Catherine Jeanne Annen | |
---|---|
Alma mater | University of Geneva |
Awards | Bigsby Medal |
Scientific career | |
Institutions | University of Bristol University of Geneva Czech Academy of Sciences |
Thesis | Modélisation de la croissance des volcans (1999) |
Catherine Jeanne Annen is a French geologist at the Czech Academy of Sciences. Her research considers igneous bodies, volcanic eruptions. and exploration for geothermal energy. She was awarded the 2022 Geological Society of London Bigsby Medal.
Annen studied earth sciences at the University of Geneva. [1] Alongside her studies she worked as a teaching assistant on the modelling of volcanic processes. She remained in Geneva for graduate research, working partly at the Blaise Pascal University. [2] Her research considered how to model the growth of volcanoes. [3] After earning her doctorate, Annen joined the University of Bristol, where she worked on models of magma injection and incrementally emplaced intrusions. [4] [5] [6]
Annen returned to the University of Geneva in 2003, where she worked as an assistant professor.[ citation needed ] She was appointed to the faculty at the University of Bristol in 2009. [7] Her research combined numerical simulations with heat transfer models to better understand magmatic processes. [4] She was particularly interested in the genesis of differentiated melts and how pluton emplacement impacts the growth of large magma chambers. [4] She studied the Soufrière Hills and Mount Pelée. [8] [9] She uncovered the environmental circumstances that determine the frequency of volcanic activity and the magnitude of volcanic phenomena. [10] Small frequent eruptions are triggered by magma replenishment, whilst larger eruptions are caused by magma buoyancy. This buoyancy results in less frequent eruptions and is powered by the accumulation of less dense magma underneath volcanoes. [10] Her findings predict that the largest possible volcanic eruption would result in the release of 3,500 km3 of magma. [11] [12]
Annen was made Chief Editor of Frontiers in Earth Sciences in 2015. [13] In 2022 she was elected vice president of the Volcanic and igneous plumbing systems committee. [14] In 2021 Annen joined the Czech Academy of Sciences [2] where she works on the formation and differentiation of magma chambers.
Magma is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles.
A batholith is a large mass of intrusive igneous rock, larger than 100 km2 (40 sq mi) in area, that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such as granite, quartz monzonite, or diorite.
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 magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upwards. If the magma finds a path to the surface, then the result will be a volcanic eruption; consequently, many volcanoes are situated over magma chambers. These chambers are hard to detect deep within the Earth, and therefore most of those known are close to the surface, commonly between 1 km and 10 km down.
A flood basalt is the result of a giant volcanic eruption or series of eruptions that covers large stretches of land or the ocean floor with basalt lava. Many flood basalts have been attributed to the onset of a hotspot reaching the surface of the Earth via a mantle plume. Flood basalt provinces such as the Deccan Traps of India are often called traps, after the Swedish word trappa, due to the characteristic stairstep geomorphology of many associated landscapes.
In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A sill is a concordant intrusive sheet, meaning that it does not cut across preexisting rock beds. Stacking of sills builds a sill complex and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks.
The rock cycle is a basic concept in geology that describes transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous. Each rock type is altered when it is forced out of its equilibrium conditions. For example, an igneous rock such as basalt may break down and dissolve when exposed to the atmosphere, or melt as it is subducted under a continent. Due to the driving forces of the rock cycle, plate tectonics and the water cycle, rocks do not remain in equilibrium and change as they encounter new environments. The rock cycle explains how the three rock types are related to each other, and how processes change from one type to another over time. This cyclical aspect makes rock change a geologic cycle and, on planets containing life, a biogeochemical cycle.
In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of magmas produced by igneous differentiation is known as a magma series.
In geology, an igneous intrusion is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and compositions, illustrated by examples like the Palisades Sill of New York and New Jersey; the Henry Mountains of Utah; the Bushveld Igneous Complex of South Africa; Shiprock in New Mexico; the Ardnamurchan intrusion in Scotland; and the Sierra Nevada Batholith of California.
The Paraná-Etendeka Large Igneous Province (PE-LIP) (or Paraná and Etendeka Plateau; or Paraná and Etendeka Province) is a large igneous province that includes both the main Paraná traps (in Paraná Basin, a South American geological basin) as well as the smaller severed portions of the flood basalts at the Etendeka traps (in northwest Namibia and southwest Angola). The original basalt flows occurred 136 to 132 million years ago. The province had a post-flow surface area of 1,000,000 square kilometres (390,000 sq mi) and an original volume projected to be in excess of 2.3 x 106 km3.
