Island Arc

Island arc volcanic rocks and MORB

[Name of Student]

Island arc volcanic rocks and MORB

Introduction

The topic under study is based on the people's perception by comparison of Fe (3+)/Fe (2+) in Island arc volcanic rocks and MORB. People conclude that mantle wedge is more oxidized than mantle source of MORB. The study includes exploratory evidences in favor of or against people's conclusion.

The topic relates to geothermal studies. Geothermal areas can be classified into high temperature and low temperature, based either directly on subsurface water temperatures or indirectly on the geological settings. High-temperature geothermal areas have water temperatures in the uppermost 1,000 m (meters) of greater than 200°C. Low- temperature geothermal areas are characterized by water temperatures ranging from close to 20 to 150°C and can be found in formerly active volcanic regions, on the margins of active volcanic regions, or in areas where there is a deep component of groundwater flow, combined with geological features, such as faults or fracturing, that allow the upward movement of heated water to the surface (Arnórsson, 1995, p.561).

High-temperature geothermal areas form where there is a high-temperature gradient due to the presence of a shallow magma body (typically at around 15-5 km [kilometers], i.e., 9-3 mi. [miles] depth). Because groundwater at depth is subjected to greater pressures than shallow groundwater, it can remain in a liquid state while reaching temperatures greater than 100°C. Consequently, in high-temperature geothermal areas, groundwater typically reaches temperatures of around boiling point at 1 km (0.6 mi.) depth, and it can reach temperatures of more than 350°C at 3 km (2 mi.) depth. Groundwater that is heated at depth becomes less dense and rises to the surface.

Discussion

Island Arc Volcanic Rock

An island arc is, in geography, an island created by the subduction of oceanic tectonic plate under another. On the etymological point of view, geography is the study of Earth's surface. The word, invented by Eratosthenes for a book now lost, comes from the Greek. An archipelago is a group of islands relatively close to each other, created by the subduction. Subduction is the process of penetration of a tectonic plate under another plate of lower density, usually an oceanic plate under a continental plate or in an oceanic plate. Tectonic plates or lithospheric plates are pieces of the lithosphere resulting from its cutting like a puzzle with a fault system in a different ocean (Renaut & Jones, 2003, p.151).

When two oceanic plates meet, they pass under the younger subduction and continue its descent along a plane of inclination. When the plate reaches about 100 km depth, the conditions of temperature and pressure allow fusion. In physics and metallurgy, fusion is the passage of a body from a solid to a liquid state (Renaut & Jones, 2003, p.151). Hydration is permitted by the rise of the water in the descending plate. This water is a simple chemical compound, but with complex properties which have a share of water to Wed marine sediments present in the plate, but above the water outlet ...