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Geology F795 > Corals > Flashcards

Flashcards in Corals Deck (16):
1

Phylum and class

Cnidaria,
Anthozoa

2

Skeleton

Calcium carbonate, modern aragonite, fossil calcite, more stable

3

Describe morphology of a coral

Polyp is soft bodies organism, secretes calcium carbonate skeleton, corallum is whole skeleton, may be solitary or colonial

4

What are septa?

Vertical plates, radially dividing corallite skeleton, may be major or minor and give skeleton strength

5

What are dissepiments?

Curved plates connected to septa and tabulae

6

What are tabula?

Horizontal plates dividing the skeleton

7

What morphological features are present in Rugose?

Extinct, either solitary or colonial. Epithets wrinkled in solitary, horn shaped. Large, no mural pores plane of bilateral symmetry vertically
Distinguished by septa, initially 6 new septa added in spaces.
Always have columella, may have dissepiments

8

What are the morphological features of tabulate coral?

Extinct, colonial, developed tabulae. Usually small, mural pores may be present. Radial summery, may have dissepiments, no columella

9

Why are the morphological features of tabulate corals?

Solitary or colonial, form reefs today. Small, no mural pores, radial symmetry six primary septa are distinct, evenly distributed

10

Rugose:
Geological range?
Tabulae?
Corralites?
Dissepiments?
Symmetry?
Columella?
Septa?
Colonial/solitary?
Mural pores?

Ordivician-Permian
Always
Large
May be present
Bilateral symmetry
Always
6 Major septa, 4 sets of minor
Either
None

11

Tabulate:
Geological range?
Tabulae?
Corralites?
Dissepiments?
Symmetry?
Columella?
Septa?
Colonial/solitary?
Mural pores?

Cambrian-Permian
Yes
Small
None or poor
Radial
Not present
Poor or none
Colonial
May be present

12

Sclerectinian:
Geological range?
Tabulae?
Corralites?
Dissepiments?
Symmetry?
Columella?
Septa?
Colonial/solitary?
Mural pores?

Triassic-now
Always present
Many small
Always
Hexagonal radial
May be present
6 major septa, evenly spread
Either
None

13

What is the mode of life of corals?

Some have algae in symbiotic relationship- zooxanthellae, photosynthesise, waste used by corals, waste from corals used by algae.

14

What is the soft tissue of a coral?

Soft tissue not preserved, polo, sits on top it secretes skeleton, or calicehas tentacles, extend for feeding with stinging cells, or trapped in mucus, passed to mouth, into guy, waste removed from mouth

15

What conditions are required for good coral growth?

Can be found in all seas but reef are specific
30 degrees north and south of equator
At or just below sea level, photic zone
Clear waters for sunlight
Water free from particles that may clog
High energy levels for oxygen
Fully marine salinity 30-40
Temp between 23 am 27

16

How are modern reefs formed?

Fringing reef meets land, above sea level at low tide
Barrier reef out at sea with lagoon separating
Atolls or coral islands ringed shapes offshore around subsiding volcanoes
Thick was if reef increases over time to form massive unbedded reef limestone