Sequence Stratigraphy - Trace Fossils as Indicators of Sedimentary Environments - page 152

Chapter 6
Sequence Stratigraphy
James A. MacEachern, * ,1 Shahin E. Dashtgard, * Dirk Knaust, †
Octavian Catuneanu, ‡ Kerrie L. Bann } and S. George Pemberton ‡
*ARISE, Department of Earth Sciences, Simon Fraser University, Burnaby, British Columbia,
Canada, † Statoil ASA, Stavanger, Norway, ‡ Department of Earth and Atmospheric Sciences,
University of Alberta, Edmonton, Alberta, Canada, } Ichnofacies Analysis Inc., Calgary, Alberta,
Canada
1 Corresponding author: e-mail: [e-mail]
1. INTRODUCTION
Sequence stratigraphy can be regarded as a methodology that employs stratal
stacking patterns and key bounding surfaces to erect a framework in which the
depositional facies of sedimentary environments can be mapped and interpreted
in the context of paleogeography (cf. Bhattacharya, 2011; Catuneanu et al., 2011 ).
Implicit in the methodology is that changes in stratal stacking patterns are a
response to changes in accommodation and sediment supply and that bounding
surfaces represent depositional breaks or changes in depositional architecture.
The concept of accommodation is central to sequence stratigraphy and indicates
the amount of space available for sediments to fill ( Jervey, 1988 ). Changes in
accommodation are controlled by shifts in the relative sea level (RSL), which
account for the interplay of eustasy and tectonism ( Posamentier and Allen, 1999 ).
The focus of sequence stratigraphy, historically, has been on allogenically
induced changes (e.g., eustasy, tectonics, climate), but more recent work has
included autogenically produced changes as well (e.g., delta lobe switching).
Additionally, unlike the analytical, objectively based stratigraphic methods
(e.g., lithostratigraphy and biostratigraphy), sequence stratigraphy is recog-
nized as “a genetic, process-based analytical approach to stratigraphic inter-
pretation that of necessity involves conceptual depositional models”
( Catuneanu et al., 2011 : 177). Today, our understanding of stratigraphic archi-
tecture largely rests upon sequence-stratigraphic frameworks.
Sequence-stratigraphic methodology is designed to be employed at a num-
ber of different scales, and as a result, the datasets utilized vary from outcrop,
core, geophysical well-logs, to seismic data. Ichnological data are largely
restricted to core- and outcrop-scale observations and can be applied to
sequence-stratigraphic problems at the same scale of observation as physical