Fracture Zones of Pacific Northwest
1600 to 3300 miles (60 miles wide)
(Fracture zones)
Sea Mountains & Volcanoes
H20 500 fathoms deeper south of Fracture Zone
Coral Reefs: Tropical Regions,
Calcareous plants and animals
6000 miles in Pacific Northwest to Southeast
15 00 miles under
Outside of Pacific Sejchilles/Maldive
Bermuda in the Atlantic Ocean
Relatively low elevation
Lagoon & atoll assoriaton
Fishing areas
Types of Reefs:
(1) Fringing
(2) Barrier
(3) Atoll
(4) Table
(5) Oval reef inside Atoll
Fringing reefs: border islands coasts (Hawaii - 1 mile under)
Channel from land - can be deep (channel/ parts of fringing reef in more instances
- graves well and quickly because of salinity.
Atoll: reef encloses Island (example: Eniwitok)
(Ring around irregular shaped)
Table Reef: shallow - hazard to navigation (Washington Island near Hawaii)
North of Equator
Oval reef: needs good from atoll (patch reef, knoll or)
Great Barrier Reef of Australia: 1500 * 100 / Largest in the Word
Darwin Submerging Coast vs. Daly Glacier
Charles Darwin - Beagle Voyage 1835 subsiding volcano uphill coral
Characteristics of Coral Reefs:
(1) Rocky mound: platforms or ridges
(2) Slightly elevated
(3) Coral mass skeletons
(4) Branching coral holds it all together
(5) Lime sheering plateau
(6) Lithothomium (encrusting Algae)
(7) Coral Reef is not solid
(8) Boring Organism (mollusk, ect.) can destroy reef
For Coral Reef to Survive:
(1) Minimum temperature 61-65 degrees F
(2) Max temperature 96 degrees F
(3) Depth Max 150 feet (some (few to) 580 feet)
(4) Saline H2O: 27 to 40 pph
(5) Mud clear H20
(6) Wenduard Islands have better coral growth