Over the last 4 billion years.
Over the last 4 billion years.
Rocks in continental crust can be as old as 4 billion years. This is because continental crust is much older than oceanic crust due to its formation through various geological processes over long periods of time. The oldest rocks found on Earth are typically located in the continental crust.
Molecular Clock
Rhyolite has probably been around as long as Earth has, or about 4.6 billion years.
The simple answer: Oceanic crust is more dense than the continental crust, so it goes under as the two plates ram into each other. (This is called subduction) This submerged crust melts into magma, and collects into a large pool under the continental plate where it went under. The pool of magma forces its way up to form a volcano, which sits in front of us and blows when least expected. The whole process takes a very long time. Also, it only happens in convergent boundaries.
evolving independently
molecular clocks
The crust is the outermost layer of the Earth, which is thin and solid. It is divided into continental crust (underneath land) and oceanic crust (underneath oceans). In contrast, the mantle is the layer beneath the crust and is primarily composed of solid rock that flows slowly over long periods of time.
The marching band we know today branches out from drum and bugle corps which began performing field shows around the 1970's. However marching band has been evolving for centuries. Starting with traveling musicians and then evolving into military practice, marcging band has been evolving into what it is today for a very long time.
The tectonic plate movement forms folds in the land over long expansions of time, therefore creating mountains. If you have a continental mountain range, the tectonic plate movement has been moving in that area for a long time.
the mantle then the outer core then the inner core
The major layers of Earth's geosphere are the crust, mantle, and core. The crust is the outermost layer and is divided into oceanic and continental crust. The mantle is situated beneath the crust and is composed of solid rock that can flow slowly over long periods of time. The core is located at the center of the Earth and is divided into the outer liquid outer core and the solid inner core.