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Unformatted text preview: Geol 107 Lab 6 - Sediments Week of Oct. 3-7, 2011 INTRODUCTION Sediment – particles of organic or inorganic matter that accumulate in a loose, unconsolidated form. Types of sediment Sediment can be classified by particle size , or by source (such as terrigenous, biogenous, or hydrogenous). Most sediments on the ocean floor are a mixture of biogenous and terrigenous particles, with an occasional component of hydrogenous. PART A. FROM MOUNTAINS TO SHORELINE - terrigenous sediment example 1. Examine the igneous rock granite in the three trays. What happens to this rock as it is weathered? 2. Match the sample sediment (jars) to the “site” on the poster where that particular sediment might be found. Keep in mind there are gradual changes in sediment between the “sites.” Use the size chart as a guide to scale. Jar E _________ Jar W ___________ Jar P _____________ Jar K _________ Jar Q __________ see color poster 1 of 6 What happens to sediment once it reaches the ocean? Let’s do a simple experiment to find out. PART B. HOW FAST DOES SEDIMENT SETTLE THROUGH THE WATER? Settling Tube Experiment Turn the tube upside down then place it back on the table. Watch and record what happens as outlined below: 1. How long does it take for the gravel to settle? 2. How long does it take for the sand to settle? 3. How long does it take for approximately 2 cm of silt to accumulate? Wait long enough for the silt layer to be easily distinguished (at least two minutes). 4. Calculate the settling velocity for the sand layer. Use the equation rate = distance/time 5. Calculate the settling velocity for the silt layer. 6. Write a one or two - sentence hypothesis about the relationship between grain size and settling rate. Now that we have a sense of how sediment will settle and accumulate in a small tube, let’s look at accumulation in the ocean. . . . ....
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- Spring '11
- Economics, Sediment, Silt, Cook Islands, Pelagic sediments