The 10Å phase: a high-pressure expandable sheet silicate stable during subduction of hydrated lithosphere

Fumagalli, P.; Stixrude, Lars; Poli, Stefano; Snyder, Don

doi:10.1016/s0012-821x(01)00238-2

Cited by 105 publications

(63 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The strongest of three weak single bands in the OH stretching mode region (Fig. 7d) is also consistent with the spectrum of talc (Fumagalli et al 2001). This interpretation supports NMR observations by MacKenzie and Meinhold (1994) who proposed a talc-like structure for their dehydroxylate II phase.…”

Section: Dehydroxylation Products: a Talc-like Intermediate And Forstsupporting

confidence: 84%

“…Supported by a band appearing at 1000 cm -1 (690 C) it is possible to assign them as Raman bands related to talc as reported by Fumagalli et al (2001). The bands located at 670 and 1000 cm -1 are also observable in the spectrum of the quenched dehydroxylated sample, where they are shifted to 686 and 1021 cm -1 , respectively.…”

Section: Dehydroxylation Products: a Talc-like Intermediate And Forstsupporting

confidence: 59%

“…The bands located at 670 and 1000 cm -1 are also observable in the spectrum of the quenched dehydroxylated sample, where they are shifted to 686 and 1021 cm -1 , respectively. Referring to Fumagalli et al (2001) (Fig. 5d) and one Si-O stretching mode represented by the 1000 cm -1 feature at 819 C and 1021 cm -1 , respectively, in the spectra of the quenched sample.…”

Section: Dehydroxylation Products: a Talc-like Intermediate And Forstmentioning

confidence: 97%

See 2 more Smart Citations

In situ high-temperature Raman and FTIR spectroscopy of the phase transformation of lizardite

Trittschack¹,

Grobéty²,

Koch‐Müller³

2012

American Mineralogist

View full text Add to dashboard Cite

A temperature-dependent in situ micro-FTIR and micro-Raman spectroscopic investigation was performed on powdered (FTIR, Raman) and single-crystal (Raman) lizardite-1T samples between room temperature and 819 °C. Between room temperature and 665 °C, the OH stretching bands shift to lower wavenumbers, demonstrating a weak expansion of the O3-H3 … O2 interlayer distance. Band deconvolution of FTIR and Raman spectra at room temperature show differences in the number of bands in the OH stretching region with respect to group theory: four (FTIR) and six (Raman) OH stretching bands, respectively. This number reduces to four (Raman) at non-ambient temperatures either caused by LO-TO splitting, the presence of non-structural OH species or the presence of different lizardite polytypes and/or serpentine polymorphs as well as defects. During dehydroxylation, the evolution of the integrated intensity of the OH bands suggests a transport of hydrogen and oxygen as individual ions/molecule or OH -. A significant change in Raman spectra occurs between 639 and 665 °C with most lizardite peaks disappearing contemporaneously with the appearance of forsterite-related features and new, non-forsterite bands at 183, 350, and 670 cm -1 . A further band appears at 1000 cm -1 at 690 °C. The long stability of Si-O-related bands indicates a delayed decomposition of the tetrahedral sheet with respect to the dehydroxylation of the octahedral sheet. Moreover, evidence for a small change in the ditrigonal distortion angle during heating is given. In general, all appearing non-forsterite-related frequencies are similar to Raman data of talc and this indicates the presence of a talc-like intermediate.

show abstract

Section: Dehydroxylation Products: a Talc-like Intermediate And Forstsupporting

confidence: 84%

Section: Dehydroxylation Products: a Talc-like Intermediate And Forstsupporting

confidence: 59%

Section: Dehydroxylation Products: a Talc-like Intermediate And Forstmentioning

confidence: 97%

See 1 more Smart Citation

In situ high-temperature Raman and FTIR spectroscopy of the phase transformation of lizardite

Trittschack¹,

Grobéty²,

Koch‐Müller³

2012

American Mineralogist

View full text Add to dashboard Cite

show abstract

“…The appearance of a new OH band at 3677 cm -1 (quenched sample), which is the only visible OH stretching band after heating the sample to 768 C, is an indication for the formation of an intermediate phase other than the ill-crystallized primary product and forsterite. This single OH band is compatible with the OH band position of talc at RT (Fumagalli et al 2001), an interpretation strongly supported by newly formed bands in the low-frequency range and discussed in detail in the following section. The lack of this OH band at 871 C and in the spectrum of the subsequently quenched sample indicates that this intermediate breaks down between 768 and 871 C.…”

Section: The Chrysotile Phase Transformation As Seen In the Oh Stretcsupporting

confidence: 80%

“…But, less is documented about the relation of the lizardite and chrysotile breakdown including the formation of a talc-like intermediate. Additional studies are important to unravel the complex association between primary serpentine minerals, the talc-like phase, talc, and the 10 Å phase (Fumagalli et al 2001;Chollet et al 2009) in the MSH system. Moreover, a talc-like phase offers potential nucleation sites of carbonate bearing phases in carbon capture and sequestration experiments.…”

