Section 1

This is the first section of your IELTS Reading test. You should spend about twenty minutes on it. Read the passage and answer questions 1-15.

Ruby Land: The Gems and Geology of Myanmar's Mogok Stone Tract

1. Mogok, a historic city in northern Myanmar (Burma), lies in a valley 50 miles west of the snaking Irrawaddy River, about 3,500 feet above sea level. The shrub- and flower-covered hills rising above are dotted with small towns, villages, and garden plots, and adorned with well-tended Buddhist shrines. The spires of these gold-leaf-covered pagodas reach skyward, like gilded sculptures arising from rock-outcroppings along not just the area’s one major highway but also its dirt roads and walking paths.
2. Mogok is best known for its gemstones, including ruby, sapphire, spinel, peridot, and moonstone. For centuries, the Mogok Stone Tract’s hills were legendary for such amazing abundance that locals were said to come upon gems just glinting in the grass in their gardens. The area is still world-famous for gems: A sign along the highway reads “Welcome to Ruby Land,” as about 1,000 working mines and diggings are found there today; most of the world’s finest gem rubies come from Myanmar, most of these from Mogok.
3. “Geologically, Mogok is an unusual place,” says Curator George Harlow, who specializes in minerals and gems. Dr. Harlow has visited the country’s mineral-rich regions three times since his first trip in 1997-8—a trip that the not-prone-to-hyperbole curator described as “a jaw-dropping experience. I don’t know another place on the entire planet that has such a diverse suite of minerals.”
4. Until 2011, the country was ruled by a military junta, and travel was greatly restricted, even for researchers. Since a government transition, a series of political reforms in this Buddhist nation of about 56 million people is gradually opening its borders to scientists, businesspeople, and even more so to tourists, in some places.
5. In November 2013, a group of Museum geologists finally got a long-awaited opportunity: to travel to Mogok to study the complex geological evolution of “Ruby Land.” Why was it that the region was so rich in gem-quality minerals, which are, by definition, rare? Harlow was joined by Curator James Webster, who studies magma processes, and Senior Scientific Assistant Jamie Newman, on a Constantine S. Niarchos expedition supported by the Stavros Niarchos Foundation.
6. Unlike other mineral resources, gemstones do not generally form in large ore deposits. Instead, the deposits are usually small and found only in certain geologic environments. The Mogok Stone Tract is unique because it contains several very different environments, offering one clue as to why the region is so gem-rich.
7. These sources include igneous (formed from magma) intrusions called pegmatites that can form large gem pockets inside other rocks. Magmas reacted with preexisting rock (which researchers call country rock) to form sapphire, moonstone, and certain rare gemstones. Metamorphism by heat, pressure, and passing fluid transformed limestone to marble and created Mogok rubies and spinels, a related red gem, during mountain-building as long ago as 200 million years. Weathering of all these rocks created river and cavern concentrations of gems, historically the richest deposits of all.
8. Another explanation for the presence of certain gems in Mogok, says Dr. Webster, could be the ancient circulation of extremely hot watery fluids through Earth’s crust, which might have helped minerals dissolve and re-form in veins or at contacts between different types of rock. “It’s really about hot water,” says Webster. “At one time, it must have dissolved certain things out of the rock—changing minerals to other minerals.” One hypothesis is that a portion of the Mogok deposits of the mineral corundum—a very hard mineral, second only to diamond, known to us in its red form as ruby and in many other colors as sapphire—formed in this way about 15 to 25 million years ago.

In March 2002, when satellite images showed that 1300 square miles of Antarctica’s Larsen B ice shelf—a slab bigger than the state of Rhode Island—had fragmented into a mass of floating ice chunks, scientists began to view Earth’s polar regions in a new way.

“Suddenly the possibility that global warming might cause rapid change in the icy polar world was real,” said polar geophysicist Robin Bell, lead scientist for the Changing Ice, Changing Coastlines initiative at Columbia’s Lamont Doherty Earth Observatory. When Larsen B broke apart, the glaciers feeding the ice shelf started slipping more rapidly into the sea, adding to its volume. “For a long time people didn’t think ice shelves mattered, but when Larson B broke up and we saw the ice streams speed up, we knew they mattered.”

In response, Bell and her colleagues developed a project to monitor the world’s largest block of floating ice. For two years, the Rosetta-Ice Project has been flying over Antarctica’s Ross Ice Shelf, assembling an unprecedented view of its structure and hints of how that structure is changing over time. Rosetta will fly for the last time this fall, but the project’s scientific legacy will continue to thrive for decades to come.

Why Ice Shelves Matter

The great ice sheets blanketing Greenland and Antarctica hold enough water to raise the global sea level by more than 200 feet. For context, a third of the world’s population lives within about 300 feet of sea level, and many of the planet’s largest cities are situated near an ocean. Ice shelves—floating platforms of ice—help to hold the ice sheets safely on land.

Ice shelves, like icebergs, are mainly below the waterline. This means that the majority of the shelf is not visible to the unaided eye. Ten years ago, scientists wanted to find a way to study how the ice, ocean, and underlying land interact so they could identify potential change in the ice shelf from climate change. So Bell and a colleague developed the idea for a project that would achieve that level of understanding of the Ross Ice Shelf. At the time, the sophisticated equipment needed to track above and delve beneath and within the ice shelf had yet to be developed.

That changed with the American Recovery and Reinvestment Act of 2009. Bell’s team was awarded a multi-million grant to develop IcePod, an integrated ice imaging system that can measure in detail both the ice surface and the ice bed. The system is enclosed in a pod that is mounted on the rear door of an aircraft. The pod is equipped with instruments that collect an array of measurements and is deployed for routine and targeted missions across Antarctica and Greenland. With the ability to regularly collect concurrent data on the change in ice volume and the underlying processes, IcePod allows researchers to examine not just “how fast” the ice sheets are changing but “why.”

Seeing Through the Ice

 “The project is much like the Rosetta Stone,” said Lamont polar scientist Margie Turin. “The historic stone was inscribed in three different scripts, each telling the same story but in a different tongue. When matched together, the information was enough to allow scholars to decode an ancient language. The Rosetta Project in Antarctica also brings together three different ‘scripts,’ but in this case they are written by three Earth systems; the ice, the ocean, and the underlying bed each have a story to tell. Mapped together, these three systems can be used to unlock the mysteries of Antarctic ice history in this region and help us to develop models for predicting future changes in Antarctic ice.”

Ice shelves are vulnerable from two directions: warming air above and warming water below. Scientists have been measuring air temperatures for several years, but measuring water temperatures beneath the ice is more difficult. Bell and her colleagues in the Rosetta-Ice Project have been flying transects across the ice shelf over the past two years, using IcePod to map the floating ice shelf and the sea floor below it, looking in particular for channels where less-cold water could be getting in and melting the ice shelf from below.

Once completed, the Rosetta-Ice Project will be a critical milestone in climate science.