Geoscience Reference
In-Depth Information
Norman
Reef
N
Saxon
Reef
Hastings
Reef
Batt Reef
16
o
30' S
Outer
shelf
Middle
shelf
Trinity
Bay
Arlington
Reef
Inner
shelf
16
o
45' S
Green
Island
Core
Thetford
Reef
Moore
Reef
Core
Chenier plain
Elford Reef
Cairns
Fitzroy
Island
17
o
00' S
Sudbury
Reef
Scott
Reef
0 (km) 20
Case Fig. 10.1A
Bathymetry of the shelf near Cairns, showing inner shelf, location of cheniers, core sites on inner and mid-
shelf, and the outer shelf reef complex.
Case Table 10.1
The main sedimentary effects of cyclones across the main shelf environments of the GBR.
(Sources: Hopley 1982; Gagan et al. 1988; Nott & Hayne 2001; Larcombe & Carter 2004.)
Shelf
sedimentary
environment
Main sedimentary features
Indicated average
storm recurrence
interval (yr)
Sediment accumulation
or erosion?
Coastline
or island
perimeter
Inner shelf
Beach erosion, formation of chenier
ridges at muddy coastlines or beach
ridges at sandy coastlines
Unmix sediment, transport it along shelf,
creating large dunes of shelly gravel and a
graded bed, receive sediment from rivers
and from erosion on the middle shelf
As above plus formation of sand/gravel
ribbons
177-280 (cheniers)
Variable
120 -150 (shellbeds)
Net accumulation
Middle shelf
360 -7600 (shellbeds
at 40 m depth)
Net erosion. Sediments
exported both landward
and seaward
Net sediment accumulation
Outer shelf
As middle shelf
