4.2 Phase II: Mid-Upper Depths (GC1: 0-202 cm, GC2: 0-202 cm and
GC3: 0-202 cm)
These depths cover the middle to the upper parts of the three GCs and
are characterised by a slower sedimentation rate of mudstone, expansion
of mangrove vegetation (~60-80% Rhizophora sp.
and 25-30% Avicenniaceae), high Fe/S ratio (Table 1), and increase in
planktonic foraminifera (~60-79 % Globorotaliaspp.). These depths also record fewer hinterland pollen (e.g.,
~10-20% Poaceae, 0-5% Podocarpus ,
~7% Cyperaceae, 0-4% charred grass
cuticles), 2-5%Pediastrum , low Ti/Zr ratio, and higher sedimentation rate of
very fine-silty sand (GC1 = 78.2 cm/kyr; GC2 =
57.3 cm/kyr; GC3 = 57.3 cm/kyr)
(Table 1). During this interval of rapid expansion of mangrove-dominated
pollen, hinterland pollen and other components (e.g., Ti/Zr, cuticles)
dramatically decline when compared to the lower depths (Figures 3-5).