The Ocean Basin Flashcards
What is the composition of Oceanic crust
silicate with iron (heavier)
What is the composition of Continental crust
silicate with aluminum (lighter)
What is another name for oceanic crust
basalt
what is another name for continental crust
granite
How old is the oldest oceanic crust
200 million years
How old is the oldest continental crust
3.8 billion years (since last rocks were melted)
What is the average thickness of oceanic crust
7 km
What is the average thickness of continental curst
40 km
What is Bathymetry
the topography of the sea floor
How much of the Earth surface is covered in water
71%
What is the mean depth of the ocean
3800 m
What is the continental shelf
gently sloping part of ocean floor adjacent to continent
What is the depth the shelf break is at
200 m
What is the slope of the continental crust
2 m for every 1 km traveled
What is the continental slope
zone between continental shelf and ocean basin
what is slope of continental slope
70 m for ever 1 km travled
What is turbidity
Suspended particles that decrease clairty
What is the continental rise
thick wedge of sediment located at base of continental slope
What is the abyssal plain
very flat region, has thick layer of sediment
What is the abyssal hills and seamounts
differs in height above sea floor, usually volcanoes, hills are extinct volcanoes
What are the mid ocean ridges and rises
volcanic subsea mountains that mark the region of crustal movement
What are trenches
steep sided depressions that mark where ocean crust is subducted into mantle
deepest part of ocean
often adjacent to volcanic island arcs
how do passive continental margins differ from active continental margins
passive- gentler slope, no volcanoes
active- steep slope, trench, volcanoes
