A lithosphere is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle are distinguished on the basis of chemistry and mineralogy.
Andesite is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predominantly of sodium-rich plagioclase plus pyroxene or hornblende.
A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian Traps. Some such volcanic regions lie far from tectonic plate boundaries, while others represent unusually large-volume volcanism near plate boundaries.
The Iceland hotspot is a hotspot which is partly responsible for the high volcanic activity which has formed the Iceland Plateau and the island of Iceland. It contributes to understanding the geological deformation of Iceland.
A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of them result from tensional forces, caused by a process known as oceanic trench rollback, where a subduction zone moves towards the subducting plate. Back-arc basins were initially an unexpected phenomenon in plate tectonics, as convergent boundaries were expected to universally be zones of compression. However, in 1970, Dan Karig published a model of back-arc basins consistent with plate tectonics.
Pyrolite is a term used to characterize a model composition of the Earth's mantle. This model is based on that a pyrolite source can produce mid-ocean ridge basalts (MORB) by partial melting. It was first proposed by Ted Ringwood (1962) as being 1 part basalt and 4 parts harzburgite, but later was revised to being 1 part tholeiitic basalt and 3 parts dunite. The term is derived from the mineral names PYR-oxene and OL-ivine. However, whether pyrolite is entirely representative of the Earth's mantle remains debated.
The Marquesas hotspot is a volcanic hotspot in the southern Pacific Ocean. It is responsible for the creation of the Marquesas Islands – a group of eight main islands and several smaller ones – and a few seamounts. The islands and seamounts formed between 5.5 and 0.4 million years ago and constitute the northernmost volcanic chain in French Polynesia.
The Society hotspot is a volcanic hotspot in the south Pacific Ocean which is responsible for the formation of the Society Islands, an archipelago of fourteen volcanic islands and atolls spanning around 720 kilometres (450 mi) of the ocean which formed between 4.5 and <1 Ma.
Ocean island basalt (OIB) is a volcanic rock, usually basaltic in composition, erupted in oceans away from tectonic plate boundaries. Although ocean island basaltic magma is mainly erupted as basalt lava, the basaltic magma is sometimes modified by igneous differentiation to produce a range of other volcanic rock types, for example, rhyolite in Iceland, and phonolite and trachyte at the intraplate volcano Fernando de Noronha. Unlike mid-ocean ridge basalts (MORBs), which erupt at spreading centers (divergent plate boundaries), and volcanic arc lavas, which erupt at subduction zones (convergent plate boundaries), ocean island basalts are the result of intraplate volcanism. However, some ocean island basalt locations coincide with plate boundaries like Iceland, which sits on top of a mid-ocean ridge, and Samoa, which is located near a subduction zone.
The Luzon Volcanic Arc is a chain of volcanoes in a north–south line across the Luzon Strait from Taiwan to Luzon. The name "Luzon Volcanic Arc" was first proposed by Carl Bowin et al. to describe a series of Miocene to recent volcanoes due to eastward subduction along the Manila Trench for approximately 1,200 km from the Coastal Range in Taiwan south to southern Mindoro in the Philippines. Islands that form part of the arc are the Eastern Coastal Range of Taiwan, Green Island, Taiwan, Orchid Island, Kaotai Rock, Mavudis or Y'ami Island, Mabudis, Siayan Island, Itbayat Island, Diogo Island, Batan Island, Unnamed volcano Ibuhos, Sabtang Island, Babuyan, Didicas, and Camiguin de Babuyanes. At the south end it terminates on Luzon. The geochemistry of a number of volcanoes along the arc have been measured. There are five distinct geochemical domains within the arc. The geochemistry of the segments verified that the volcanoes are all subduction related. Isotopes and trace elements show unique geochemical characteristics in the north. Geochemical variations northward were due to the subduction of sediments derived from the erosion of continental crust from China and Taiwan.
