Absolute dating volcanic ash layers

Some rock layers are surrounded by volcanic debris, or tuff, in situ, meaning they weren't broken by igneous intrusions; rather, local volcanic activity simply blanketed an area with ash at various times.

When they break and engulf chunks of sedimentary rocks, it's called stoping. The original rock layers around subsidence areas are called wall rocks and the layers that xenoliths came from are called parent rocks.However, science is suppose to do just that - challenge ideas. Because often what seems obvious initially does not turn out to be true.The scientific method is all about testing and retesting theories since no theory is ever proven by science.Igneous rocks form from eruptions of lava or magma.Metamorphic rock is formed by great pressure far below the Earth's surface.

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