Section: The Chrysotile Phase Transformation As Seen In the Oh Stretcmentioning

confidence: 99%

The dehydroxylation of chrysotile: A combined in situ micro-Raman and micro-FTIR study

Trittschack

Grobéty

2013

American Mineralogist

View full text Add to dashboard Cite

One of the most important mechanisms releasing water in subducting slabs of oceanic crust is connected to the dehydration of serpentinized oceanic rocks. This study reports on a detailed investigation of the transition from chrysotile-an important serpentine mineral-to forsterite through the release of water.The dehydroxylation of natural chrysotile and the subsequent phase change to forsterite was studied by in situ micro-Raman and micro-FTIR spectroscopy in the temperature range of 21 to 871 C. Comparisons were made with previously published data of lizardite-1T. Micro-Raman spectra obtained in the low-frequency (100-1200 cm -1 ) and high-frequency ranges (3500-3800 cm -1 ) were complemented by micro-FTIR measurements between 2500 and 4000 cm -1 to study changes in the chrysotile structure as a function of dehydroxylation progress. In general, room-temperature chrysotile bands lie at higher wavenumbers than equivalent bands of lizardite-1T except of three bands positioned at 301.7, 317.5, and 345.2 cm -1 . Different band assignments of chrysotile and lizardite-1T Raman spectra from literature are compared. The most striking assignments concern the three aforementioned Raman bands and those lying between 620 and 635 cm -1 . The present data support a chrysotile-or at least curved TO layer related origin of the latter. Deconvolution of overlapping OH stretching bands at room temperature revealed the presence of five (FTIR) and four (Raman) bands, respectively. A slight change in the ditrigonal distortion angle during heating and the effects of a radius-dependent dehydroxylation progress can be shown. Furthermore, it was possible to identify a quenchable talclike phase immediately after the onset of the dehydroxylation at 459 C. Main bands of this phase are positioned at 184.7, 359.2, and 669.1 cm -1 and a single OH band at 3677 cm -1, and are thus quite similar to those reported for dehydroxylating lizardite-1T. Their appearance coincides with the formation of forsterite. A maximum in the integral intensity of the talc-like intermediate is reached at 716 C. At higher temperatures, the intermediate phase breaks down and supports the accelerated growth of forsterite. The lack of OH bands with the concomitant appearance of broad chrysotile-related modes in the low-frequency range after heating the sample to 871 C indicates the presence of a heavily disordered phase still resembling chrysotile. However, there are no spectral evidences for further Si-and/ or Mg-rich amorphous phases during the dehydroxylation and no indications for a relationship between the breakdown of the talc-like phase and the growth of enstatite as previously reported in literature.

show abstract

Deep water recycling through time

Magni

Bouilhol

Hunen

2014

Geochem Geophys Geosyst

View full text Add to dashboard Cite

We investigate the dehydration processes in subduction zones and their implications for the water cycle throughout Earth's history. We use a numerical tool that combines thermo-mechanical models with a thermodynamic database to examine slab dehydration for present-day and early Earth settings and its consequences for the deep water recycling. We investigate the reactions responsible for releasing water from the crust and the hydrated lithospheric mantle and how they change with subduction velocity (vs), slab age (a) and mantle temperature (Tm). Our results show that faster slabs dehydrate over a wide area: they start dehydrating shallower and they carry water deeper into the mantle. We parameterize the amount of water that can be carried deep into the mantle, W (×105 kg/m2), as a function of vs (cm/yr), a (Myrs), and Tm (°C):. We generally observe that a 1) 100°C increase in the mantle temperature, or 2) ∼15 Myr decrease of plate age, or 3) decrease in subduction velocity of ∼2 cm/yr all have the same effect on the amount of water retained in the slab at depth, corresponding to a decrease of ∼2.2×105 kg/m2 of H2O. We estimate that for present-day conditions ∼26% of the global influx water, or 7×108 Tg/Myr of H2O, is recycled into the mantle. Using a realistic distribution of subduction parameters, we illustrate that deep water recycling might still be possible in early Earth conditions, although its efficiency would generally decrease. Indeed, 0.5–3.7 × 108 Tg/Myr of H2O could still be recycled in the mantle at 2.8 Ga.Key PointsDeep water recycling might be possible even in early Earth conditions We provide a scaling law to estimate the amount of H2O flux deep into the mantle Subduction velocity has a a major control on the crustal dehydration pattern

show abstract

The 10Å phase: a high-pressure expandable sheet silicate stable during subduction of hydrated lithosphere

Cited by 105 publications

References 26 publications

In situ high-temperature Raman and FTIR spectroscopy of the phase transformation of lizardite

In situ high-temperature Raman and FTIR spectroscopy of the phase transformation of lizardite

The dehydroxylation of chrysotile: A combined in situ micro-Raman and micro-FTIR study

Deep water recycling through time

Contact Info

Product

Resources

About