Topic: Geologic History
Geologic History
The map below shows the location of the Chicxulub impact crater, which was formed in the Gulf of Mexico approximately 65.5 million years ago. With an estimated 108-mile diameter, this crater, which is now buried beneath surface crustal rocks, is one of the largest craters on Earth.
The asteroid impact that formed this large crater is theorized to have caused
(1) a drop in sea level from the sea water draining into the large crater
(2) warmer than normal worldwide ocean temperatures from the hot asteroid
(3) mass extinctions of many species on Earth from extreme climate changes
(4) an increase in worldwide greenhouse gases from vaporizing crustal rocks
One group of organisms that existed on Earth before 550 million years ago was
(1) sharks
(2) insects
(3) Ediacaran fauna
(4) Burgess shale fauna
Which event occurred approximately 4.6 billion years ago?
(1) evolution of the earliest fish
(2) evolution of stromatolites
(3) formation of the oldest known Earth rocks
(4) formation of Earth and our solar system
Approximately how many million years ago (mya) were all of Africa and South America inferred to be located south of the equator?
(1) 59 mya
(2) 119 mya
(3) 232 mya
(4) 359 mya
Ice Ages
Earth has undergone many ice ages, each lasting millions of years. Some scientists infer that most ice ages were caused by landmasses blocking the ocean currents between equatorial regions and the poles. Ice ages usually ended when the positions of continents allowed ocean currents to resume transporting equatorial heat to the poles.
During each ice age there were advances and retreats of glaciers. These cool glacial and warm interglacial climate intervals were caused mostly by changes in Earth’s orbit and tilt. Earth is presently in a warm interglacial interval.
Approximately 359 million years ago, the average intensity of insolation received in a year by the land area that is now eastern North America was likely
(1) greater, because eastern North America was at a lower latitude
(2) greater, because eastern North America was at a higher latitude
(3) less, because eastern North America was at a lower latitude
(4) less, because eastern North America was at a higher latitude
Approximately how many million years ago (mya) was the Coconino sandstone deposited as sediment?
(1) 180 mya
(2) 275 mya
(3) 330 mya
(4) 495 mya
The map below shows the location of the Chicxulub crater, which was formed when a massive asteroid impacted Earth 65.5 million years ago.
Scientists infer that this impact contributed to the extinction of
(1) trilobites
(2) gastropods
(3) many land plants
(4) placoderm fish
Labeled lines on the map below show the inferred location of Earth’s equator during the middle of several geologic periods.
Approximately how many million years ago (mya) was the region around current-day Watertown, New York, located the nearest to the equator?
(1) 270 mya
(2) 300 mya
(3) 340 mya
(4) 450 mya
Early in its formation, Earth was a molten mass of evenly mixed composition. During the next few million years, the heavier and more dense elements sank to the center, while lighter and less dense elements rose toward the surface. This is called chemical fractionation.
Approximately how many years ago did Earth and other planets in our solar system begin the process of chemical fractionation?
(1) 8.2 billion years ago
(2) 13.8 billion years ago
(3) 542 million years ago
(4) 4600 million years ago
The formation of the planet Uranus is estimated to have occurred approximately
(1) 100,000 million years ago
(2) 2.0 billion years ago
(3) 4.6 billion years ago
(4) 13.7 billion years ago
The Niagara Escarpment
A prominent feature found along the shore of Lake Ontario in western New York State is the Niagara Escarpment. This escarpment is the remains of an ancient seabed that was formed when the area was covered by a warm, shallow sea from approximately450 to 430 million years ago. Erosion of the Taconic Mountains to the east provided
the sediments deposited in this basin area. From these sediments, rock layers such as shale, sandstone, and limestone formed. Later, magnesium replaced some of the calcium in the top layer of limestone, turning it into a dolostone layer. When the high ocean levels of the Ordovician Period dropped, the draining of this inland sea caused unequal erosion of the exposed layers. The South Moraine was deposited on the top of the Niagara Escarpment in this region.
Describe the tectonic event that caused the Taconian orogeny. [1]
Allow 1 credit. Acceptable responses include, but are not limited to:
• — the collision between North America and a volcanic island arc
• — closing of the western part of the Iapetus Ocean
• — crustal uplift
• — convergence
How many million years ago did Earth and the solar system form? [1]
million years ago
Allow 1 credit for a value equivalent to 4600 million years ago.
• Note: If the student crosses out million years ago, allow credit if an equivalent value is expressed
• in other units (e.g. 4.6 billion years ago).
State the approximate age of the Redwall limestone, in million years. [1]
my
Allow 1 credit for any value from 318 my to 359 my.
State the number of million years ago (mya) for the estimated time of origin of our solar system. [1]
Allow 1 credit for 4600 mya.
• Note: Allow credit if an equivalent value is expressed in other units (e.g., 4.6 billion years ago), if
• the student crosses out mya (million years ago).
Meteorite Composition
Meteors that strike Earth’s surface are called meteorites. Analysis of meteorite composition has provided scientists with information regarding the formation of Earth and our solar system, and possibly the development and evolution of life on Earth.
Two types of meteorites are iron meteorites and chondrites. Iron meteorites consist mostly of iron and nickel, and are inferred to be from core materials of early planetary bodies in our solar system. More than 60% of meteorites studied have been identified as chondrites. Chondrites are made of millimeter-sized spheres of olivine and pyroxene crystals embedded in a mass of mineral and metal grains. The chondrites are thought to represent fragments of the earliest solid materials in our solar system. One type of chondrite, the carbonaceous chondrite, contains water, organic compounds, and minerals that represent the chemical composition necessary for life to form.
What is the estimated age, in years, of Earth and our solar system? [1]
y
Allow 1 credit. Acceptable responses include, but are not limited to:
• — 4,600 million y
• — 4.6 billion y
• — 4,600,000,000 y