Although the original field
studies were conducted more
than 40 years ago, this
paper attempts to resolve
some of the controversial
issues regarding the
Cretaceous and Paleogene
rocks, particularly the
Pandan Formation and Cansi
Volcanics, whose geologic
ages must now be reviewed in
the light of subsequent
findings which have remained
unpublished. I take this
also as an opportunity to
set the records straight
with regards to the
Paleogene units, the Baye
Formation and Lutak
Limestone, whose paternity
has been unfairly attributed
unwittingly to other
innocent parties for which I
may be held party to blame.
The
real key to possible
solution of the Pandan/Cansi
problem was our Baye
Formation in Asturias,
originally mapped as part of
the Pandan but hastily
excluded from it toward the
culmination of our final
mapping of central Cebu in
1956 because of the presence
of Eocene (Flosculinabearing)
limestone together with
Cretaceous (Orbitolina-bearing)
limestone clasts in
conglomerate beds which
placed its approximate age
as Late Eocene to Early
Oligocene. It was named the
Baye Formation accordingly.
In my
recent review of the
geologic literature covering
Cebu that has accumulated
during the last 4 decades, I
found some interesting clues
that the situation at Baye
was also reflected by
similar enigmatic
occurrences at the very
place cited originally as
the type locality for the
Pandan Formation, not only
from the report of Dr. Balce,
but also from those of
Japanese and German
geoscientists, which
therefore leads us to the
conclusion that the Pandan
and Baye form one integrated
unit whose age, in the
absence of confirmatory
determination of unreworked
matrix material, should be
Late Eocene to Early
Oligocene and not Cretaceous
as heretofore believed by
all previous workers in
central Cebu.
The
Pandan seems to correspond
to the Tabgon Flysch and the
Ragas Point Olistostrome in
Caramoan Peninsula, Bicol
region, which were dated
latest Middle Eocene to
earliest Late Eocene from
nanofossils found in matrix
materials (David, 1994).
Although McCabe (1985) cited
Cebu as a good example of a
stratigraphic terrane which
he included in his Central
Philippine Arc Terrane, our
real situation conforms more
to the characteristics of a
Disrupt Terrane. This would
therefore greatly minimize
the chances of finding
Cretaceous rock units that
are truly inplace in the
known basement areas of
central Cebu.