Topic: Rock Cycle
Rock Cycle
The cross section below represents four different rock units. The symbol for contact metamorphism has been omitted from the cross section.
The sequence below represents the relative ages of the rock units from oldest to youngest.
limestone → granite → shale → sandstone
Which cross section below represents where the symbol for contact metamorphism would be located, based on the relative age sequence?
(1)
(2)
(3)
(4)
The inclusions shown near the bottom of the Palisades sill are pieces of the Triassic sandstone that
(1) formed from deposits of minerals within the sill
(2) crystallized within the sill and were cemented together
(3) were part of the olivine-rich layer that broke apart
(4) broke off from the surrounding bedrock during the intrusion
What is the color and type of rock that forms oceanic crust at mid-ocean ridges?
(1) light colored and igneous
(2) light colored and sedimentary
(3) dark colored and igneous
(4) dark colored and sedimentary
The cross section below indicates the geologic ages of the bedrock beneath the state of Michigan. These rocks formed from sediments deposited in an ancient depositional basin. This region is called the Michigan Basin. Glacial deposits cover most of the surface.
Which process most likely caused the formation of the Michigan Basin?
(1) uplift
(2) faulting
(3) metamorphism
(4) downwarping
On the cross section in the image provided, draw the contact metamorphism symbol to indicate alllocations where contact metamorphism has occurred. [1]
Allow 1 credit for the contact metamorphism symbol drawn on only the two sides of F, as shown below.
• Example of a 3-credit response for questions 56, 57, and 58:
•
Describe one piece of evidence in the cross section indicating that the igneous rock at location C is extrusive. [1]
Allow 1 credit. Acceptable responses include, but are not limited to:
• — Rock units above letter C have not been metamorphosed.
• — Contact metamorphism is missing above location C.
• — Conglomerate and sandstone do not show contact metamorphism above letter C.
List two processes that produced unconformity XX⬘. [1]
Process 1: Process 2:
Allow 1 credit for two correct responses. Acceptable responses include, but are not limited to:
• — uplift/emergence
• — weathering
• — erosion
• — subsidence/submergence
• — deposition
• — burial
Describe one piece of evidence shown in the cross section that indicates that the Inwood marble was formed by regional metamorphism. [1]
Allow 1 credit. Acceptable responses include, but are not limited to:
• — The marble shows deformation.
• — The rock formation is folded.
• — The marble is located between two other regional metamorphic rocks.
The area between North America and South America is a tectonically active region of Earth. This region contains all of the types of tectonic plate boundaries, and it has frequent earthquake and volcanic activity. The tectonic plates on either side of the East Pacific Ridge move at an average rate of 7.5 cm/year.
Identify the type of mafic igneous bedrock that is most likely to make up the oceanic crust at location A, and state the average density of this oceanic crust. [1]
Type of bedrock: Density: g/cm3
Allow 1 credit for basalt/basaltic bedrock and a density of 3.0 g/cm3 or 3 g/cm3.