Themes of the Day:

• Clastic Sedimentary Rocks Classification
• Conglomerates
• Sandstone Classification
• Sandstone Diagenesis

Clastic Sedimentary Rocks Classification

• Grain size subdivisions
• Phi = log₂mm
• Conglomerates
  • oligomictic - all clasts of the same composition
  • polymictic - variety of clast compositions
  • in provenance studies - Poway clasts (chemical comparison) - Gualala conglomerates
• Gualala, CA Region Turbidites
  • Basin Strat Column
  • Seacliffs Overview
  • Same outcrop as a Gigapan
  • Bouma Sequence 1
  • Bouma Sequence 2
  • Turbidites
  • Large Boulder
  • Conglomerates with Starfish
• Other Conglomerates
  • Point Lobos, CA
  • Point Lobos, CA Gigapan
  • Point Lobos, CA Gigapan - a different view
  • Fluvial Conglomerate, Kings Canyon, CA
  • Interlayered with Basalt flows, Keeweenawan Rift, Ontario
  • Another view, Keeweenawan Rift, Ontario
  • Sedimentary Breccia (anthropogenic?)
  • Alluvial fan/Fluvial conglomerates, Eastern California
  • Quaternary fanglomerate near Bisbee, AZ
  • Conglomerate, Southern Henry Mountains
  • Imbricated clasts, Death Valley NP
  • Sedimentary Breccia, Mosaic Canyon, Death Valley NP
  • Volcanic Breccia, Montezuma Pass, Arizona

Clastic Sedimentary Rocks Classification

• Grain size subdivisions
• Phi = -log₂mm
• Angularity and Sphericity
• Sandstones
  • Primary Components: Quartz, Feldspar, Lithic Fragments
    • How abundant are these components in: a) igneous rocks, b) metamorphic rocks, c) sandstones?
  • Sandstone Classification
  • More Sandstone Classification from the Field Manual
    • USGS Checklist for Field Description of Sedimentary Rocks
    • USGS Checklist for Field Description of Sedimentary Rocks (cont'd)
    • Chart for Distinguishing the Three Classes of Rock
    • Major Sandstone Classifications
    • Clast Size Scale
    • More Size and Shape info
    • Even More Classification Triangles
    • Clastic Bedforms
    • Yet More Classification Info
  • Secondary Components: Heavy minerals, other accessory minerals - e.g., variteies of garnet in heavy mineral separate
  • Provenance Discrimination with Sandstones
  • Climatic Zones during the Jurassic
  • Effect of climate on sandstone composition
  Sediment evolution during weathering
• Mudstones
  • siltstones - gritty on teeth
  • shales - smooth on teeth

Sandstone Diagenesis

• Compaction & Cementation - friable to quartzite
• Quartz Cement
• Calcite Cement
• Hematite Cement
• Clay Mineral Cement
• Zeolite Cement
• Albitization
• Calcitization
• Plate Tectonic Controls