a 300-year multi-proxi record of paleoclimate
from a speleothem from belize
by
Eric Paul White
University
of New Hampshire
A 162.5 mm long stalagmite recovered from a cave in western Belize
dated to 294 years by 210Pb gamma spectrometry accumulated at a rate
of 0.55 mm/year and provides a detailed record of physical growth features
(e.g. lamination thickness and luminosity) and stable carbon and oxygen
isotopes. Growth lamination thickness
and corresponding calcite color of 626 alternating light and dark bands are
directly related with statistical significance.
It is suggested that laminations are semi-annual and occur in pairs
representing rainy and dry seasons.
Fluctuations in mean annual calcite color lag behind corresponding
rainfall pulses by approximately 2 years.
Stable oxygen isotopes record either hurricanes or El Niño events in the form of 1.5‰ to 2.0‰ shifts occurring on
a 4 to 10 year period. d13C
values increase by more than 5.0‰ twice in succession over the last 110 years
likely related to historical forestry practices that caused a shift in plant
species from C3 to C4 communities.
Site map
of Roaring Creek and Actun Tunichil Muknal (ATM) cave
Composite time-series of physical and
chemical stratigraphy data from 1685 – 1985
One-year moving averages of rainfall
and luminosity showing lag time, 1965-1982
d13C and Mahogany exports from 1800 to 1990 showing potential relationship
