CLIL - PRE - 01 Zeměpis na II.stupni – CLIL výuka Číslo operačního programu: CZ.1.07 Operační program : Vzdělávání pro konkurenceschopnost Název výzvy: Středočeský kraj Výzva č.3 pro GP - oblast podpory 1.1 Název prioritní osy: Počáteční vzdělávání Název oblasti podpory: Zvyšování kvality ve vzdělávání Registrační číslo: CZ.1.07/1.1.06/

How Old Is the Grand Canyon? Part II The Grand Canyon may be 10 million years older than we thought

Vocabulary New Research Led - veden Allowed - dovolit Rafted - raftovat Hiked - vystupovat Caves - jeskyně

New Research In 2008, Victor Polyak led a team of geologists from the University of Mexico to conduct new research on the Grand Canyon. They also tested minerals that line the canyon walls at different heights in order to track water levels, which allowed them to find the rate at which the canyon deepened. Polyak and his team, however, rafted, hiked, and climbed to access caves that dot the canyon's walls. Many of the caves were difficult to reach—some were hundreds of feet high. In the caves they found mineral deposits that contain larger amounts of uranium.

Vocabulary What are mammillaries Deposits - klást, uložit Surface - povrch Formations - formace Stalagmite - krápník

What are mammillaries? The uranium-rich mineral deposits are called mammillaries. Mammillaries are mineral deposits that form at the top of the water table and provide a timeline of the river and canyon’s history. Mammillaries, often called "cave clouds," form just under the surface of water that has a high calcium-carbonate concentration. They leave behind formations, often ring-shaped as seen in trees and stalagmite, on existing rocks.

Vocabulary New birth date for the Grand Canyon Elevation - zvednutí Eroded - vymletý Suggesting - navrhovat Findings - nálezy Stream - pramen

New birth date for the Grand Canyon Polyak and his team collected mammillaries from nine sites in the Grand Canyon that were at a much higher elevation than the current water level and then used uranium-lead dating to find the age of the Grand Canyon. They found that the Grand Canyon eroded much slower on the western end than was previously thought, suggesting it is much older than six million years. Findings also showed that instead of one large river, small streams caused the erosion and they joined to make one large river, the Colorado River,which runs through the Grand Canyon today, stretching 277 river miles long, up to 18 miles wide, and a mile deep.

Questions  What are mammillanies?  Mammillanies are often called….  What caused the erosion?  How long is Colorado river?  How wide is Colorado river?  How deep is Colorado river?

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