Introduction
Four tectonic environments in which magmatism occurs: destructive plate margins, constructive plate margins/divergent plate boundaries, oceanic intraplate and continental intraplate. Arcs are magmatic products of destructive plate margins (stern, 2001) which are referred to as sites where new continental crust is created and old oceanic crust is subducted back into the mantle (Hawkesworth , Hergt, McDermott, Ellam, 1991). An island arc is a form of an arc produced by the subduction of an oceanic plate beneath another oceanic plate (Hu, 2013). Island arcs are characterised by high large ion lithophile elements and low high field strength elements ((Hawkesworth , Hergt, McDermott, Ellam, 1991). New oceanic crust is created at the mid ocean ridges and by mass balance is then destroyed (recycled back into the mantle) at the subduction zones (Jarred, 2003). As it forms it undergoes hydrothermal alteration where the composition is changed from olivine, plagioclase and glass dominated to being dominated by clay minerals i.e. low grade metamorphism (green schist facies) (Jarred, 2003) where it becomes enriched in water, carbon dioxide and incompatible trace elements such as uranium and potassium. As the crust moves away from the ridge it accumulates sediments and becomes colder, older and dense enough to subduct. As the cold slab subducts into the hot mantle, it heats up. The slab goes to greater depths faster than it’s heated therefore pressure increases therefore hydrous minerals start to break down (Aizawa, Tatsumi, Yamada, 1999). The slab undergoes metamorphic reactions from hydrous green schist facies to amphibolite facies and finally to anhydrous eclogite facies at depths of less than 100 km (Ringwood, 1977). ...
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... Leeman1, Dante Canil2, Zheng-Xue A Li ; 2005; Similar V/Sc Systematics in MORB and Arc Basalts: Implications for the Oxygen Fugacities of their Mantle Source Regions; Journal of petrology; volume 46; number 11; pages 2313-2336
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The Starved Rock Member of the Saint Peter Sandstone is preserved as a northeast-southwest trending belt of strata that is ...
Plummer, C.C., McGeary, D., and Carlson, D.H., 2003, Physical geology (10th Ed.): McGraw-Hill, Boston, 580 p.
and Metamorphic rocks can be found. There are also a lot of crusted plates, and violent
P.Wellman, Ian McDougal,(1974),Cainozoic igneous activity in Eastern Australia, Research School of Earth Sciences, ANU Canberra, Elsevier Scientific Publishing Company,pg 52
Villaros, A., Stevens, G., Moyen, J. & Buick, I.S. 2009, "The trace element compositions of S-type granites: evidence for disequilibrium melting and accessory phase entrainment in the source", Contributions to Mineralogy and Petrology, vol. 158, no. 4, pp. 543-561.
They examined how much iron, molybdenum and other metals were in the environments. “These proxies seemed to indicate that oxygen concentrations in the oceans rose in several steps, approaching today's sea-surface concentrations at the start of the Cambrian, around 541 million years ago — just before more-modern animals suddenly appeared and diversified. This supported the idea of oxygen as a key trigger for the evolutionary explosion ”(Fox).
Convection currents deep in the mantle of the earth, begin to well up towards the surface. As the pressure increases, it sets the crustal plates in motion. There are different kinds of mountains - Volcanic, Folded, Fault-block, and Dome mountains. Volcanic mountains are formed when magma comes up through cracks in the Earth’s crust and explodes out of lava and ash. The Hawaiian volcanoes, Mt. Hood, Mt. Etna, Vesuvius, and Mt. Saint Helens is an example of volcanic mountains.
Strata, which have contained fossils in the past, are sharply defined layers that differentiate between sedimentary rocks. Although evolutionists struggle to explain why strata have such unusual characteristics, Brown’s idea of liquefaction describes why they are found in strata. The reason why fossils and strata do not form in large scale quantities today is also due to liquefaction. Liquefaction greatly sorted out all of the layers of sediments and rock, and this is why strata are organized. Without the Flood, which caused global liquefaction, strata would not be as common.
Using the topics provided in the course syllabus, I came up with three categories in total.
The most dramatic expression of tectonism is mountainous topography, which is either generated along continental margins by collisions between the slablike plates that make up the Earth's lithosphere or formed somewhat farther inland by rifting and faulting. Far more subtle tectonic expressions are manifested by the vast continental regions of limited relief and elevation affected by gentle uplift, subsidence, tilting, and warping. The denudational processes act upon the tectonic "stage set" and are able to modify its features in a degree that reflects which forces are dominant through time. Volcanism as a syn-tectonic phenomenon may modify any landscape by fissure-erupted flood basalts capable of creating regional lava plateaus or by vent eruptions that yield individual volcanoes.
The partition coefficient of the metals with the melt determines which element will prefer to stay in the melt or move from the melt. Therefore, this describes the Behaviour of metals during partial melting and fractionation crystallization. The partition coefficient depends on pressure, the composition of the solid, the composition of the melt and the temperature. The results that are discussed above indicate that melt of are clinopyroxene rich rocks are expected to have low Mn/Fe, Co/Fe, Ni/Co, Mn/Zn and high Zn/Fe compared to peridotite(Olivine + othopyroxene) partial melts. Throughout the process of fractional crystallization the metals (Pb, Zn and Mo) partition into crystallizing minerals or remain dissolved in the melt.
The concurrent convective circulations in the mantle leads to some segments of the mantle moving on top of the outer core which is very hot and molten in nature. This kind of movement in different segments occurs as tectonic plates. These tectonic plates are basically seven on the earth surface as major ones, although, several small ones exist also. The plates motions are characterized by varying velocities, this variance results to sub sequential collision of two plates (leading to formation of a mountain in a convergent boundary), drift of two plates (leading to formation of rifts in a divergent boundary), or parallel movement in a transform boundary(Webcache 3).
The earliest outcropping volcanic deposits date back to about 25,000 years ago. The lavas observed at a -1125 m bore-hole are about 0,3-0,5 million years old. It is known for the first eruption of which an eyewitness account is preserved, in 79 AD. Geologically, Vesuvio is unique for its unusual versatility. Its activity ranging from Hawaiian-style release of liquid lava, fountaining and lava lakes, over Strombolian and Vulcanian activity to violently explosive, plinian events that produce pyroclastic flows and surges.