Kinetics of the olivine-spinel transformation in subducting lithosphere: experimental constraints and implications for deep slab processes

Rubie, D. C.; Ross, Charles R.

doi:10.1016/0031-9201(94)05070-8

Cited by 190 publications

(140 citation statements)

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“…The state of stress and temperature in different slabs are related to the convergence rates and the thermal gradients of slabs (8,28). If a subducting slab is subjected to a higher temperature and stress, the {101} planar defects might be produced in large grains of olivine, and these defects subsequently would act as nucleation sites for ringwoodite lamellae.…”

Section: Discussionmentioning

confidence: 99%

“…N atural ringwoodite had been found in many shocked chondritic meteorites, in which the ringwoodite occurs as finegrained polycrystalline aggregates formed through a phase transition of olivine during exogenous dynamic events on the parent asteroids (1)(2)(3)(4). It was also suggested that the olivineringwoodite transformation could take place in cold subducting slabs at the deep transition zone, where pressure oversteps the ringwoodite stability field (5)(6)(7)(8)(9)). An experiment-produced texture characteristic of this phase transition in the slabs is the formation of ringwoodite lamellae within individual olivine crystals (6,7,(10)(11)(12).…”

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confidence: 99%

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Ringwoodite lamellae in olivine: Clues to olivine–ringwoodite phase transition mechanisms in shocked meteorites and subducting slabs

Chen

Goresy

Gillet

2004

Proc. Natl. Acad. Sci. U.S.A.

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The first natural occurrence of ringwoodite lamellae was found in the olivine grains inside and in areas adjacent to the shock veins of a chondritic meteorite, and these lamellae show distinct growth mechanism. Inside the veins where pressure and temperature were higher than elsewhere, ringwoodite lamellae formed parallel to the {101} planes of olivine, whereas outside they lie parallel to the (100) plane of olivine. The lamellae replaced the host olivine from a few percent to complete. Formation of these lamellae relates to a diffusion-controlled growth of ringwoodite along shear-induced planar defects in olivine. The planar defects and ringwoodite lamellae parallel to the {101} planes of olivine should have been produced in higher shear stress and temperature region than that parallel to the (100) plane of olivine. This study suggests that the time duration of high pressure and temperature for the growth of ringwoodite lamellae might have lasted at least for several seconds, and that an intracrystalline transformation mechanism of ringwoodite in olivine could favorably operate in the subducting lithospheric slabs in the deep Earth. N atural ringwoodite had been found in many shocked chondritic meteorites, in which the ringwoodite occurs as finegrained polycrystalline aggregates formed through a phase transition of olivine during exogenous dynamic events on the parent asteroids (1-4). It was also suggested that the olivineringwoodite transformation could take place in cold subducting slabs at the deep transition zone, where pressure oversteps the ringwoodite stability field (5-9). An experiment-produced texture characteristic of this phase transition in the slabs is the formation of ringwoodite lamellae within individual olivine crystals (6,7,(10)(11)(12). A number of laboratory experiments on compositions like Mg 2 GeO 4 , Fe 2 SiO 4 , and (Mg,Fe) 2 SiO 4 showed that the spinel-structured lamellae lie parallel to the (100) planes of olivine (6,(10)(11)(12)(13)(14)(15)(16)(17)(18). These ringwoodite lamellae form platelets from several unit cells to 100 nm in thickness (6,(10)(11)(12)(14)(15)(16)(17)(18). The formation of ringwoodite lamellae in olivine was attributed either to a martensitic transformation mechanism (6,13,(15)(16)(17)(18)(19) or an intracrystalline nucleation and growth mechanism by which coherent nucleation of ringwoodite occurs on the stacking faults of olivine (10-12). However, no natural occurrence of ringwoodite lamellae had been found so far either in the shocked meteorites or exhumed subducted slabs.Sixiangkou meteorite is a heavily shock-metamorphosed L6-chondrite with a number of shock-produced veins up to 10 mm in thickness. The shock veins contain abundant high-pressure minerals including ringwoodite, majorite, garnet, and magnesiowüstite, for which the shock-produced pressure and temperature of Ϸ20 GPa and 2,000°C were inferred (4). Polycrystalline aggregates of ringwoodite and majorite up to 100 m in size and porphyroclastic grains of olivine and pyroxene up to 1.5 mm in size distr...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Ringwoodite lamellae in olivine: Clues to olivine–ringwoodite phase transition mechanisms in shocked meteorites and subducting slabs

Chen

Goresy

Gillet

2004

Proc. Natl. Acad. Sci. U.S.A.

