Types of Unconformities

अब Quizwiz के साथ अपने होमवर्क और परीक्षाओं को एस करें!

What is a disconformity?

A disconformity is a minor irregular surface separating parallel strata on opposite sides of the surface. Sedimentary layers are deposited, then the deposition stops and the layers are eroded. After a period of erosion, new sedimentary layers are deposited again.

What is a fault?

A fault is a fracture in the rock. The rocks on both sides of the fault have moved.

What is a joint?

A joint is a fracture/crack in the rock. The rocks on both sides of the joint do not move

What causes a joint?

A joint may be due to compression, tension or shear stress. A joint is a form of brittle strain

What is a nonconformity?

A nonconformity is a break surface that developed when igneous or metamorphic (not sedimentary layers) rocks were exposed to erosion, and younger sedimentary rocks were subsequently deposited above the erosion surface.

What is an angular unconformity?

An angular unconformity is a tilted or folded sedimentary rocks that are overlain by younger, more flat-lying strata. Layers were deposited, then deformed or tilted and then eroded. New layers were deposited on top of the eroded surface.

What is an unconformity?

An unconformity is a surface between strata layers that represents a break in the time record. It results from an interval when deposition was interrupted or stopped for a while. Then, the top of the layer was eroded and then deposition began again, forming more new layers.

What causes a fault?

Caused by tension or compression

How can a unconformity be identified in cross section?

In a cross section, an unconformity can be identified by a wavy, eroded layer.

How do joints occur?

Joints occur in sets, not alone as a single joint -- usually parallel joints.

Unconformity

Surface that represents a break in the rock record

What are the three main types of unconformities?

The three main types of unconformities are: Disconformity Angular unconformity Nonconformity

What evidence must there be for a fault?

To be a fault, there must be evidence that the rocks have moved on both sides of the fault Other evidence is: Crushed rock found in the fracture The sides of the fault have been polished smooth and may have striations (grooves) on them due to the rocks rubbing past each other The features on the ground or man-made features (like a fence) have moved from their original positions

Disconformity

When an underlying and overlying sedimentary rock strata are parallel and the contact plane is an erosional surface

Angular Unconformity

When an underlying rock and an overlying rock strata show some angle

Nonconformity

When underlying rocks are igneous or metamorphic and the overlying rocks are sedimentary

Unconformity

gap in the rock layer that is due to erosion or periods without any deposition.

Disconformity

layer of horizontal rock once exposed and eroded before younger rocks formed over it

Angular Unconformity

rock layers are tilted, and younger sediment layers are deposited horizontally on top of the eroded and tilted layers.

Nonconformity

sedimentary rock forms over eroded metamorphic or igneous rock


संबंधित स्टडी सेट्स

MGT 4110- Chp 5 Background Checks

View Set

Personal and Community Health Exam 2

View Set

MKTG 301 Ch. 9 Buying and Disposing

View Set

D072: Module 9, D072: Module 8, D072: Module 4, D072: Module 5, D072: Module 1, D072: Module 2, D072: Module 7, D072: Module 3, D072 Key Concepts

View Set

Chapter 6 Wireless Networking Terms

View Set

(190e20-3) Overview of TCP/IP Applications

View Set