or bedrock, overlain by fluvial deposits, and then estuarine
deposits, followed by either a capping of deltaic deposits,
post-estuarine alluvial plain deposits, or transgressive barrier dune deposits.
At the scale of the estuarine basin, each of the estuarine
sub-environments listed above (viz., the major estuarinehead delta(s); subsidiary deltas; marginal estuary alluvial
fans; spits and their lagoons; marginal estuary environments, comprising platforms, tidal flats with some vegetated by mangrove and/or salt marsh, tidal flats with
biostromes; central estuary basin, comprising deepwater
environments; central estuary channels; tidal channels;
tidal channels fringed by biostromes; central estuary
shoals with some vegetated by mangrove and/or salt
marsh; margin of leeward side of the barrier; flood-tidal
delta; and washover fans) generates a specific and distinctive suite of sediments and, with accretion, will develop
either a longitudinal sequence or a mosaic of stratigraphic
units along and across the estuary basin, respectively, as
will be shown later in the case studies. The extent that individual facies are dispersed, or migrate laterally or downslope, will determine the extent that they are recorded in
adjoining facies and the extent that interfingering,
interlayering, or encroachment takes place and hence the
extent of the complexity of the whole-of-estuary
stratigraphy.
Stratigraphy of Estuaries, Figure 14 A series of transverse complex stratigraphic transects from south to north along the Fitzroy
River Estuary. The transects show fluvial-dominated stratigraphy to the south (inset D), followed by complex relationship further
north between early Holocene mangrove-developed mud deposits with large-scale cut and fill of later Holocene shoaling sand-tomud tidal deposits (inset C), a shoaling Holocene sand-to-mud sequence in central parts (inset B), and veneers on pre-Holocene
sediments and rock to the (distal) north (inset A) (Information from Semeniuk, 1980, Semeniuk, 1981 and Semeniuk and Brocx, 2011).
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STRATIGRAPHY OF ESTUARIES
deposits, followed by either a capping of deltaic deposits,
post-estuarine alluvial plain deposits, or transgressive barrier dune deposits.
At the scale of the estuarine basin, each of the estuarine
sub-environments listed above (viz., the major estuarinehead delta(s); subsidiary deltas; marginal estuary alluvial
fans; spits and their lagoons; marginal estuary environments, comprising platforms, tidal flats with some vegetated by mangrove and/or salt marsh, tidal flats with
biostromes; central estuary basin, comprising deepwater
environments; central estuary channels; tidal channels;
tidal channels fringed by biostromes; central estuary
shoals with some vegetated by mangrove and/or salt
marsh; margin of leeward side of the barrier; flood-tidal
delta; and washover fans) generates a specific and distinctive suite of sediments and, with accretion, will develop
either a longitudinal sequence or a mosaic of stratigraphic
units along and across the estuary basin, respectively, as
will be shown later in the case studies. The extent that individual facies are dispersed, or migrate laterally or downslope, will determine the extent that they are recorded in
adjoining facies and the extent that interfingering,
interlayering, or encroachment takes place and hence the
extent of the complexity of the whole-of-estuary
stratigraphy.
Stratigraphy of Estuaries, Figure 14 A series of transverse complex stratigraphic transects from south to north along the Fitzroy
River Estuary. The transects show fluvial-dominated stratigraphy to the south (inset D), followed by complex relationship further
north between early Holocene mangrove-developed mud deposits with large-scale cut and fill of later Holocene shoaling sand-tomud tidal deposits (inset C), a shoaling Holocene sand-to-mud sequence in central parts (inset B), and veneers on pre-Holocene
sediments and rock to the (distal) north (inset A) (Information from Semeniuk, 1980, Semeniuk, 1981 and Semeniuk and Brocx, 2011).
636
STRATIGRAPHY OF ESTUARIES