1 / 10

SEDIMENTARY ROCKS

SEDIMENTARY ROCKS. MUDROCKS. SEDIMENTARY ROCKS. Mudrocks:. 2/3 of all sedimentary rocks, but poorly understood: not very resistant too damn fine-grained clays change composition. SEDIMENTARY ROCKS. Mudrocks:. Color: gray to black – free carbon, reducing environment

macy
Télécharger la présentation

SEDIMENTARY ROCKS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SEDIMENTARY ROCKS MUDROCKS

  2. SEDIMENTARY ROCKS Mudrocks: • 2/3 of all sedimentary rocks, but poorly understood: • not very resistant • too damn fine-grained • clays change composition

  3. SEDIMENTARY ROCKS Mudrocks: Color: gray to black– free carbon, reducing environment red– ferric oxide brown- ferric hydroxides green– unstained, color of clay minerals

  4. SEDIMENTARY ROCKS Mudrocks: Texture: grain size and sorting by nibble method roundness and shape by assumption: qtz always angular, clays tabular

  5. SEDIMENTARY ROCKS Mudrocks: Structure: fissility – property of breaking along thinly spaced planes parallel to bedding flocculation? compaction? lamination – layer within, parallel to bed lamina < 1 cm; bed > 1 cm

  6. SEDIMENTARY ROCKS Mudrocks: • Composition: • first approach by nibble method • petrographic scope – resolution .5 – 1 µm; • sodium bisulfate fusion – qtz vs K-spar • X – Ray diffraction • SEM & microprobe

  7. SEDIMENTARY ROCKS Mudrocks: • Composition: • Clays • montmorillonite – Na, Ca clay, most abundant in young rocks • illite – K – clay found in older rx; 4km, 100°C • kaolinite – 3rd in abundance; hot, wet climates

  8. SEDIMENTARY ROCKS Mudrocks: • Composition: • B.Quartz • 30% of average mudrock • mostly silt • always angular • detrital vs. secondary?

  9. SEDIMENTARY ROCKS Mudrocks: • Composition: • C. Feldspar • about 5% of average mudrock • not much known • surprising to exist in such small size • secondary?

  10. SEDIMENTARY ROCKS Mudrocks: • Composition: • D. Others • carbonate – calcite common cement, dolomite common in older rx • pyrite • hematite • organic matter

More Related