Abstract:
As
the
only
low-latitude
connection
between
ocean
basins,
the
Indonesian
Throughflow
allows
the
direct
transmission
of
heat
and
salinity
between
the
Pacific
and
Indian
Oceans.
The
Mg/Ca
and
δ18O
of
calcite
of
Globigerinoides
ruber
(G.
ruber)
were
used
to
estimate
the
sea
surface
temperature
(SST)
and
δ18O
of
water,
an
indicator
of
hydrologic
conditions,
over
the
past
20,000
years.
I
also
attempted
to
estimate
thermocline
structure
using
Pulleniatina
obliquiloculata,
but
the
Mg/Ca
and
δ18O
of
calcite
data
yield
conflicting
interpretations,
indicating
further
work
on
this
proxy
is
required.
The
G.
ruber
Mg/Ca
results
suggest
that
the
SST
of
the
outflow
passages
were
influenced
by
high
latitude
Southern
Hemisphere
temperature.
At
approximately
10,000
years
before
present,
there
was
a
warming
in
the
Makassar
Strait.
This
local
warming
was
coincident
with
the
flooding
of
the
Sunda
Shelf,
which
opened
a
connection
between
the
South
China
Sea
and
the
Indonesian
Throughflow.
Regional
δ18O
of
seawater
reconstructions
suggest
that
the
mean
position
of
the
Intertropical
Convergence
Zone
(ITCZ)
was
approximately
the
same
as
modern
at
the
last
glacial
maximum
and
was
displaced
to
the
south
during
the
Younger
Dryas
and
Heinrich
Stadial
1,
suggesting
the
ITCZ
responds
to
changes
in
the
interhemispheric
temperature
gradient.
