Water-induced Weakening of Hornblende and Amphibolite

Riecker, Robert E.; Rooney, Thomas P.

doi:10.1038/2241299a0

Cited by 16 publications

(5 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The differential stress of deformed amphibolite under wet conditions was only ∼30 to 50% of that under dry conditions at the same temperature and strain rate ( Table 1 ). This water-induced weakening of amphibolite coincides with the results of earlier experimental studies 21 25 .…”

Section: Resultssupporting

confidence: 90%

“…Previous experimental studies of amphibolite primarily focused on the mechanical behaviour of amphibole under uniaxial compression. Water weakening of amphibolite was observed at a temperature of 800 °C and confining pressures of 0.5–2 GPa due to the dehydration reaction of hornblende 21 22 23 . The experimentally deformed amphibole in earlier studies showed a crystal plasticity at pressures of 0.5–2 GPa and temperatures of 600–800 °C (refs 23 , 24 ), with a slip system of (100)[001] and ( 1 01) twinning.…”

mentioning

confidence: 99%

“…Synthetic amphibolite was observed to deform by crystal plasticity at temperatures above 750 °C and strain rates below , whereas natural amphibolite was deformed by brittle processes under all experimental conditions. However, almost no investigations on CPO development in amphibole have been performed in previous experimental studies 21 23 25 . Particularly absent are reports on experimentally deformed amphiboles under simple shear, which is considered to be the dominant mode of deformation that forms the CPO of minerals in the crust and upper mantle 26 .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Crystal preferred orientation of an amphibole experimentally deformed by simple shear

2015

View full text Add to dashboard Cite

Seismic anisotropy has been widely observed in crust and mantle materials and plays a key role in the understanding of structure and flow patterns. Although seismic anisotropy can be explained by the crystal preferred orientation (CPO) of highly anisotropic minerals in the crust, that is, amphibole, experimental studies on the CPO of amphibole are limited. Here we present the results of novel experiments on simple shear deformation of amphibolite at high pressure and temperatures (1 GPa, 480–700 °C). Depending on the temperature and stress, the deformed amphibole produced three types of CPOs and resulted in a strong seismic anisotropy. Our data provide a new understanding of the observed seismic anisotropy. The seismic data obtained from the amphibole CPOs revealed that anomalous seismic anisotropy observed in the deep crust, subducting slab and mantle wedge can be attributed to the CPO of amphibole.

show abstract

Section: Resultssupporting

confidence: 90%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Crystal preferred orientation of an amphibole experimentally deformed by simple shear

2015

View full text Add to dashboard Cite

show abstract

“…Summers and Byerlee, 1977). Riecker and Rooney (1969) and Murrell and Ismail (1976) found similar effects in the experimental deformation and dehydration of amphibole and chlorite, respectively. All of these examples illustrate interrelationships of type (a) above.…”

Section: Examples Of Experimental Studiesmentioning

confidence: 65%

Experimental approaches to the study of deformation/metamorphism relationships

Rutter

Brodie

1988

Mineral. mag.

View full text Add to dashboard Cite

Rock deformation and metamorphism can interact at the mechanistic level in the following ways: (a) facilitation of cataclasis through the release of high-pressure fluid during dehydration and decarbonation reactions; (b) facilitation of intracrystalline plasticity through the stresses induced during solid-state volume changes; (c) enhanced deformability through the transient existence of fine-grained reaction products; (d) modification of chemical potential gradients driving diffusion if a reaction can occur along the diffusion path; (f) changes in the resistance to intracrystalline plasticity through the effect of reaction-induced changes, pore fluid pressure and chemistry on point defect chemistry of the solid phases.Examples of experimental studies of each of these types of interaction are described. Special experimental problems arise through: (i) the effects of solid phase and pore space volume changes, and their effects on pore fluid pressure and measured strain; (ii) the effects of such microstructural changes on the determination of flow law parameters; and (iii) in many instances the need for very long duration deformation experiments if reaction kinetics are sluggish.There is an outstanding need for experimental studies of the effects of non-hydrostatic stress on the conditions for the onset of metamorphic reactions and phase transformations, as a basis for understanding some classes of deformation/metamorphism interaction. However, it is emphasized that the threefold classification of rock deformation mechanisms into cataclastic, crystal-plastic, and diffusive mass transfer processes, established from the study of deformation of monomineralic rocks, forms an essential framework for the understanding of deformation/metamorphism inter-relationships.

show abstract

“…However, xenolith studies suggest that the added volatiles are usually taken up in amphibole overgrowths on clinopyroxene, rather than being incorporated into olivine, and, thus, will lower the solidus of the peridotite by several hundred degrees Celsius relative to that of anhydrous peridotite (Olafsson & Eggler 1983). Although appropriate experimental data are limited, it seems likely that amphibole (Riecker & Rooney 1969) will be just as strong as clinopyroxene (Kirby & Kronenberg 1984), and so there is as yet little reason to think that volatile-enriched major-element-depleted peridotite should be any weaker than normal anhydrous fertile peridotite (Turner & Hawkesworth 1995). On the contrary, the increased thickness and resultingly cooler geotherm, and the opx-rich mineralogy, combine to make Archaean lithosphere significantly stronger than Proterozoic and younger lithosphere; a feature presumably linked to its longer survival.…”

Section: (E) Volatilesmentioning

confidence: 99%

Chemical and temporal variations in the Earth's lithosphere

Hawkesworth

Pearson

Turner

1999

Philosophical Transactions of the Royal Society of London. Seri

View full text Add to dashboard Cite

The lithosphere is the rigid outer layer of the Earth, but its composition, and by implication its origins, are different in terrains of different ages. The continental lithosphere is typically weaker, although often much thicker, than the oceanic lithosphere. Oceanic mantle lithosphere accretes new material at its base as it cools (thermal accretion), and so it is compositionally similar to the underlying asthenosphere. Much of the continental mantle lithosphere, and particularly that beneath Archaean cratons, is relatively depleted in major elements. Thus, continental mantle lithosphere is less dense than the oceanic lithosphere, and its thickness depends on the compositional difference between it and the underlying asthenosphere, as well as on the geothermal gradient. The errors and accuracy of the mineral thermobarometry of peridotite samples are briefly reviewed, and both mineral thermobarometry and heat-flow studies consistently suggest minimum thicknesses of 150-200 km for the lithosphere beneath Archaean cratons. Os isotopes reflect the age of major-element depletion, and, hence, the stabilization of the mantle lithosphere. They confirm that in many cases the continental crust and uppermost mantle stabilized at about the same time, and have remained as a coherent unit ever since. In general, areas of Archaean lithosphere appear not to have thickened significantly since they were formed, whereas the lithosphere beneath Proterozoic and younger areas has been more prone to subsequent magmatic and tectonic events.

show abstract

Water-induced Weakening of Hornblende and Amphibolite

Abstract: FUEL cells with acid electrolyte, such as dilute sulphurin acid, have the advantage over those with alkaline electrolyte that carbon dioxide is not absorbed by the electrolyte. In principle it is therefore possible to use organic fuels,

Cited by 16 publications

References 3 publications

Crystal preferred orientation of an amphibole experimentally deformed by simple shear

Crystal preferred orientation of an amphibole experimentally deformed by simple shear

Experimental approaches to the study of deformation/metamorphism relationships

Chemical and temporal variations in the Earth's lithosphere

Contact Info

Product

Resources

About