Page 174 - Carbonate Platforms Facies, Sequences, and Evolution

160
corals
The
corals
of
in
third
the
source
of
uppermost
Pallini, 1977), which indicate
evidence
the northern Apennines,
Bugarone
favourable
the eventual drowning of the entire basin.
(Cecca
however,
concerning
et
drowning history of these seamounts comes from the
the
healthy buildups, which suggests that the ecological
water and
conditions were not quite right. Hermatypic corals
at.,
well-developed, relatively large corallites (Nicosia &
have been found at depths of 150 m at Bikini Atoll
1981; Mariotti et al., 1979; Nicosia & Pallini, 1977).
In most cases, these corals do not occur in typically
light conditions that are found in very shallow water.
(Wells, 1957), but they are stunted and rare. The
have
until
strate
based
means
shallow
the
on
seamounts
Apennines
that
that
D.M. Bice and K. G. Stewart
Although
very
the
depths
had
the
were
many
at
end
in
of
state
a
of
the
presence
the
identical
the
end
of
state
of
of
ooids
the
Jurassic,
drowning
Fig. 9. Thin-section
tops and the basins.
seamounts
and
not
incipient
were
from Monte Rotondo, 20X.
all
Jurassic,
Vida/ina martana as nucleus,
histories.
Crinoidi (lowermost Bugarone)
(a) Rosa a
(b)
still
from the Pliensbachian to at least the Tithonian.
aged sediments from the seamount
photomicrographs of Pliensbachian­
The importance of these corals is that they demon­
lOOX.
Same locality as (a); note ooid with
Monte Rotondo seamount, for example, appears to
The
which
of incipient drowning lasted
of the
at
the presence of the hermatypic corals
drowning
phreatic cements, as discussed above. However, the
freshwater
argues that many of the seamounts in the northern
have been at shallow depths during the Pliensbachian