Siliclastic Influx
From http://www.ub.es/geoquimi/personal/sedi.html
Siliclastic
sedimentation within the region of shallow carbonate production is most dictated
by the character of the onshore sediments. Along with relative or absolute changes in sea level, storm deposits
and fuvial activity widely control the magnitude, extent, and character of
allochthonous siliclastic transport and deposition. The following list outlines considerations for siliclastic influence
on shallow water carbonates:
-The energy of the environment characterizes sediment
grain size. Typically coarser sediments
are found where hydraulic regimes are intense and finer sediments are allowed
to settle out of suspension in quieter waters. Storm deposits and regions where wave energy
is high exemplify the former, while lagoons (landward of rimmed platforms) and tidal flats may prescribe
the latter.
-A drop in sea level
or regional tectonic uplift may result
in a progradation of terrigenous sediment seaward. This newly introduced sediment may blanket
exposed carbonates and influence topography by controlling local weathering
(See Antecedent Topography: Karstification). A drop in sea level (or tectonic uplift) will
also change the local hydraulic regime along the profile of the platform as
deeper, quieter water locations become shallower and subsequently subjected
to higher energies and coarser siliclastic sediment accumulations.
-Suspended sediment may shallow the depth of the photic zone, which in turn can
deter the growth of benthic carbonate-producing organisms.