STRATIGRAPHIC ALIASING AND THE TRANSIENT NATURE OF DEPOSITIONAL CYCLICTY: DOES THE DEEP-WATER SEQUENCE MODEL NEED REVISION?

Conventional sequence stratigraphic models applied to submarine fans ascribe cyclic arrangements of facies to relative changes in sea level, and deep-water sedimentation preferentially to sea level low stands. Although elements of this model appear to apply to late Pleistocene-Holocene systems (the last 35 kyr), published studies of older examples suggest a more complex relationship between sedimentation and drivers. Here, we draw attention to examples from the Mississippi fan that deviate from conventional models. An intriguing observation is that at low rates of accumulation, the frequency of sedimentary cyclicity is lower than that of associated sea-level change, whereas at high rates of accumulation, the opposite is true. We suggest that such mismatches in frequency – which we refer to as stratigraphic aliasing – provide new insight into the origins of deep-marine sedimentation patterns. It is rarely the case that depositional cyclicity corresponds in a simple way with sea-level cyclicity, calling into question a longstanding assumption of deep-water sequence stratigraphy.