What is an ophiolite complex?
Ophiolite is a stratified igneous rock complex composed of upper basalt member, middle gabbro member and lower peridotite member (Fig. 1). Some large complexes measure more than 10 km thick, 100 km wide and 500 km long. The term “ophiolite” means “snake stone” in Greek.
What is ophiolite used for?
Since the late 1970s, the term ophiolite has been used to describe sections of oceanic crust and upper mantle, along with sedimentary rocks deposited on the sea floor, emplaced as thrust slices onto continental lithosphere .
What ophiolite means?
Ophiolite is thrust sheets of ancient oceanic crust and upper part of mantle rocks that have been uplifted and exposed above sea level and often emplaced on top of the continental lithosphere.
Where are deep sea trenches found quizlet?
What are deep-ocean trenches? Long, narrow creases in the seafloor representing the deepest parts of the ocean floor. Most are located along the margins of the Pacific Ocean, with only two being located in the Atlantic.
What is special about Dunite?
Dunite is an ultramafic plutonic rock that is composed almost exclusively of olivine. “Ultramafic” means that mafic minerals form more than 90% on the rocks composition. Peridotite that contains more than 90% olivine have a special name, they are called dunite (named in 1864 after Dun mountain in New Zealand).
What is an accretionary wedge made of?
Most of the material in the accretionary wedge consists of marine sediments scraped off from the downgoing slab of oceanic crust, but in some cases the wedge includes the erosional products of volcanic island arcs formed on the overriding plate.
Where does seafloor spreading occur?
Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.
How big are the large complexes of ophiolites?
Some large complexes measure more than 10 km thick, 100 km wide and 500 km long. The term “ophiolite” means “snake stone” in Greek. Basalt and gabbro are commonly altered to patchy green rocks, and peridotite is mostly changed into black, greasy serpentinite.
Is the ophiolite a mantle or mantle rock?
Ophiolite is the thrust sheets of ancient oceanic crust and upper part of mantle rocks that has been uplifted and exposed above sea level and often emplaced on top of the continental lithosphere.
How big are the ophiolite-hosted diamonds?
Ophiolite-hosted diamonds mainly range from colorless to light yellow. Most of them are 50–500 μm in size, with a few as large as 700 μm ( Lian and Yang, 2019).
What does the term ophiolite mean in Greek?
The term “ophiolite” means “snake stone” in Greek. Basalt and gabbro are commonly altered to patchy green rocks, and peridotite is mostly changed into black, greasy serpentinite.
