Transcript Chapter 5: Rocks

Section 4: Rocks from Reefs
CHAPTER 5: ROCKS
CORAL REEFS

Structure of calcite (calcium carbonate - CaCO3)
skeletons built up by coral animals in warm, shallow
ocean water
HOW CORAL ANIMALS LIVE


Most are smaller than your fingernail
Tiny algae grow within body and provide substances
that the coral needs to live; coral provides structure to
algae
BIOLOGY CONNECTION

What type of relationship do the coral animal
and algae have?
BIOLOGY CONNECTION
What type of relationship do the coral animal
and algae have?
 A symbiotic relationship

HOW A CORAL REEF FORMS
Coral animal skeletons made when they absorb
Ca from water and combine it with C and O to
form calcite
 When animals die, skeletons remain
 More corals build on top of them, gradually
forming a reef

CHECKPOINT 1

How do coral reefs form?
CHECKPOINT 1
How do coral reefs form?
 The calcite skeletons of coral animals remain
after the animals die and then more build up
on top of them.

WHERE CORAL REEFS FORM
Within 40 meters of water’s surface because
algae needs sunlight
 Warm water of tropical oceans
 US: Florida & Hawaii
 Australia – Great Barrier Reef

CHECKPOINT 2

If sea level rises above a coral reef, what may
happen to the reef?
CHECKPOINT 2
If sea level rises above a coral reef, what may
happen to the reef?
 If sea level rises slowly, the reef might build
upward. If sea level rises too quickly, the reef
could die.

LIMESTONE FROM CORAL REEFS
Coral reef = organic limestone
 Limestone deposits that began as reefs provide
evidence of how plate motions have changed
Earth’s surface and of past environments

 Ex.
Wherever there were reefs, there were once a
warm climate and shallow ocean water (Midwest &
Southwest US)
CHECKPOINT 3

A geologist finds an area abundant in
limestone. What can the geologist infer about
that area?
CHECKPOINT 3
A geologist finds an area abundant in
limestone. What can the geologist infer about
that area?
 S/he can infer that at the time when the
limestone formed, the area was in a warm
climate and was covered by shallow ocean
water.

POST-LESSON QUIZ
1.
Which element does not make up a coral reef?
a. calcium
b. carbon
c. boron
d. oxygen
POST-LESSON QUIZ
2. How do coral reefs form?
a. coral plants die and their stems form the
reef
b. coral animals die and their skeletons
form the reef
c. algae hardens and crystallizes
d. rock sediment compacts and cements
together
POST-LESSON QUIZ
3. Which of the following is not something that
corals need to live?
a. deep water
b. sunlight
c. algae
d. warm water
POST-LESSON QUIZ
4. What type of rock does coral reef form?
a. clastic limestone
b. clastic sandstone
c. organic sandstone
d. organic limestone
POST-LESSON QUIZ
5. Remains of a coral reef provide evidence of
which of the following?
a. the climate in that area was warm and
covered in water
b. the climate in that area was cold and dry
c. the climate in that area was cold and wet
d. the climate in that area was warm and
dry