Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Analysis of Folds - Structural Geology - Lecture Notes, Study notes of Geology

In these Lecture notes, Professor has tried to illustrate the following points : Analysis Of Folds, Folds, Outcrop, Fold Description, Geometry, Hinge Line, Fold Axis, Axial Trace, Vertical Fold, Parallel Fold

Typology: Study notes

2012/2013

Uploaded on 07/22/2013

seshadri_44het
seshadri_44het 🇮🇳

4.6

(48)

187 documents

1 / 2

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
1
Structural Geology Lab 6: Analysis of Folds in Outcrop
I. Lab Exercise on Fold Description and Geometry.
A. Review of Fold Terms
Hinge/ hinge line inflection point line of inflection median surface
crest/trought crestal /troughal trace cylindrical noncylindrical
fold axis symmetric/ asymmetric axial surface axial plane
axial trace synform/antiform anticline/syncline overturned
vertical fold reclined fold recumbent fold interlimb angle
parallel fold similar folds dip isogons Ramsay's Classif.
B. Drawing dip isogons
1. dip isogon: lines connecting points of equal dip between bedding planes in
a fold
2. Method 1 using protractor
3. Method 2 using two see-through drawing triangles
a. pick point on bedding plane
b. use triangle to define line tangent to point
c. slide triangle paralle itself til it touches tangent to next bedding
plane
d. make point on bedding plane 2, connect two points to form dip
isogon
e. repeat numerous times limb to hinge to limb of fold to derive set of
dip isogons
f. compare to Ramsay's visual classification system and identify
C. Looking at Folds in Cross-section
1. profile plane: best drawn perpendicular to fold axis, perpendicular to
strike of beds... i.e. looking parallel to fold axis
2. Using map patterns to see fold shape in x-sectional view
a. using strike and dip symbols, determine the type of fold being
examined in map view
b. determine if fold is plunging or nonplunging, use law of v's for
outcrop pattern
(1) determine plunge direction
c. Examine fold map pattern with an acute, oblique line of sight,
looking in a down plunge direction along the hinge trace of the
fold
Docsity.com
pf2

Partial preview of the text

Download Analysis of Folds - Structural Geology - Lecture Notes and more Study notes Geology in PDF only on Docsity!

Structural Geology Lab 6: Analysis of Folds in Outcrop

I. Lab Exercise on Fold Description and Geometry.

A. Review of Fold Terms

Hinge/ hinge line inflection point line of inflection median surface crest/trought crestal /troughal trace cylindrical noncylindrical fold axis symmetric/ asymmetric axial surface axial plane axial trace synform/antiform anticline/syncline overturned vertical fold reclined fold recumbent fold interlimb angle parallel fold similar folds dip isogons Ramsay's Classif.

B. Drawing dip isogons

  1. dip isogon: lines connecting points of equal dip between bedding planes in a fold
  2. Method 1 using protractor
  3. Method 2 using two see-through drawing triangles

a. pick point on bedding plane b. use triangle to define line tangent to point c. slide triangle paralle itself til it touches tangent to next bedding plane d. make point on bedding plane 2, connect two points to form dip isogon e. repeat numerous times limb to hinge to limb of fold to derive set of dip isogons f. compare to Ramsay's visual classification system and identify

C. Looking at Folds in Cross-section

  1. profile plane: best drawn perpendicular to fold axis, perpendicular to strike of beds... i.e. looking parallel to fold axis
  2. Using map patterns to see fold shape in x-sectional view a. using strike and dip symbols, determine the type of fold being examined in map view b. determine if fold is plunging or nonplunging, use law of v's for outcrop pattern (1) determine plunge direction c. Examine fold map pattern with an acute, oblique line of sight, looking in a down plunge direction along the hinge trace of the fold

Docsity.com

(1) in this view, you will have an apparent x-section profile of the fold, i.e. you will see true form of antiforms and synforms

Lab Exercise - Fold problems

  1. Read over material in chap. 6 of lab manual, p. 73-90. This is a very succinct review of the lecture material on folds. This will help you review for the upcoming exam.
  2. complete the following problems: 6.1, 6.2, 6.3, 6.4, 6.

Docsity.com