Earth Science


EARTH SYSTEMS As you read, consider why it is important to preserve Earth’s fragile environments.


The water is warm, and you’re wearing a full wetsuit. Still, you shiver a little as you dive in. Maybe it’s from fear, or maybe it’s just from excitement. You’ve never been to an underwater cave before and don’t know what to expect from this unique landform. A cave is a natural hollow in the ground,


which is large enough for a person to enter. T is cave is a cenote, or sinkhole. It formed more than 6,500 years ago when a section of the limestone ceiling collapsed. It created a giant hole in the ground, exposing the cave filled with water underneath.


Gran Cenote, Mexico Here, divers have discovered more than


300 kilometers of interconnected, fl ooded passageways and caves. It’s like being in an underwater maze. Explorers who have gone before you have


fixed ropes into the cave walls. T ese ropes are your road map. By following the rope guidelines, you can


swim through narrow passages and large, rocky rooms without getting lost. Your tour of this cenote is only the first of many diff erent types of caves you will get to explore on this adventure.


19


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24