Crustal recycling is a tectonic process by which surface material from the lithosphere is recycled into the mantle by subduction erosion or delamination. The subducting slabs carry volatile compounds and water into the mantle, as well as crustal material with an isotopic signature different from that of primitive mantle. Identification of this crustal signature in mantle-derived rocks is proof of crustal recycling.
Provenance in geology, is the reconstruction of the origin of sediments. The Earth is a dynamic planet, and all rocks are subject to transition between the three main rock types: sedimentary, metamorphic, and igneous rocks. Rocks exposed to the surface are eventually broken down into sediments. Sediments are expected to be able to provide evidence of the erosional history of their parent source rocks. The purpose of provenance study is to restore the tectonic, paleo-geographic and paleo-climatic history.
Hollister Ridge is a group of seamounts in the Pacific Ocean. They lie west from the Pacific-Antarctic Ridge and form three ridges that form a line; one of the ridges rises to a depth of 100 metres (330 ft) and in the past formed an island. The seamounts are composed out of basaltic and other rocks and their ages range from about 2.5 million years ago to latest Pleistocene; an acoustic swarm recorded in the southern Pacific Ocean in 1991-1992 is considered to be the manifestation of a historical eruption of the Hollister Ridge.
Roberta L. Rudnick is an American earth scientist and professor of geology at the University of California, Santa Barbara. She was elected a member of the National Academy of Sciences in 2010 and was awarded the Dana Medal by the Mineralogical Society of America. Rudnick is a world expert in the continental crust and lithosphere.
The South China Craton or South China Block is one of the Precambrian continental blocks in China. It is traditionally divided into the Yangtze Block in the NW and the Cathaysia Block in the SE. The Jiangshan–Shaoxing Fault represents the suture boundary between the two sub-blocks. Recent study suggests that the South China Block possibly has one more sub-block which is named the Tolo Terrane. The oldest rocks in the South China Block occur within the Kongling Complex, which yields zircon U–Pb ages of 3.3–2.9 Ga.
Stanley Robert Hart is an American geologist, geochemist, leading international expert on mantle isotope geochemistry, and pioneer of chemical geodynamics.
Mud volcanoes in the Mariana fore-arc are a hydrothermal geologic landform that erupt slurries of mud, water, and gas. There are at least 10 mud volcanoes in the Mariana fore-arc that are actively erupting, including the recently studied Conical, Yinazao, Fantagisna, Asut Tesoro, and South Chamorro serpentinite mud volcanoes. These mud volcanoes erupt a unique serpentinite mud composition that is related to the geologic setting in which they have formed. Serpentinite mud is the product of mantle metasomatism due to subduction zone metamorphism and slab dehydration. As a result, the serpentinite mud that erupts from these mud volcanoes often contains pieces of mantle peridotite material that has not fully altered during the serpentinization process. In addition to pieces of altered mantle material, pieces of subducted seamounts have also been found within the serpentinite muds. Serpentinite mud volcanoes in the Mariana fore-arc are often located above faults in the fore-arc crust. These faults act as conduits for the hydrated mantle material to ascend towards the surface. The Mariana mud volcanoes provide a direct window into the process of mantle hydration that leads to the production of arc magmas and volcanic eruptions.
Janet Margaret Hergt is an Australian geochemist. She is a Redmond Barry Distinguished Professor in the School of Geography, Earth and Atmospheric Sciences at the University of Melbourne, Victoria, Australia. The main focus of her research has been in the chemical analysis of rocks and minerals to explore the exquisite record of Earth processes preserved within them. Hergt is best known for her geochemical investigations of magmatic rocks although she has employed similar techniques in interdisciplinary projects including areas of archaeological and biological science.
Catherine Jeandel is a French geochemical oceanographer known for her research on isotope geochemistry and trace elements in the ocean.
Asish R. Basu is a geologist, academic, and researcher. He is Professor Emeritus of Earth and Environmental Sciences at the University of Texas at Arlington. He is most known for his research in Earth Science -related subjects, such as isotope geochemistry, flood basalt volcanism, and mineralogy-petrology.
