LAB 4: SEDIMENTARY RoCKS Extension 1. How old are the oldest reported sedimentar

ID: 153535 • Letter: L

Question

LAB 4: SEDIMENTARY RoCKS Extension 1. How old are the oldest reported sedimentary rocks? 2. What is the difference between sediment and sedimentary rocks? Hint: Define both. 3. Explain uniformitarianism: 4. There are two primary types of sedimentary rocks. Complete the table below with information about these two types: Type How does it form? How is it classified? 5. You find two deposits of sediment out on your hike. Deposit A consists of well-rounded sand, containing mostly pure quartz Deposit B contains angular, gravel-sized rock particles. What can you tell about the erosional history of the two different sediment deposits? Explain/support your answer in terms of rounding and sorting.

Explanation / Answer

1. Earth, S oldest sedimentary rock found in Greenland are about 3.9 billion years old.

2. Sediment is the weather material from an existing rock either a previous sedimentary one or igneous or metamorphic.

A sedimentary rock is when these sediments are compacted and undergo lithification.

3. Uniformitarianism is an important concept in geology that addresses the consistent behavior of geological processes over time. The concept is that the natural processes behave more or less in the same way today as they have throughout the past and will continue to do so in the future. Geologists sometimes summarize the concept in the phrase that 'present is the key to the past '.4.

These are classified according to the grain size of the particles.

Boulder(>256mm)

Cobble(64-256mm)

Pebble(2-56mm)

Sand(1/16-2mm)

Silt(1/256-1/16mm)

Clay(<1/256mm)

non classic rocks are named according to the mineral present.

Limestone : composed of calcite

Rock salt: composed of halite

Chert: composed of microscopic quartz grains

Types How does it form? How is it classifiesd? Classic rock originated from the breakdown of other rocks (could be sedimentary, metamorphic or igneous) due to the process of weathering and erosion.