,
well log, core, and outcrop-sedimentology, combined with palynostratigraphy
for high-resolution correlation of time and facies. Computer workstation-interpretation
is used for the 2D and 3D seismic data. This is expected to result in a
high-resolution chronostratigraphic framework, leading to achieving the
above research goals with high accuracy. Moreover, the present study is
an attempt to determine the effects of eustasy on the sediment distribution.
This comprises finding out if the relative changes of sea level are totally
due to eustatic changes of sea level or due to the combined effects of
tectonism, changes in the rate of sediment supply and eustatic sea level
changes. This methodology is thought to allow looking at the study area
in a more fresh way. Subsequently, new plays, not outlined by the old methods
will be discovered, and present plays will be re-discovered. This is because
of better understanding the chronostratigraphic relationships
between
them
within the interpreted regional chronostratigraphic framework in the study
area.
AAPG Search and Discovery Article #90925©1999 AAPG Foundation Grants-in-Aid