Sedimentary Rock Descriptions and Distractions Description vs Interpretation











































- Slides: 43
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 • stratigraphic name • rock type
Rock Descriptions • stratigraphic name • rock type • color
(Luis Garcia)
Rock Descriptions • stratigraphic name • rock type • color • texture
Rock Descriptions Texture: 1. Grain Size mm 256 64 4 2 1 0. 5 0. 25 0. 125 0. 0625 0. 031 0. 0156 0. 0078 0. 0039 Phi ( ) -8 -6 -2 -1 0. 0 1. 0 2. 0 3. 0 4. 0 5. 0 6. 0 7. 0 8. 0 Wentworth Size Class boulder cobble pebble granule very coarse sand medium sand fine sand very fine sand coarse silt medium silt fine silt very fine silt clay gravel _______ sand _______ mud
Rock Descriptions Texture: 2. Grain Shape (Roundness) angular grains http: //csmres. jmu. edu/geollab/Fichter/Sed. Rx/ well rounded grains
Rock Descriptions Texture: 3. Sorting
Rock Descriptions Texture: 4. Arrangement imbrication (AGI, 1999)
Rock Descriptions Texture Interpretations • energy/environment of deposition • transport history
Rock Descriptions • stratigraphic name • rock type • color • texture • grain composition
Rock Descriptions • stratigraphic name • rock type • color • texture • grain composition • porosity • cements
Rock Descriptions grain porosity cement matrix (M. Campbell)
Rock Descriptions • name • rock type • color • texture • grain composition • porosity • cements • bedding
Rock Descriptions Bedding: Types 10 cm laminations Castile Formation, NM (Anderson et al. , 1972)
Rock Descriptions Bedding: Types cross-bedding
Rock Descriptions Bedding: Types (AGI, 1999) graded bedding
Rock Descriptions Bedding: Thickness
Rock Descriptions Bedding: Contacts
Rock Descriptions • stratigraphic name • rock type • color • texture • grain composition • porosity • cements • bedding • sedimentary structures
Rock Descriptions Sedimentary Structures wave ripples
Rock Descriptions Sedimentary Structures burrows
Rock Descriptions Sedimentary Structures (AGI, 1999) mudcracks
Rock Descriptions • stratigraphic name • rock type • color • texture • grain composition • porosity • cements • bedding • sedimentary structures • bioturbation
Rock Descriptions Bioturbation (E. Mc. Bride)
Rock Descriptions • stratigraphic name • rock type • color • texture • grain composition • porosity • cements • bedding • sedimentary structures • bioturbation • fossils
Rock Descriptions Fossils Trace Fossils Body Fossils
Rock Descriptions Fossils Cretaceous fossils in central Texas http: //www. cretaceousfossils. com
UT AUSTIN 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 interbedding • brief rock descriptions - percentages thicknesses contacts interbedding • special features - soil and vegetation - topographic expression gradational sharp
Unit Descriptions cliff slope bench
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
Distractions Algae (Luis Garcia)
Distractions Lichen
Distractions Travertine
Distractions Weathering (E. Mc. Bride)
Distractions Colluvium (E. Mc. Bride)
Distractions Float (E. Mc. Bride)
Distractions Dynamite (E. Mc. Bride)