Exam 3 - Geol 101 - pt 1

What is the principle of original horizontality in stratigraphy?

Rocks are deposited horizontally.

Define the principle of superposition.

In undisturbed rocks, the oldest layers are at the bottom and the youngest are at the top.

What do cross-cutting relationships tell us about rock formations?

Features that cut across rocks are younger than the rocks they cut.

What are inclusions?

Rock fragments contained within another rock, indicating they are older than the rock they are in.

Half-life definition.

The amount of time needed for half of the atoms of the parent isotope to decay to the daughter isotope.

What is an unconformity?

A surface representing a period of time where deposition stopped and erosion occurred.

What type of unconformity is defined as a surface between two parallel sedimentary layers?

Disconformity

What characterizes angular conformity?

A surface between two non-parallel sedimentary layers

What are the conditions needed for fossilization?

Hard parts, low-energy environment, burial quickly, and sedimentary rocks.

Define a good index fossil.

Organisms that succeeded one another in a definite and determinable order.

What is the atomic number?

The number of protons in the nucleus of an atom.

Differentiate between brittle and ductile deformation.

Brittle deformation involves fracture with movement on either side, while ductile deformation involves bending without breaking.

What is normal fault?

A dip-slip fault where the hanging wall moves down relative to the foot wall.

Define right-lateral strike-slip fault.

A strike-slip fault where the opposite side moves to the right.

What do anticlines and synclines represent in terms of rock layering?

Anticlines have the oldest rocks at the center, while synclines have the youngest rocks at the center.

What is the effect of compression on rock deformation?

It causes squeezing, shortening, and thickening of rock layers.

What is the significance of the geologic time scale in geology?

It represents the timeline of Earth's history and the sequence of geological events.

How can half-life be used to date rocks?

By measuring the percentage of parent and daughter isotopes, the age of a rock can be calculated.

What are the characteristics of a strike-slip fault?

They result in horizontal movement and are associated with transform boundaries.