Historical geology

Question 1

Explain law of superposition, law of original horizontality, law of lateral continuity, and law of cross-cutting

Answer 1

Law of superposition:
in an undeformed rock sequence, older yung sa pinakababa
Law of original horizontality:
original configuration of rock sequence is horizontal
Law of lateral continuity:
rock layers will extend outwards until disturbed
Law of cross-cutting:
kapag may may nagcut sa rock sequence (fault or intrusions), older yung rock kaysa sa layer na nagcut it

Question 2

Explain the concept of inclusion

Answer 2

Kapag may intrusion sa rock mo, older yung intrusion na yun (the body which hosts it)

Question 3

Explain unconformities and its types

Answer 3

unconformities: breaks in the deposition of the rock (either long periods of non-deposition or erosion)
Angular conformity: may dip then nagdeposit yung rock
Nonconformity: nagdeposit yung rock sa igneous/metamorphic body
Disconfomity: may long period na break bago nagdeposit ulit yung rocks pag disconformity, it points to period of erosion pag paraconformity it points to period of non-deposition

Question 4

Explain principle of faunal succession

Answer 4

any time period can be recognized through its fossil content

Question 5

Explain correlation

Answer 5

Correspondence ng dalawang geographically separated parts of a geologic unit which is based on the similarity ng lithologic and paleontologic features

Question 6

Absolute dating

Explain radiometric dating

Answer 6

technique used to determine the age of rocks based on the abundance of n-o radioactive isotope and its decay products using its decay rates

Question 7

What are the two main epochs?

Answer 7

Precambrian and phanerozoic

Question 8

Phanerozoic epoch is further divided into three eras, what are those and give the significant events.

Answer 8

Paleozoic - cambrian explosion
Mesozoic - dinosaur (jurassic period)
Cenozoic - primates -> mammals -> humans

Question 9

What era and period are we in?

Answer 9

Quaternary, Holocene

Question 10

In fossils we have:
unaltered body part
chemically altered body part
imprints of hard parts

Answer 10

unaltered body part - bones, shells (mummification of soft tissues)
chemically altered body part - thin carbon film
imprints of hard parts - molds and clasts

Question 11

amber fossil
impression and carbon film
burrows and tracks
gastroliths

Answer 11

amber fossil (protective cover/preserving medium)
impression and carbon film (carbonization)
burrows and tracks - ichnofossils
gastroliths - rocks found in dinosaurs