Sedimentary Rock Descriptions and Distractions Description vs Interpretation

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)