Should be an easy Earthcache that teaches you a little something about the beauty of the Dakota Badlands
As you drive or hike through western North Dakota, the gently rolling hills open up dramatically into the varied and colorful layers of the badlands. Curiosity might lead you to take a closer look at the rocks making up the layers. .
The story of the badlands begins over 65 million years ago. Large amounts of sediments (sand, silt, and mud) were forming as water, wind, and freezing helped in forming the Rocky Mountains. These sediments, were carried off by rivers and deposited here in layers. Volcanoes in South Dakota, Montana, Idaho, and across the west were erupting during this time, creating huge amounts of ash. This volcanic ash was blown or carried by rivers into North Dakota and accumulated in standing water. Over time, the sediments turned into the sandstone, siltstone, and mudstone layers while the ash layers became bentonite clay.
Two million years ago, ice sheets advanced south from Canada and reaching into North Dakota. The ice blocked the flow of north-flowing rivers, forcing them to create new courses flowing east and south. meaning they emptied into the Mississippi River instead of Hudson Bay. When the ice retreated, northern portions of the Little Missouri and Missouri rivers were now entrenched in new channels. The Little Missouri’s new course was now steeper and faster, meaning it begin cutting deeply into the land. This fast flowing water cut easily through the soft sedimentary rocks, carving the topography that is today’s badlands.
Geologic processes continue to shape the badlands. Yearly precipitation in the badlands averages 15 inches. The infrequent showers usually come in heavy, erosive downpours. Water forms gullies and soaks into clay-rich rocks and soils. The area has many coal beds, which may burn for many years if ignited by lightening or prairie fires. When a coal bed burns, it bakes the overlying sediments into a hard, natural brick that geologists call clinker, or"scoria." . These hardened rocks are more resistant to erosion than the unbaked rocks nearby. Over time, erosion has worn down the less resistant rocks, leaving behind a landscape topped with durable scoria.
Information obtained from http://www.nps.gov/thro/learn/nature/geologicformations.htm At this location: Please answer these questions:
1. What is geological formation here is pastel pink? What causes the coloration?
2. The horizontal multi colored layers are composed of what three rocks?
3. What types of wood compose the petrified wood and stumps found in the badlands?
4. What causes the landscape to be ever-changing?
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