Readings from Sediments & Basins: (8:1-67) Sedimentary Geology Geos 240 – Chapter 8 Depositional Environments Part 1 Introduction, Fluvial & Coastal Dr. Tark Hamilton Readings from Sediments & Basins: (8:1-67) Camosun College

Great Barrier Back Reef, Queensland Branching Corals & Carbonate Sand

Depositional Environments

The Peace River, Ft. St. John, NE B.C.

Gravel-Sand-Silt-Clay Four Decreasing Gradient: 1>2>3>4 2 3 4 Gravel-Sand-Silt-Clay 1

Sandy Braided River Model Based on South Saskatchewan Bars Persist for decades Flow & Aggradation Lateral Aggradation

Anastomosed River Model Based on Cumberland Marshes, East Central Saskatchewan-Manitoba Stable Vegetated Marsh Flow Direction, Channel Sands Crevasse Splay Deposit

Cutbank, Upwards Fining, Cenozoic

Narrow Sand Body, Permian Anastomosed River, NM

Point Bar Sand with Lateral Accretion & Mud Fill

Cutbank, Arid Fluvial Sys. AZ

Cutbank, Arid Fluvial Sys. AZ

Cutbank, Carboniferous Channel Sand, KY Collapsed & Rotated Block Of Sandstone that fell Into the Channel

Cutbank, Sand on Sand, Jurassic AZ

Box Canyon Cut into Basal Triassic Unconformity AZ

Box Canyon Cut into Basal Triassic Unconformity AZ

Caliche Paleosol, Triassic Redbeds, Spain

Caliche Paleosol, Triassic Redbeds, Spain

Interbedded Floodplain Siltstones & Musdtones w/Channel

Thin Floodplain Muds over Sheet Sand, Devonian, Arctic Canada Upwards Fining

Modern Ergs: Eolian Deserts Tropic of Cancer & Capricorn ~25°N & S (Why Here?) Continental Interiors & Rainshadows (Find 2)

Facies Model for an Erg (Desert)

Cyclic Stratigraphy of Dunes Climate, Sea Level, WT Change MBS: Deflation, Lags, Ventifacts, Desert Varnish, Blow Outs, Downlap

Stream (WT) Cutting Dunes, Colorado

Interdune Pond: Mudcracks w/Silt, Gobi

Slumped Bed on Face of Dune, Navajo Sandstone, Arizona

The Barchan Dune that ate the Truck, Gobi

Deflation Surface Ventifacts w/Desert Varnish Gobi

Deflation Surface Comet Marks: Sand in Lee, Gobi

The Ventifact: Wind Faceted Stone

Deflation Surface w/Ventifacts, Triassic Spain

Deflation Surface w/Ventifacts, Permian Scotland

Lacustrine Deposits

Lacustrine Oil Shales Green River Fm, Eocene WY

Varved Glacio-lacustrine Clay/Silt, Pleistocene, ON Dropstone (see notes) Compression and piercing of beds beneath the dropstone, drape above it.

Hypothetical Coastal Depositional System Facies

South Carolina Barrier Islands Spit Bars, Tide Flats

South Carolina Barrier Islands Estuary

Galveston Island & Matagordia Bay, Texas What are the green curves? What is this feature?

Dune & Beach, South Padre Island (Galveston, Texas)

Turbulent Dispersion of Shelf Muds after Hurricane Ida MODIS 10/10/09 Hurricane Ida came ashore to the east making landfall in Alabama and Florida a few hours earlier. This sediment dispersion and re-suspension is due to wind and waves outside of the main storm area! Secondary sediment sources are the brown muds from the Mississippi (middle right edge) and coastal erosion of mud and sand near shore. The green colour is due to phytoplankton blooms enhanced by fertilizer runoff: nitrates, iron etc. http://earthobservatory.nasa.gov/IOTD/view.php?id=41237 Ida’s Path See Notes

The End of Part 1!