Class Notes (836,215)
Canada (509,690)
EARTHSC 1G03 (139)
Lecture

Chapter 11 - Geologic Structures

3 Pages
105 Views
Unlock Document

Department
Earth Sciences
Course
EARTHSC 1G03
Professor
Maureen Padden
Semester
Fall

Description
CHAPTER 11 - GEOLOGIC STRUCTURES CAUSES OF ROCK BREAKAGE AND BENDING Stress and Strain in Lithosphere: Tectonic forces cause rock deformation – causing change in orientation, location, and shape.  Stress is measurable force per unit area at a point  Strain is change in size (volume) and/or shape Forces: Compressive Tensional Shear Pushed in f/ opp. Sides Pulled f/ opp. Sides - Causes shortening - Causes stretching or breaking Convergent zones Divergent zones Tranform zones Rocks Response:  Elastic: deformed material recovers original shape after stress is reduced/removed o Elastic limit: the limit to which rock can bend before damage is permanent  Ductile (plastic): bends under stress and remains as such o Permanent damage due to folding or bending of rock layers o Folds: permanent wavelike deformations in layered rocks  High temperatures and pressures  Brittle: rock breaks under stresses o Result in faults or joints; fault: fracture in bedrock along which rocks on one side move/displace relative to the other side  Joint (or joint sets): fracture/crack in bed rock w/o displacement o Compressive forces cause: reverse faulting o Tensional forces cause: faulting o Shear forces cause: strike-slip faulting Rocks response influenced by: stress type, rock type, temperature, pressure, fluids, length and magnitude of stress applied. MEASURING AND RECORDING GEOLOGIC STRUCTURES GEOLOGIC MAPS  Uses standardized symbols and patterns to represent rock types and geologic structures  Geologic maps show the type and distribution of rock types, structural features, ore deposits, etc.  Data obtained either from ground or from remotely sensed data f/ a satellite or airplane STRIKE AND DIP  Sedimentary beds can be deposited as horizontal beds or strata  Tilted due to deposition and lithification  Strike: compass direction of a line formed by intersection of inclined plan and horizontal plane (customarily north)  Angle of dip: measured downward from horizontal plane to the inclined plane  Direction of dip: direction in which the angle of dip is measured GEOLOGIC CROSS-SECTION  Represents vertical slice through portion of Earth GEOLOGIC STRUCTURES FOLDS Fold: bends or wavelike features in layered rock. Fold geometry:  Anticline: upward-arching fold o Oldest layers in middle  Syncline: trough-like fold; downward arching o Youngest layers in middle  Limb: fold contains two limbs – l
More Less

Related notes for EARTHSC 1G03

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit