VANISHED Who Pulled The Plug On The Mediterranean? And Could It Happen Again? - IELTS Reading Answers & Explanations
From Oxford IELTS Practice Tests Academic Reading Test 1 · Part 2 · Questions 15–27
Reading Passage
You should spend about 20 minutes on Questions 15–27, which are based on Reading Passage 2.
VANISHED Who pulled the plug on the Mediterranean? And could it happen again?
Cannes. Monte Carlo. St Tropez. Magic names all. And much of the enchantment comes from the deep blue water that laps their shores. But what if somebody pulled the plug? Suppose the Mediterranean Sea were to vanish, leaving behind an expanse of salt desert the size of India. Hard to imagine? It happened.
'It would have looked like Death Valley,' says Bill Ryan, from the Lamont-Doherty Earth Observatory in New York, one of the leaders of the team that discovered the Mediterranean had once dried up, then refilled in a deluge of Biblical proportions. Between five and six million years ago, the great desiccation touched off what scientists call the Messinian Salinity Crisis – a global chemical imbalance that triggered a wrenching series of extinctions and plunged the Earth into an ice age.
The first indications of some extraordinary past events came in the 1960s, when geologists discovered that major rivers flowing into the Mediterranean had eroded deep canyons in the rock at the bottom of the sea. River erosion of bedrock cannot occur below sea level, yet somehow the River Rhone in the South of France had managed to create a channel 1000 metres deep in the sea floor, while the Nile had cut nearly 1500 metres into the rock off the North African coast. There was more: despite the fact that the formation of caves can only take place above water, scientists discovered a whole network beneath the island of Malta that reached an astonishing depth of 2000 metres below sea level.
Further evidence came to light in 1970, when an international team chugged across the Mediterranean in a drilling ship to study the sea floor near the Spanish island of Majorca. Strange things started turning up in core samples: layers of microscopic plants and soil sandwiched between beds of salt more than two kilometres below today's sea level. The plants had grown in sunlight. Also discovered inside the rock were fossilized shallow-water shellfish, together with salt and silt: particles of sand and mud that had once been carried by river water. Could the sea floor once have been near a shoreline?
That question led Ryan and his fellow team leader, Kenneth Hsü, to piece together a staggering chain of events. About 5.8 million years ago, they concluded, the Mediterranean was gradually cut off from the Atlantic Ocean when continental drift pinned Morocco against Spain. As the opening became both narrower and shallower, the deep outward flow from sea to ocean was progressively cut off, leaving only the shallow inward flow of ocean water into the Mediterranean. As this water evaporated, the sea became more saline and creatures that couldn't handle the rising salt content perished. 'The sea's interior was dead as a door nail, except for bacteria,' says Ryan. When the shallow opening at Gibraltar finally closed completely, the Mediterranean, with only rivers to feed it, dried up and died.
Meanwhile, the evaporated water was falling back to Earth as rain. When the fresh water reached the oceans, it made them less saline. With less salt in it to act as an antifreeze, parts of the ocean that would not normally freeze began to turn to ice. 'The ice reflects sunlight into space,' says Ryan. 'The planet cools. You drive yourself into an ice age.'
Eventually, a small breach in the Gibraltar dam sent the process into reverse. Ocean water cut a tiny channel to the Mediterranean. As the gap enlarged, the water flowed faster and faster, until the torrent ripped through the emerging Straits of Gibraltar at more than 100 knots. 'The Gibraltar Falls were 100 times bigger than Victoria Falls and a thousand times grander than Niagara,' Hsü wrote in his book The Mediterranean was a Desert (Princeton University Press, 1983).
In the end the rising waters of the vast inland sea drowned the falls and warm water began to escape to the Atlantic, reheating the oceans and the planet. The salinity crisis ended about 5.4 million years ago. It had lasted roughly 400,000 years.
Subsequent drilling expeditions have added a few wrinkles to Ryan and Hsü's scenario. For example, researchers have found salt deposits more than two kilometres thick – so thick, some believe, that the Mediterranean must have dried up and refilled many times. But those are just geological details. For tourists the crucial question is, could it happen again? Should Malaga start stockpiling dynamite?
Not yet, says Ryan. If continental drift does reseal the Mediterranean, it won't be for several million years. 'Some future creatures may face the issue of how to respond to nature's closure. It's not something our species has to worry about.'
Questions
Questions 15–19 Summary Completion
Complete the summary below.
Choose NO MORE THAN THREE WORDS from the passage for each answer.
The 1960s discovery of 15 in the bedrock of the Mediterranean, as well as deep caves beneath Malta, suggested something strange had happened in the region, as these features must have been formed 16 sea level. Subsequent examination of the 17 off Majorca provided more proof. Rock samples from 2000 metres down contained both vegetation and 18 that could not have lived in deep water, as well as 19 originally transported by river.
Questions 20–22 Matching Sentence Endings
Complete each of the following statements with the best ending from the box below.
Write the appropriate letters A–G.
A. Africa and Europe crashed into each other.
B. water started flowing from the Mediterranean.
C. the sea was cut off from the ocean.
D. all the fish and plant life in the Mediterranean died.
E. the Earth started to become colder.
F. the channel grew bigger, creating the waterfalls.
G. all the ice on earth melted.
Questions 23–27 One Choice
Choose the appropriate letters A, B, C or D.
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q15 | deep canyons / canyons | The first indications of some extraordinary past events came in the 1960s, when geologists discovered that major rivers flowing into the Mediterranean had eroded deep canyons in the rock at the bottom of the sea | Excerpt/Passage Explanation: The passage states that in the 1960s, scientists learned that big rivers had carved deep valleys (canyons) into the rock under the Mediterranean Sea. Answer Explanation: The answer refers to very deep valleys with steep sides that were cut into the hard rock under the sea. Reason For Correctness: The correct answer is confirmed by the third paragraph, which discusses findings from the 1960s. The text mentions that geologists found evidence of past events when they saw that rivers had "eroded deep canyons in the rock at the bottom of the sea". Therefore, "(deep) canyons" correctly fills the blank describing what was discovered in the bedrock. |
| Q16 | above | River erosion of bedrock cannot occur below sea level, yet somehow the River Rhone in the South of France had managed to create a channel 1000 metres deep in the sea floor, while the Nile had cut nearly 1500 metres into the rock off the North African coast. There was more: despite the fact that the formation of caves can only take place above water, scientists discovered a whole network beneath the island of Malta that reached an astonishing depth of 2000 metres below sea level | Excerpt/Passage Explanation: The passage explains that rivers cannot cut into bedrock when they are under the sea, and caves can only form above the water. Therefore, finding these features deep under the sea showed that the area was once above water level. Answer Explanation: The answer "above" means at a higher level than the surface of the sea or water. Reason For Correctness: The correct answer is supported by the text explaining that both river erosion and cave formation only happen over or above the water line, not below sea level. Specifically, the text states that river erosion "cannot occur below sea level" and cave formation "can only take place above water", which matches the summary phrase stating that these geological features must have formed "above" sea level. |
| Q17 | sea floor | Further evidence came to light in 1970, when an international team chugged across the Mediterranean in a drilling ship to study the sea floor near the Spanish island of Majorca | Excerpt/Passage Explanation: The passage explains that in 1970, a group of scientists traveled in a special ship to inspect and examine the bottom of the sea near Majorca to gather more proof. Answer Explanation: The answer "sea floor" refers to the solid ground at the very bottom of the sea or ocean. Reason For Correctness: The correct answer is supported by the text explaining that after the 1960s discoveries, scientists found more evidence in 1970. They used a drilling ship to examine and study the bottom of the sea ("sea floor") close to the island of Majorca. In the summary, "Subsequent examination of the" matches "study the", and "off Majorca" matches "near the Spanish island of Majorca". |
| Q18 | shallow-water shellfish / shellfish | Also discovered inside the rock were fossilized shallow-water shellfish, together with salt and silt: particles of sand and mud that had once been carried by river water | Excerpt/Passage Explanation: The passage explains that researchers found the remains of shellfish that live in shallow water inside the rock deep beneath the sea floor. Answer Explanation: The answer "shellfish" refers to small sea animals with shells (like clams or mussels) that live in water that is not very deep. Reason For Correctness: The correct answer is supported by the text, which discusses the contents found inside rock samples from deep beneath the sea. The summary mentions that these samples contained "vegetation" (microscopic plants) as well as another creature that could not survive in deep water. The passage explicitly states that scientists found "fossilized shallow-water shellfish" inside the rock, showing they were shallow-water creatures rather than deep-sea animals. |
| Q19 | salt and silt / silt / sand and mud | Also discovered inside the rock were fossilized shallow-water shellfish, together with salt and silt: particles of sand and mud that had once been carried by river water | Excerpt/Passage Explanation: The passage explains that scientists found old shellfish, salt, and silt inside the rock, and notes that this silt consists of tiny bits of sand and mud that were brought there by rivers. Answer Explanation: The answer refers to very fine earth material (silt, or tiny pieces of sand and mud) that was moved from one place to another by river currents. Reason For Correctness: The correct answer is supported by the text describing what scientists found inside the rock samples. The passage explains that along with fossils, researchers discovered "silt", which it defines as "particles of sand and mud that had once been carried by river water". Therefore, either "silt" or "sand and mud" correctly completes the phrase about material "originally transported by river". |
| Q20 | E | 'The ice reflects sunlight into space,' says Ryan. 'The planet cools. You drive yourself into an ice age.' | Excerpt/Passage Explanation: The passage explains that the ice sends sunlight back out into space, which causes the Earth to become colder and brings on an ice age. Answer Explanation: The answer means that the whole planet Earth became much colder and entered an ice age. Reason For Correctness: The correct answer is E because the passage explains that when new ice formed on the oceans, it bounced the sun's light back into space instead of absorbing its warmth. As a result, the planet became colder and entered an ice age. Keywords like 'reflects sunlight' match 'did not absorb the heat from the sun', and 'The planet cools' matches 'the Earth started to become colder'. |
| Q21 | F | As the gap enlarged, the water flowed faster and faster, until the torrent ripped through the emerging Straits of Gibraltar at more than 100 knots. 'The Gibraltar Falls were 100 times bigger than Victoria Falls and a thousand times grander than Niagara,' Hsü wrote in his book The Mediterranean was a Desert (Princeton University Press, 1983) | Excerpt/Passage Explanation: The passage explains that when the gap became larger, water rushed in faster and faster, creating giant waterfalls that were far bigger than famous waterfalls like Victoria Falls or Niagara Falls. Answer Explanation: The answer means that the water moved much faster when the opening grew wider and created huge waterfalls. Reason For Correctness: The correct answer is F because the text explains that as the opening ("the gap enlarged", matching "the channel grew bigger"), the water "flowed faster and faster" ("speed... increased"), which formed massive cascades known as the Gibraltar Falls ("creating the waterfalls"). |
| Q22 | B | In the end the rising waters of the vast inland sea drowned the falls and warm water began to escape to the Atlantic, reheating the oceans and the planet | Excerpt/Passage Explanation: The passage explains that when warm water flowed out from the Mediterranean Sea into the Atlantic Ocean, it warmed up the oceans and the Earth. Answer Explanation: The answer means that the Earth and oceans got warmer when water began flowing out of the Mediterranean Sea into the Atlantic Ocean. Reason For Correctness: The correct answer is B because the passage explains that after the Mediterranean refilled, warm water started to flow out ("escape") into the Atlantic Ocean, which reheated the oceans and the entire planet. Key phrases include "warm water began to escape to the Atlantic" (water started flowing from the Mediterranean) and "reheating the oceans and the planet" (The Earth and its oceans became warmer). |
| Q23 | D | About 5.8 million years ago, they concluded, the Mediterranean was gradually cut off from the Atlantic Ocean when continental drift pinned Morocco against Spain. As the opening became both narrower and shallower, the deep outward flow from sea to ocean was progressively cut off, leaving only the shallow inward flow of ocean water into the Mediterranean | Excerpt/Passage Explanation: The passage explains that around 5.8 million years ago, Morocco moved closer to Spain and made the opening between them smaller. Because of this, water could no longer flow out from the Mediterranean Sea into the Atlantic Ocean, and only a little ocean water could flow in. Answer Explanation: The answer means that water stopped moving out of the Mediterranean Sea into the Atlantic Ocean. Reason For Correctness: The correct answer is D because the text explains what happened around 5.8 million years ago when the land moved. As the opening between the land narrowed and became shallower, the deep movement of water from the Mediterranean Sea out into the Atlantic Ocean was blocked (progressively cut off). |
| Q24 | A | As this water evaporated, the sea became more saline and creatures that couldn't handle the rising salt content perished | Excerpt/Passage Explanation: The passage explains that when the water evaporated, the sea got saltier, and the sea animals and plants that could not survive the high salt levels died. Answer Explanation: The answer means that living things died because the sea water contained too much salt. Reason For Correctness: The correct answer is A because the text clearly states that as the water dried up (evaporated), the Mediterranean Sea became more saline (saltier). Living creatures could not survive the high amount of salt and died (perished). |
| Q25 | B | 'The planet cools. You drive yourself into an ice age.' Eventually, a small breach in the Gibraltar dam sent the process into reverse warm water began to escape to the Atlantic, reheating the oceans and the planet |
Excerpt/Passage Explanation: The passage explains that the cooling of the planet led Earth into an ice age, but when the blockage at Gibraltar broke open, the whole cooling process was reversed, warming the Earth back up. Answer Explanation: The answer states that what happened at Gibraltar caused an ice age to start and then later come to an end. Reason For Correctness: The correct answer is B because the passage explains two major events at Gibraltar. First, when the opening at Gibraltar closed completely, water evaporation caused changes in ocean salt levels and freezing, which pushed the Earth into an ice age ('You drive yourself into an ice age'). Later, a break or opening in the Gibraltar dam reversed this entire process, allowing warm water to flow back out and warm up the planet again ('reheating the oceans and the planet'). Thus, the events at Gibraltar caused both the start and the conclusion of an ice age. |
| Q26 | C | Subsequent drilling expeditions have added a few wrinkles to Ryan and Hsü's scenario. For example, researchers have found salt deposits more than two kilometres thick – so thick, some believe, that the Mediterranean must have dried up and refilled many times | Excerpt/Passage Explanation: The passage explains that later scientific investigations found salt layers thicker than two kilometres. Because of this, some scientists think the Mediterranean Sea dried out and filled back up with water over and over again. Answer Explanation: The answer means that newer research suggests the Mediterranean Sea might have been separated from the ocean multiple times, not just one time. Reason For Correctness: The correct answer is C because the passage mentions that newer drilling trips discovered massive layers of salt. These thick salt layers lead some scientists to believe that the sea dried up and filled with water again multiple times ("dried up and refilled many times"). This matches the idea in option C that it may have been cut off more than once. In the text, "Subsequent drilling expeditions" means "More recent studies," and "dried up and refilled many times" matches "cut off more than once." |
| Q27 | D | If continental drift does reseal the Mediterranean, it won't be for several million years. 'Some future creatures may face the issue of how to respond to nature's closure. It's not something our species has to worry about.' | Excerpt/Passage Explanation: The passage explains that if the sea closes up again, it will take millions of years, so humans will not have to experience or worry about this event. Answer Explanation: The answer means that human beings will not be around or live long enough to witness the Mediterranean Sea drying up. Reason For Correctness: The correct answer is D because at the end of the article, Ryan explains that if the Mediterranean ever closes and dries up again, it will not happen for several million years. He states that only "future creatures" might deal with it, meaning "our species" (human beings) does not need to worry about it happening during our existence. |