OG Test 4 - Reading 5

Questions 42-52 are based on the following passage.

This passage is adapted from Carolyn Gramling, “Source of Mysterious Medieval Eruption Identified.”© 2013 by American Association for the Advancement of Science.
About 750 years ago,a powerful volcano erupted
somewhere on Earth,kicking off a centuries-long
cold snap known as the Little Ice Age.Identifying the
Linevolcano responsible has been tricky.
5That a powerful volcano erupted somewhere in
the world,sometime in the Middle Ages,is written in
polar ice cores in the form of layers of sulfate
deposits and tiny shards of volcanic glass. These
cores suggest that the amount of sulfur the mystery
10volcano sent into the stratosphere put it firmly
among the ranks of the strongest climate-perturbing
eruptions of the current geological epoch,the
Holocene, a period that stretches from 10,000 years
ago to the present. A haze of stratospheric sulfur
15cools the climate by reflecting solar energy back into
In 2012, a team of scientists led by geochemist
Gifford Miller strengthened the link between the
mystery eruption and the onset of the Little Ice Age
20by using radiocarbon dating of dead plant material
from beneath the ice caps on Baffin Island and
Iceland, as well as ice and sediment core data,to
determine that the cold summers and ice growth
began abruptly between 1275 and 1300C.E.(and
25became intensified between 1430 and 1455C.E.).
Such a sudden onset pointed to a huge volcanic
eruption injecting sulfur into the stratosphere and
starting the cooling. Subsequent,u nusually large and
frequent eruptions of other volcanoes, as well as
30sea-ice/ocean feedbacks persisting long after the
aerosols have been removed from the atmosphere,
may have prolonged the cooling through the 1700s.
Volcanologist Franck Lavigne and colleagues now
think they`ve identified the volcano in question:
35Indonesia`s Samalas.One line of evidence,they note,
is historical records. According to Babad Lombok,
records of the island written on palm leaves in Old
Javanese, Samalas erupted catastrophically before the
end of the 13th century, devastating surrounding
40villages-including Lombok`s capital at the time,
Pamatan-with ash and fast-moving sweeps of hot
rock and gas called pyroclastic flows.
The researchers then began to reconstruct the
formation of the large,800-meter-deep caldera[a
45basin-shaped volcanic crater] that now sits atop the
volcano.They examined 130 outcrops on the flanks
of the volcano, exposing sequences of pumice-ash
hardened into rock-and other pyroclastic material.
The volume of ash deposited, and the estimated
50height of the eruption plume (43 kilometers above
sea level) put the eruption`s magnitude at a
minimum of 7 on the volcanic explosivity index
(which has a scale of 1 to 8)-making it one of the
largest known in the Holocene.
55The team also performed radiocarbon analyses on
carbonized tree trunks and branches buried within
the pyroclastic deposits to confirm the date of the
eruption; it could not,they concluded, have
happened before 1257C.E.,and certainly happened
60in the 13th century.
It`s not a total surprise that an Indonesian volcano
might be the source of the eruption,Miller says."An
equatorial eruption is more consistent with the
apparent climate impacts."And, he adds, with sulfate
65appearing in both polar ice caps-Arctic and
Antarctic-there is"a strong consensus"that this
also supports an equatorial source.
Another possible candidate-both in terms of
timing and geographical location-is Ecuador`s
70Quilotoa,estimated to have last erupted between
1147 and 1320C.E.But when Lavigne`s team
examined shards of volcanic glass from this volcano,
they found that they didn`t match the chemical
composition of the glass found in polar ice cores,
75whereas the Samalas glass is a much closer match.
That,they suggest,further strengthens the case that
Samalas was responsible for themedieval"year
without summer"in 1258 C.E.

Question 42

The main purpose of the passage is to

  • A describe periods in Earth`s recent geologic history.

  • B explain the methods scientists use in radiocarbon analysis.

  • C describe evidence linking the volcano Samalas to the Little Ice Age.

  • D explain how volcanic glass forms during volcanic eruptions.

Question 43

Over the course of the passage,the focus shifts from

  • A a criticism of a scientific model to a new theory.

  • B a description of a recorded event to its likely cause.

  • C the use of ice core samples to a new method of measuring sulfates.

  • D the use of radiocarbon dating to an examination of volcanic glass.

Question 44

Which choice provides the best evidence for the answer to the previous question?

  • A Lines 17-25("In 2012...1455C.E.")

  • B Lines 43-46("The researchers...atopthevolcano")

  • C Lines 46-48("They examined...material")

  • D Lines 55-60("The team...13th century")

Question 45

The author uses the phrase "is written in"(line 6 )most likely to

  • A demonstrate the concept of the hands-on nature of the work done by scientists.

  • B highlight the fact that scientists often write about their discoveries.

  • C underscore the sense of importance that scientists have regarding their work.

  • D reinforce the idea that the evidence is there and can be interpreted by scientists.

Question 46

Where does the author indicate the medieval volcanic eruption most probably was located?

  • A Near the equator,in Indonesia

  • B In the Arctic region

  • C In the Antarctic region

  • D Near the equator,in Ecuador

Question 47

Which choice provides the best evidence for the answer to the previous question?

  • A Lines 1-3("About 750...Ice Age")

  • B Lines 26-28("Such a...the cooling")

  • C Lines 49-54("The volume...the Holocene")

  • D Lines 61-64("It`s not...climate impacts")

Question 48

As used in line 68,the phrase "Another possible candidate" implies that

  • A powerful volcanic eruptions occur frequently.

  • B the effects of volcanic eruptions can last for centuries.

  • C scientists know of other volcanoes that erupted during the Middle Ages.

  • D other volcanoes have calderas that are very large.

Question 49

Which choice best supports the claim that Quilotoa was not responsible for the Little Ice Age?

  • A Lines 3-4("Identifying...tricky")

  • B Lines 26-28("Such a...cooling")

  • C Lines 43-46("The researchers...atop the volcano")

  • D Lines 71-75("But...closer match")

Question 50

According to the data in the figure,the greatest below-average temperature variation occurred around what year?

  • A 1200 CE

  • B 1375 CE

  • C 1675 CE

  • D 1750 CE

Question 51

The passage and the figure are in agreement that the onset of the Little Ice Age began

  • A around 1150 CE.

  • B just before 1300 CE.

  • C just before 1500 CE.

  • D around 1650 CE.

Question 52

What statement is best supported by the data presented in the figure?

  • A The greatest cooling during the Little Ice Age occurred hundreds of years after the temperature peaks of the Medieval Warm Period.

  • B The sharp decline in temperature supports the hypothesis of an equatorial volcanic eruption in the Middle Ages.

  • C Pyroclastic flows from volcanic eruptions continued for hundreds of years after the eruptions had ended.

  • D Radiocarbon analysis is the best tool scientists have to determine the temperature variations after volcanic eruptions.


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