Sedimentary Rock Descriptions and Distractions
description
Transcript of Sedimentary Rock Descriptions and Distractions
Sedimentary Rock Descriptions and Distractions
• Description vs Interpretation
• Rock Descriptions
• Unit Descriptions
• Distractions
Text: Manual, p. 13-16, 77-90; Compton, p. 27-31
Rock Descriptions
• rock type
• stratigraphic name
Rock Descriptions
• stratigraphic name
• rock type
• color
(Luis Garcia)
Rock Descriptions
• stratigraphic name
• rock type
• color
• texture
Rock Descriptions
Texture: 1. Grain Size
256 -8 boulder64 -6 cobble gravel4 -2 pebble2 -1 granule _______1 0.0 very coarse sand0.5 1.0 coarse sand0.25 2.0 medium sand sand0.125 3.0 fine sand0.0625 4.0 very fine sand _______0.031 5.0 coarse silt0.0156 6.0 medium silt mud0.0078 7.0 fine silt0.0039 8.0 very fine silt clay
mm Phi () Wentworth Size Class
angular grains
well rounded grainshttp://csmres.jmu.edu/geollab/Fichter/SedRx/
Rock Descriptions
Texture: 2. Grain Shape (Roundness)
Rock Descriptions
Texture: 3. Sorting
(AGI, 1999)
Rock Descriptions
Texture: 4. Arrangement
imbrication
• energy/environment of deposition
• transport history
Rock Descriptions
Texture Interpretations
Rock Descriptions
• stratigraphic name
• rock type
• color
• texture
• grain composition
Rock Descriptions
• stratigraphic name
• rock type
• color
• texture
• grain composition
• porosity
• cements
grain
porosity
matrix
cement
(M. Campbell)
Rock Descriptions
Rock Descriptions
• name
• rock type
• color
• texture
• grain composition
• porosity
• cements
• bedding
Rock Descriptions
Bedding: Types
Castile Formation, NM (Anderson et al., 1972)
10 cm
laminations
Rock Descriptions
Bedding: Types
cross-bedding
Rock Descriptions
Bedding: Types
graded bedding
(AGI, 1999)
Rock Descriptions
Bedding: Thickness
Rock Descriptions
Bedding: Contacts
Rock Descriptions
• stratigraphic name
• rock type
• color
• texture
• grain composition
• porosity
• cements
• bedding
• sedimentary structures
wave ripples
Rock Descriptions
Sedimentary Structures
Rock Descriptions
burrows
Sedimentary Structures
Rock Descriptions
Sedimentary Structures
mudcracks
(AGI, 1999)
Rock Descriptions
• stratigraphic name
• rock type
• color
• texture
• grain composition
• porosity
• cements
• bedding
• sedimentary structures
• bioturbation
Rock Descriptions
Bioturbation
(E. McBride)
Rock Descriptions• stratigraphic name
• rock type
• color
• texture
• grain composition
• porosity
• cements
• bedding
• sedimentary structures
• bioturbation
• fossils
Trace Fossils
Rock DescriptionsFossils
Body Fossils
Cretaceous fossils in central Texas
http://www.cretaceousfossils.com
Rock Descriptions
Fossils
UTAUSTIN
Interpretation
Rock Descriptions
Additional Details for Sandstones:
- FMCP:QFR
- Clan Name
Rock Descriptions
Sandstone Clan Names
Sedimentary Rock Descriptions and Distractions
• Description vs Interpretation
• Rock Descriptions
• Unit Descriptions
• Distractions
Text: Manual, p. 13-16, 77-90; Compton, p. 27-31, 366-367
Unit Descriptions
• stratigraphic name
• rock types
• brief rock descriptions
- percentages- thicknesses
- contacts- interbedding
• special features
- soil and vegetation- topographic expression
gradational
sharp
interbedding
Unit Descriptions
bench
slopecliff
Sedimentary Rock Descriptions and Distractions
• Description vs Interpretation
• Rock Descriptions
• Unit Descriptions
• Distractions
Text: Manual, p. 13-16, 77-90; Compton, p. 27-31, 366-367
Distractions
Vegetation
(Luis Garcia)
Distractions
Algae
Distractions
Lichen
Distractions
Travertine
(E. McBride)
Distractions
Weathering
Distractions
(E. McBride)
Colluvium
Distractions
Float
(E. McBride)
Distractions
Dynamite
(E. McBride)