Jonathan David Blundy FRS is Royal Society Research Professor at the School of Earth Sciences at the University of Oxford and honorary professor at the University of Bristol.
Partial melting is the phenomenon that occurs when a rock is subjected to temperatures high enough to cause certain minerals to melt, but not all of them. Partial melting is an important part of the formation of all igneous rocks and some metamorphic rocks, as evidenced by a multitude of geochemical, geophysical and petrological studies.
Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
The Altiplano–Puna volcanic complex, also known as APVC, is a complex of volcanic systems in the Puna of the Andes. It is located in the Altiplano area, a highland bounded by the Bolivian Cordillera Real in the east and by the main chain of the Andes, the Western Cordillera, in the west. It results from the subduction of the Nazca Plate beneath the South American Plate. Melts caused by subduction have generated the volcanoes of the Andean Volcanic Belt including the APVC. The volcanic province is located between 21° S–24° S latitude. The APVC spans the countries of Argentina, Bolivia and Chile.
The Deep Crustal Hot Zone (DCHZ), or just deep hot zone, is a zone in the lower crust where hot mantle material intrudes. In a volcanic arc setting, hot, molten material from the mantle may intrude into the lower crust. This hot material generates a new, more evolved melt in this area of the crust, which may collect and migrate upwards towards the upper crust. Here, it would collect in a magma chamber and later erupt.
A crystal mush is magma that contains a significant amount of crystals suspended in the liquid phase (melt). As the crystal fraction makes up less than half of the volume, there is no rigid large-scale three-dimensional network as in solids. As such, their rheological behavior mirrors that of absolute liquids.
The Altiplano-Puna Magma Body (APMB), a magma body located within the Altiplano-Puna plateau approximately 10–20 km beneath the Altiplano-Puna Volcanic Complex (APVC) in the Central Andes. High resolution tomography shows that this magma body has a diameter of ~200 km, a depth of 14–20 km, with a total volume of ~500,000 km3, making it the largest known active magma body on Earth. Thickness estimates for the APMB are varied, with some as low as 1 km, others around 10–20 km, and some extending as far down as the Moho. The APMB is primarily composed of 7-10 wt% water andesitic melts and the upper portion may contain more dacitic melts with partial melt percentages ranging from 10-40%. Measurements indicate that the region around the Uturuncu volcano in Bolivia is uplifting at a rate of ~10 mm/year, surrounded by a large region of subsidence. This movement is likely a result of the APMB interacting with the surrounding rock and causing deformation. Recent research demonstrates that this uplift rate may fluctuate over months or years and that it has decreased over the past decade. Various techniques, such as seismic, gravity, and electromagnetic measurements have been used to image the low-velocity zone in the mid to upper crust known as the APMB.
Volcanic and igneous plumbing systems (VIPS) consist of interconnected magma channels and chambers through which magma flows and is stored within Earth's crust. Volcanic plumbing systems can be found in all active tectonic settings, such as mid-oceanic ridges, subduction zones, and mantle plumes, when magmas generated in continental lithosphere, oceanic lithosphere, and in the sub-lithospheric mantle are transported. Magma is first generated by partial melting, followed by segregation and extraction from the source rock to separate the melt from the solid. As magma propagates upwards, a self-organised network of magma channels develops, transporting the melt from lower crust to upper regions. Channelled ascent mechanisms include the formation of dykes and ductile fractures that transport the melt in conduits. For bulk transportation, diapirs carry a large volume of melt and ascent through the crust. When magma stops ascending, or when magma supply stops, magma emplacement occurs. Different mechanisms of emplacement result in different structures, including plutons, sills, laccoliths and lopoliths.
Ōkataina Caldera is a volcanic caldera and its associated volcanoes located in Taupō Volcanic Zone of New Zealand's North Island. It has several actual or postulated sub calderas. The Ōkataina Caldera is just east of the smaller separate Rotorua Caldera and southwest of the much smaller Rotomā Embayment which is usually regarded as an associated volcano. It shows high rates of explosive rhyolitic volcanism although its last eruption was basaltic. The postulated Haroharo Caldera contained within it has sometimes been described in almost interchangeable terms with the Ōkataina Caldera or volcanic complex or centre and by other authors as a separate complex defined by gravitational and magnetic features.. Since 2010 other terms such as the Haroharo vent alignment, Utu Caldera, Matahina Caldera, Rotoiti Caldera and a postulated Kawerau Caldera are often used, rather than a Haroharo Caldera classification.