The central estuary is also the location where mud
delivered by rivers accumulates, because it is generally
the deepest part of the estuary and a low-energy sink. In
addition, the central basin is the site for accumulation of
organic matter generated by shallow water biotic assemblages that might have been suspended in the water
column and transported into this low-energy area. As such,
the sediments accumulating in the central estuary range
from muds to organic-matter-enriched muds. Without bioturbation, the muds in the central estuary are laminated.
However, more generally, the muds in the central estuary
are thoroughly bioturbated. The central estuary is also
Stratigraphy of Estuaries, Figure 3 Main sedimentary sources and pathways of sediment movement within the Walpole-Nornalup
Inlet Estuary, a twin ria system with three river inputs, illustrating the principles of sediment particle sources and transport.
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STRATIGRAPHY OF ESTUARIES