A Lecture About A Crater In Australia - IELTS Listening Sample Answer

Sep 16, 2021

The IELTS Listening section examines a candidate’s listening skills through four sections. IELTS listening section four contains a monologue about a crater in Australia. This IELTS listening sample contains a total of ten questions and three question types:

Label the diagram
Choose the correct answer
Sort answer questions

Audio Transcript

You will hear part of a lecture about a crater in Australia. First, you have some time to read questions 31 to 40.

Now listen carefully and answer questions 31 to 40.

Like Acraman in South Australia is Armageddon for the purist. No other meteorite impact on the earth has stamped the surrounding rocks with such an abiding, unequivocal geological record of collision, earthquake, wind, fire and tsunami, the giant waves formed by major earth movements. The story it tells is elemental, without dying dinosaurs or even Bruce Willis to complicate it's simple message of destruction.

First, the numbers. About 590 million years ago, a rocky meteorite more than four kilometers across and traveling at around 90,000 kilometers an hour, slammed into an area of red volcanic rock about four hundred and thirty kilometers northwest of Adelaide. Within seconds, the meteorite vaporized in a ball of fire carving out a crater about 4 kilometers deep and 40 kilometers in diameter and spawning earthquakes fierce enough to raise 100-meter height tsunamis in a shallow sea 300 kilometers away. Ancient, stable, and unglaciated, the big rock of Australia preserves some of the most photogenic impact craters in the world. Acraman is not one of them. Half a billion years of erosion has taken its toll.

A salt pan surrounded by low hills is all that remains to mark the site of the cataclysm. The true nature of the place dawned on geologist George Williams of Adelaide University in 1979. Gazing at a sheaf of newly acquired satellite images, he saw the small circular shape of lake Acraman surrounded by a ring of faults and low scarves 40 kilometers across and an outer ring twice this size. A year later, he made it to the site. On the islands near the center of the lake Williams found bedrock shattered in a conical pattern that experts consider a sure sign of a meteorite impact except for a crater that had long since eroded. The area was a textbook example of an impact site. In 1985 further intriguing evidence turned up. Vic Ghost, another Adelaide geologist, has been studying a thin band of fragmented red volcanic rock in 600 million-year-old shale in the Flinders ranges more than 300 kilometers east of Acraman. To his bewilderment, the volcanic chunks turned out to be a billion years older than the shale.

Where did they come from? Comparing samples, Ghostin and Williams found that their rocks were identical. The Red Rock in the Flinders ranges had been blasted there from Acraman. Later the same material turned up at sites 500 kilometers from Acraman.

Everywhere, the bands or fragments showed the same structure. Course pebbles at the bottom, then a cocktail of silt and sand, then layers of increasingly fine sand distorted on top into a wavy scalloped pattern. These layers also show step by step how a meteorite transformed the floor of an ancient sea hundreds of kilometers away. According to Malcolm Wallace of Melbourne University, first came earthquakes traveling at about three kilometers a second. Shock waves arrived offshore within a minute or two of the collision, stirring up the water with clouds of silt as the sea bed shook, then shattered rock from the explosion arrived by air. Pebbles and boulders crashed into the water reaching a depth of about 200 meters within a minute. One day they would become the lower band of Flinders rock. Sand took up to an hour to come to rest finally bedding down with the silt that was also now settling on the seafloor as the effects of the earthquake died away. This mixture would eventually form the next layer. About an hour after the meteorite’s impact, huge waves rolled in, leaving the ripples on the surface that later hardened into rock. Clear as mud is not an oxymoron in Acraman, the arid timeless Australian outback has preserved the closest thing the earth can boast to a perfect pockmark. The pinnacle of imperfection.

That is the end of the listening test.

Question 31-33

Label the diagram.

Write NO MORE THAN TWO WORDS AND/OR A NUMBER for each answer

Question 31.

Answer: 90,000/ninety thousand

Explanation: The monologue mentioned the speed of the meteorite which was 90,000 kilometers an hour

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Question 32.

Answer: 4 km

Explanation: The depth of the Cater was about 4 kilometers. Within a few seconds, it vaporized in a ball of fire.

Question 33.

Answer: 40 km

Explanation: The Acraman Crater was 40 kilometers in diameter.

Question 34-36

Choose from letters A-C and write them next to 34-36 on your answer sheet.

Question 34. The crater at Acraman is

Nowadays it is entirely covered by seawater.
one of the most beautiful on Karth.
less spectacular than others in Australia.

Answer: C

Explanation: Australia preserves some of the best photogenic impact craters in the world but unfortunately Acraman is not one of them.

Question 35. Williams realized what had happened at Acraman when he

saw pictures of the area taken from above.
visited Acraman for the first time in 1980.
noticed a picture of the crater in a textbook.

Answer: A

Explanation: The geologist George William when saw the satellite pictures of Acraman he found that small circular shape of lake Acraman surrounded by a ring of faults

Question 36. Where was the rock from Acraman found?

Only in the Flinders mountains.
At several places over 300 km from Acraman.
At a place 500 km from Acraman, but nowhere else.

Answer: B

Explanation: the monologue mentions that the rock from Acraman was found at various places in the Flinders ranges more than 300 kilometers east of Acraman

Question 37-40

Write NO MORE THAN THREE WORDS for each answer.