The Billion Year Quiz

It may be hard to imagine while standing in Times Square, but the real estate taken up by New York City has been something other than a cityscape for more than 99.99 percent of its history. This piece of continental crust has been a mountain range (more than once!), the ocean floor, glacier-covered bedrock and the residence of countless creatures largely lost in time. But the rocks have preserved plenty of clues about these lost worlds. See if you're up to cracking some of the fascinating chapters of this billion-year-old-story.

True or False: Dinosaur fossils, especially tracks and footprints, are relatively common in New York state.

True

False

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Because the rocks dating back to the time of the dinosaurs have been almost completely eroded away across the entire state, there is almost no direct evidence of dinosaurs. However, finds of several species of early dinosaurs across the Hudson River in New Jersey suggest that New York was likely home to the same species. Later, during the age of the dinosaurs, dry land gave way to rising ocean waters and parts of southeastern New York may have been home to the same large marine reptiles known to inhabit the seaways of the North American interior.

The bedrock formations that lie beneath New York City show clear evidence of having been severely deformed multiple times. How many times has the crust along this portion of eastern North America collided with other tectonic plates to create uplift and mountain building?

one

two

three

four

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New York along with the entire New England region have experienced a violent geologic history. Collisions with plates lying to the east and south have slammed into the continental margin at least four times beginning about a billion years ago and finally subsiding around 300 million years ago. Thus for most of its history, the New York area has been dominated by elevated, rugged terrain often associated with intense periods of volcanic activity and earthquakes.

True of False: Extinct marine predators known commonly as sea scorpions are the largest arthropods (the group that includes all insects, spiders, crabs, etc.) that have ever inhabited New York.

True

False

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Sea scorpions, or eurypterids, were one of the most common residents of the shallow seas, lagoons and estuaries that covered much of New York from about 425 to 300 million years ago. The largest of the eurypterid species in this region probably measured several feet in length, making them considerably more formidable than the monster cockroaches that terrorize New York City today.

The New York City area was once covered by glaciers. What was the approximate maximum thickness of the ice sheet?

300 feet

1,500 feet

3,000 feet

over a mile

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During the last major phase of glaciation, between 75,000 to 17,000 years ago, the ice sheet covering about 90 percent of New York state is estimated to have reached a thickness of more than mile.

Around 15,000 years ago, near the end of the last Ice Age, Manhattan Island was overrun with a different type of rodent known as the giant beaver. In contrast to the tens of millions of brown rats that live in present-day New York City -- and fortunately on average weigh no more than a pound -- the giant beaver weighed as much as:

50 pounds

200 pounds

500 pounds

1000 pounds

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The giant beaver, known scientifically as Castroides, was a monster among rodents, reaching the size of a medium-size bear. It carried a pair of 6-inch-long incisors, but the shape of these formidable teeth suggests the prehistoric animals didn't use them for felling trees, like modern beavers do. These massive rodents thrived in the marshy terrain bordering lakes across Manhattan Island and beyond, probably eating a strictly vegetarian diet of softer pond plants.

Which of these features of the greater New York area are the result of glacial action?

Long Island

boulders in Central Park

Brooklyn's Prospect Park

all of the above

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Long Island is a glacial feature known as a terminal moraine. It formed when millions of tons of scoured debris were dropped as the glaciers began their retreat during the end of the last ice age. The boulders in Central Park were carried south from present-day Canada or New England and then dropped when the glaciers melted. Prospect Park is the last remnant of the bog-filled terrain carved by glacial action.

New York City now sits at about 40 degrees of latitude north of the equator. But over the last 500 million years, what is the closest that this piece of Earth's crust ever got to the equator?

20 degrees north latitude

12 degrees north latitude

5 degrees north latitude

0 degrees (on the equator)

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During at least two tectonic shifts, the New York City area passed over the equator. In fact, from at least 540 million years ago up until about 300 million years ago, the crust under New York City lay consistently south of the equator. For most of the known geologic record, it lay closer to the equator than it is today.

The famous Hudson Palisades are made up of a largely igneous formation formed about 200 million years ago when:

lava poured out of great fissures in the crust that opened up when the North American continent began to separate from Africa

the collision of North America and Europe created an extensive volcanic belt along the boundary of the two plates.

a huge asteroid struck the area, melting the bedrock and creating sudden massive lava flows.

a glacier carved out a corridor along the softer bedrock that lines the Hudson River Valley.

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Nearly 200 million years ago, the distinctive pillar-like rocks of the Palisades were formed when the North American and African plates pulled apart to initiate the opening of the Atlantic Ocean. This rifting event opened up fissures in sandstone beds along the margin of North America, which were then filled by molten magma rising from below, giving the formation its columnar "palisade" structure.

Too bad

Spend a little more time at the natural history museum.

Tough Questions

You nailed a few, but brush up on more "deep time."

Outstanding!

Treat yourself at the Dinosaur BBQ.