eprintid: 10117706
rev_number: 14
eprint_status: archive
userid: 608
dir: disk0/10/11/77/06
datestamp: 2020-12-15 14:18:53
lastmod: 2021-09-26 23:23:33
status_changed: 2020-12-15 14:18:53
type: article
metadata_visibility: show
creators_name: Zappone, AS
creators_name: Benson, PM
title: Effect of phase transitions on seismic properties of metapelites: A new high-temperature laboratory calibration
ispublished: pub
divisions: UCL
divisions: B04
divisions: C06
divisions: F57
note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
abstract: We report new measurements of the seismic properties of an upper amphibolite facies metapelite from the Serie dei Laghi basement (southern Alps, northern Italy), presenting evidence for the α-β transition using elastic wave velocity methods and under in-situ conditions. Measurements were made using an internally heated gas apparatus under hydrostatic conditions to 500 MPa and temperatures to 1075 K. P-wave and S-wave velocities were measured parallel and normal to both lineation and foliation at room temperature. An average Vp (at 400 MPa) of 6.4 km/s and Vp anisotropy of 15% were found, and an average Vs1 of 3.6 km/s (8.2% anisotropy) and Vs2 of 3.5 km/s (4.1% anisotropy) were also measured. To observe the effects of the α-β quartz transition under hydrostatic conditions, elastic wave velocity was monitored continuously as the sample was heated to 1075 K. At 400 MPa, Vp was seen to decrease monotonically with increasing temperature to 950 K; as temperature continued to increase, Vp rapidly increased, until 1075 K. The effect was found to be reversible and is interpreted in terms of the α-β transition in quartz, in broad agreement with previous studies. A simple interpretation of the data, taking into account a field case from southern Tuscany as well as natural and elevated geothermal gradient, suggests that thermal and hydraulically driven fracture is a likely cause of “bright spots” seen in these areas. With knowledge of the depth of such features, the transition additionally allows the temperature at depth to be estimated.
date: 2013-04-01
date_type: published
publisher: GEOLOGICAL SOC AMER, INC
official_url: https://doi.org/10.1130/G33713.1
oa_status: green
full_text_type: other
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 1440646
doi: 10.1130/G33713.1
lyricists_name: Benson, Philip
lyricists_id: PMBEN89
actors_name: Jayawardana, Anusha
actors_id: AJAYA51
actors_role: owner
full_text_status: public
publication: Geology
volume: 41
number: 4
pagerange: 463-466
pages: 4
issn: 0091-7613
citation:        Zappone, AS;    Benson, PM;      (2013)    Effect of phase transitions on seismic properties of metapelites: A new high-temperature laboratory calibration.                   Geology , 41  (4)   pp. 463-466.    10.1130/G33713.1 <https://doi.org/10.1130/G33713.1>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10117706/1/Benson_G33713-Zappone%20v2%20accpt.pdf