Death Valley

Death Valley 

How can we determine the direction of the seas movement that created the exposed the limestone? The rise and fall of the Cambrian seas (570-505 million years old) periodically shifted the shoreline eastward, flooding the continent, then regressed westward, exposing the limestone layers to erosion.

 

How and why did the earth stretch to a breaking point in Death Valley? Tension created by movements of Earth's tectonic plates have stretched the rocky crust Basin and Range province to the breaking point. The entire region has been pulled apart, fracturing the crust, and creating large faults. Along these north-south-trending faults mountains have uplifted and valleys down-dropped, producing the distinctive alternating pattern of linear mountain ranges and valleys of the Basin and Range province.

 

How was the Cinder cone form in Death Valley like that of the Pu`u ka Pele cinder cone? Lava erupted at 1200°C (2200°F), most of the molten, airborne globs cooled and solidified to form cinders before reaching the ground. Most cinders fell extremely near the central vent, building a small cone. How are the cone walls formed and create the slopes? Most cinders fell near the central vent. Layer upon layer of volcanic eruption were deposited, building a higher and steeper cinder cone. Eventually the cone became so steep that the flanks collapsed under their own weight. The collapsing cinders came to rest when the sides reached just the right steepness to keep them stable. This angle, usually about 35°, is called the angle of repose.

Retrieved from : http://geomaps.wr.usgs.gov/parks/deva/devaft.html.