Tuning the CARIS implementation of CUBE for Patagonian Waters.pdf

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3.1.1 North Patagonia Area.
The geomorphology in this area can be explained mainly by differences according
to the piedmont’s width. Thus the fjord’s depth is directly proportional to the width of
this trench.
This area can be spilt into three sectors, delimited by the Jacaf Channel and the
Reñihue Fjord (Figure 3.1). Their differences are regulated by the absence or presence of
fjords. For example, in the north and south sectors (with presence of fjords), in general
the sea bottom is very irregular. Extreme changes in depth are predominant in the fjords,
where glacial deposits, such as moraines and drumlins, are observed. The basins have an
accumulation of sediments (20 to 100 metres in thickness), highly stratified and
acoustically weakly reflecting (Figure 3.2). On the other hand, the central area (without
fjords) has a piedmont mostly intact and regular with a layer of sediments made by
physical weathering action (i.e., breakdown of rocks and soils with direct atmospheric
contact such as water and pressure).
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(m) depth
Costa Channel
Deflated tills
Ponded
Ponded
0 10 Km Aysen Fjord
Figure 3.2: The flat bottom areas are compound by sediments with a thickness of 30 to 60
metres called Ponded (i.e. Fine-grained post glacial mud). The contrast is so strong with
the high backscatter signal of deflated Tills (i.e. boulders and rock outcrop) that it can
result in failures in the sea bottom tracking. From (Araya [1996]).
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