Question

Melanie Sherman
The Big Muddy
The grand old Mississippi River has been changing since it formed some 20 million years ago. As one of the United States' largest rivers, as many as two-thirds of states drain partially or entirely into the Big Muddy. As water travels across the land on its way to the mighty Mississippi River, large amounts of soil, dirt, and rock are broken off, picked up, and relocated along the way. All of this weathered and eroded soil and dirt gives the water in the Mississippi a brown color as it moves towards the Gulf of Mexico. Once the dirt and soil reach the Gulf of Mexico, it is deposited at the river’s mouth, forming the wetland area of the Mississippi River Delta. This delta is home to some of the most fertile land in the United States. Each year, the Mississippi River needs to be dredged. Dredging is the act of removing dirt from the river’s bed to increase or maintain the depth of the river. Once the sediments have been removed, they are relocated using a large pipeline


Part A
Using sources, by which number in The Rock Cycle is the dirt and soil being dredged out of the Mississippi River each year MOST LIKELY represented?
Responses
A 1: Igneous rock1: Igneous rock
B 2: Sediments2: Sediments
C 4: Metamorphic rock4: Metamorphic rock
D 5: Magma5: Magma
Question 2
Part B
Which piece of evidence BEST explains your reasoning behind your answer in Part A?
Responses
A The soil is the result of the weathering, erosion, and deposition of rockThe soil is the result of the weathering, erosion, and deposition of rock
B The soil is the result of crystallizationThe soil is the result of crystallization
C The soil is the result of heat and pressureThe soil is the result of heat and pressure
D The soil is the result of compacting, cementing, and lithification

Answer 1

Part A: B — 2: Sediments

Part B: A — The soil is the result of the weathering, erosion, and deposition of rock.

Explanation: The dredged material is unconsolidated particles (sand, silt, clay) created by weathering and erosion and then transported and deposited by the river, which are classed as sediments in the rock cycle.