The application of high‐resolution sequence stratigraphy to fluvial systems: a case study from the Upper Carboniferous Breathitt Group, eastern Kentucky, USA

Abstract

The Pennsylvanian Pikeville, Hyden and Four Corners formations of the Breathitt Group in eastern Kentucky, USA, contain six major facies associations along with a number of subassociations. These facies associations are offshore siltstone, rhythmically bedded mouthbar heteroliths, predominantly fine-grained floodplain deposits, minor channel fills, major distributary channels and major, stacked fluvial bodies. The stacked fluvial bodies are incised into a variety of open marine and delta plain deposits, have widths of several kilometres and exhibit a range of sandy fill types. These fluvial complexes are interpreted as incised valley fills.Parasequences and parasequence sets are not identifiable. Nonetheless, it is possible to identify systems tracts on the basis of sequential position, facies associations and systematic changes in architectural style and sediment body geometries. The studied portion of the Breathitt Group comprises stacked 4th-order sequences, which occur in lowstand, transgressive and highstand sequence sets related to the development of a lower frequency base level cycle.In the lowstand sequence set, incision associated with successive 4th-order sequence boundaries has commonly removed all the HST and TST of the underlying sequences, such that succeeding 4th-order incised valley fills are amalgamated. Within the transgressive sequence set, incision is at a minimum and incised valley fills tend to stack discretely with the maximum amount of fine-grained TST and HST between them. The highstand sequence set is transitional between the lowstand and transgressive sequence sets in terms of the amount of transgressive and highstand deposits preserved. Incised valley fills tend to stack discretely.

Sedimentology and sequence stratigraphy of the Lopingian (Late Permian) coal measures in southwestern China

“…Best and Ashworth, 1997), the sequence boundaries are identified by a number of features such as being larger-scaled and having overlying amalgamated channel-fill facies that indicate lowaccommodation conditions (Schumm, 1993;Catuneanu et al, 2009). In the study area, it is also possible to locally trace interfluve palaeosol development by following the base of adjacent incised valley infills (Aitken and Flint, 1995). In some locations, especially in the seaward parts of the study area, small falls in sea level may lead to difficulties in identifying hiatuses or non-depositional surfaces that could serve as sequence boundaries.…”

Alluvial facies and paleosols in the Cretaceous Nanushuk formation, Kanayut River, North Slope, Alaska, Preliminary results from the 2001 field season

“…Highstand time was interpreted by McCabe (1993, 1994) to be characterized by continued rapid generation of accommodation as the fluvial equilibrium profile moved rapidly basinward. However, Wright and Marriott (1993) and Aitken and Flint (1995) considered the HST to be characterized by a progressively diminishing accommodation rate, reflected in progressive channel amalgamation and better developed paleosols, and culminating in complete sediment bypass as relative sea level began to fall. In Wright and Marriott's (1993) model, the degree of pedogenic maturity and soil drainage of coastal plain paleosols varies at different times in the relative sea level cycle.…”

Anatomy of a Fluvial Lowstand Wedge: The Avilé Member of the Agrio Formation (Hauterivian) in Central Neuquén Basin (Northwest Neuquén Province), Argentina

“…This is interpreted as a function of reducing fluvial gradient/increasing non-marine accommodation related to a general, long-term base-level rise. Similar trends have been interpreted from depositional systems of all ages around the world (Shanley & McCabe, 1994;Aitken & Flint, 1995;Olsen et al, 1995;Marriott, 1999). Considering that these non-marine deposits were accumulated in the central part of the basin following a major relative sea-level fall (lowstand), the amalgamation of thick, coarse-grained packages associated with bedload braided fluvial systems is interpreted as a response to low accommodation conditions generated by the relative sea-level fall.…”