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“…For geological applications, this equation has been used to model the rate of olivine~-y phase transformation in the mantle (e.g. Rubie and Ross, 1994).…”

Section: The Avrami Equationmentioning

confidence: 99%

Kinetic processes of mantle minerals

Koga¹

1999

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This dissertation discusses the experimental results designed to constrain the processes of MORE generation. The main focus of this study is to investigate the location and the related processes of the transformation boundary from spinel to garnet peridotite facies at subsolidus conditions, because the presence of garnet in melting residues has significant influence to the conclusion drawn from geochemical/geophysical observations. Using an approach that monitors the rate of reaction progresses, the experimental results confirmed the presence of a region that garnet and spinel coexist in peridotite compositions. The trace element distribution among the product phases (opx and cpx) subsequent to the garnet breakdown reaction is in disequilibrium, due to the differences of diffusivity between major and trace elements. The presence of disequilibrium distribution in nature may be used to infer time scales of geodynamic processes. Diffusion coefficients of Al in diopside are experimentally determined, and used for modeling the equilibration of major elements in pyroxene during MORE genesis. In summary, this dissertation contributes two major inferences: the location of the transformation boundaries of the gamet-spinel peridotite; the presence of disequilibrium trace elements distribution with equilibrium major elements distribution in mantle pyroxenes.3

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“…The A major difficulty in attempting to image metastable olivine is the anticipated narrow thickness of the wedge. Thermal models of slabs combined with a kinetic model of the olivine-spinel transformation predict that metastable wedges of olivine are relatively small-scale features [Rubie and Ross, 1994;Kirby et al, 1996;Dassler and Yuen, 1996]. At depths of 500 km the width of such a wedge might be of the order of only 20-50 km for quickly subducting slabs, and not exist at all for slowly subducting slabs [Kirby et al, 1996].…”

Section: Introductionmentioning

confidence: 99%

Modeling the Tonga slab: Can travel time data resolve a metastable olivine wedge?

Koper¹,

Wiens²,

Dorman³

et al. 1998

J. Geophys. Res.

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Abstract. We present the results of detailed modeling of the Tonga slab with the goals of determining whether high-resolution travel time data (1) can be fit by simple thermal and petrological slab models and (2) can resolve a metastable olivine wedge at depths greater than the equilibrium olivine-spinel phase boundary. We model arrival times recorded by a 1000 km line of 23 ocean bottom seismometers (OBS) and island broadband seismic stations extending from the Lau backarc basin, across the Tonga trench and onto the Pacific plate. The data consist of 388 local, P wave travel times from 17 deep and 3 intermediate earthquakes recorded during the 3-month OBS deployment in late 1994. We locate the events using both local and teleseismic arrival times, and apply a relocation operator to the theoretical travel times to simulate the biases introduced in the data by locating the events with a reference Earth model. The modeling consists of grid searches using a three-dimensional finite difference algorithm to compute local, first arriving travel times for equilibrium and metastable P wave velocity models constructed from thermal, mineralogical, and morphological constraints. The travel time anomalies are well fit by standard slab thermal models and P velocity temperature derivatives of-0.4 to -0.3 ms'•øC -•. Forward calculations indicate that the presence of a metastable olivine wedge has a subtle effect on the travel times due to the tendency of first arriving waves to avoid the low-velocity region. Wedge velocity models provide a slightly better fit to the data than equilibrium models, but F tests indicate the improvement is not significant at the 95% level. Our results suggest that providing direct seismological evidence of a wedge of metastable olivine in subduction zones will require either waveform modeling or the observation of later arriving phases created by the depressed phase boundary.

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Kinetics of the olivine-spinel transformation in subducting lithosphere: experimental constraints and implications for deep slab processes

Cited by 190 publications

References 38 publications

Ringwoodite lamellae in olivine: Clues to olivine–ringwoodite phase transition mechanisms in shocked meteorites and subducting slabs

Ringwoodite lamellae in olivine: Clues to olivine–ringwoodite phase transition mechanisms in shocked meteorites and subducting slabs

Kinetic processes of mantle minerals

Modeling the Tonga slab: Can travel time data resolve a metastable olivine wedge?

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