Introduction
Eustatic sea-level stabilized near its present level
after the last glaciation between 5,000 to 7,000
years ago (Milliman and Emory 1968). Since that
time, sedimentation from the Mississippi River created
a series of overlapping deltaic lobes that presently
form the Mississippi deltaic plain in coastal
Louisiana (Scruton 1960; Roberts 1997). Each deltaic
lobe went through a cycle of active progradation
followed by river abandonment and subsequent
deterioration and submergence due to the
combined effects of shore-face erosion and coastal
subsidence (Penland et al. 1990). During the abandonment
phase, sediment and nutrients were delivered
to lobes adjacent to the river during spring
floods (Hatton et al. 1983). These floods provided
a source of mineral sediments, which contributed
directly to vertical accretion; nutrients associated
with these sediments promoted further vertical