105Lab06SedRks

105Lab06SedRks - GEOL 105 Lab 6 Sedimentary Rocks _ Week of...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
GEOL 105 Lab 6 Sedimentary Rocks ________________ Week of Feb. 20-24, 2012 Helpful information can be found on pages 127-139 of lab manual. STATION 1. SURFACE PROCESSES HOW GRANITE (plutonic rock) WEATHERS TO FORM SEDIMENT & SOIL – SURFACE PROCESSES Sediment can be made from solid rock by either chemical (e.g., equation above) or mechanical processes. Examine the 3 boxes of granite on display. 1. Describe what you see in each of the boxes, noting the changes in material. Fresh granite Weathered granite Very weathered granite 2. Name two of the minerals in the granite (minerals that you learned in Mineral Lab). 3. How is the “soil box” different from the very weathered granite box? 2KAlSi 3 O 8 + 2(H + + HCO 3 - ) + H 2 O Potassium feldspar carbonic acid water Al 2 Si 2 O 5 (OH) 4 + 2K+ + 2HCO 3 - + 4SiO 2 Clay mineral potassium bicarbonate silica ion ion Chemical weathering of potassium feldspar (the pink/orange mineral) 1 of 8
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
STATION 2. TYPES OF SEDIMENTARY ROCKS Examine the following rocks. Use Figures and posters as hints. TEXTURE Grain size, Grain Roundness, and Grain Arrangement (see Fig. 6.1) CLASSIFICATION: Detrital (siliciclastic) or Biochemical (bioclastic) or Chemical Rock name Environment (see Fig. 6.2) (There can be more than one answer for some rock samples) Rock sample #1 Rock sample #2 (see Fig. 6.6B) coquina Shallow marine (“shell gravel”) Rock sample #3 Rock sample #4 Rock sample #5 2 of 8
Background image of page 2
STATION 3. SEDIMENTARY STRUCTURES Sedimentary structures are important clues to depositional environments, providing glimpses of processes that once occurred. Many of the structures form as sediments are being deposited, for example, stratification (layering). * raindrops FRAGILE What does this sedimentary structure tell us about the ancient environment? * Ripple marks (two samples) Make a sketch of the two samples in the box below. Compare your sketch to the diagrams in Fig. 6.10. Label each sketch with the type of ripple marks, and direction of flow (if you can determine). 3 of 8
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
* graded bedding Make a sketch in the box below. Which size sediment is on bottom, which on top – what does this indicate about the environment that deposited the rock? * trace fossils
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 8

105Lab06SedRks - GEOL 105 Lab 6 Sedimentary Rocks _ Week of...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online