Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/7777
DC Field | Value | Language |
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dc.contributor.authorall | Iezzi, G.; Università degli studi G. D'annunzio, Chieti Pescara, Italy | en |
dc.contributor.authorall | Tribaudino, M.; Università degli studi di Parma, Parma, Italy | en |
dc.contributor.authorall | Ventura, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia | en |
dc.contributor.authorall | Margiolaki, I. | en |
dc.date.accessioned | 2012-02-22T11:39:45Z | en |
dc.date.available | 2012-02-22T11:39:45Z | en |
dc.date.issued | 2011 | en |
dc.identifier.uri | http://hdl.handle.net/2122/7777 | en |
dc.description.abstract | The thermal behavior of three amphiboles along the join “Mg-richterite” [MRIC: ANaB(NaMg) CMg5TSi8O22W(OH)2]–richterite [RIC: ANaB(NaCa)CMg5TSi8O22W(OH)2] was investigated by in situ synchrotron radiation powder diffraction between 90 and 873 K. The studied samples have B-site compositions Na1Mg1 (sample RN1), Na0.97Mg0.8Ca0.24 (sample RN2), and Na0.97 Mg0.58Ca0.45 (sample RN6). The evolution of cell parameters as a function of T shows a discontinuity in the two Mg-richer samples (RN1 and RN2), which is interpreted as evidence of a P21/m → C2/m phase transition, whereas the Ca-richer sample (RN6) shows no evidence of a phase transition. The transition in samples RN1 and RN2 follows a different thermodynamic behavior, being tricritical in end-member “Mg-richterite” (RN1) and second order in the BCa-bearing amphibole RN2. A thermodynamic analysis done according to the Landau formalism and allowing for order parameter saturation, gives Tc = 462(3) and 378(1) K, and saturation temperature 𝛉s =116(21) and 141(7) for RN1 and RN2, respectively. Comparison with data from literature shows that the thermal strain of C-centered amphiboles with constant A-, C-, T-, and W-site occupancy equal to Na, Mg5, Si8, and (OH)2, respectively, and a B-site occupied by variable amounts of Li, Na, Mg, and/or Ca, mainly expands about 70° from c toward the a cell-edge onto the 010 plane. Conversely, the spontaneous strain accompanying the thermal transition shows that the maximum expansion is oriented about 25° from c and is coupled with a contraction close to the a cell direction. On the other side, transition induced by solid solution at room-T follows an almost opposite deformation pattern. The present data confirm the hypothesis of a first-order character of the transition induced by the increase of the B-site dimension for increasing BCa contents, similarly to the closely related P21/c → C2/c transition in pyroxenes. | en |
dc.language.iso | English | en |
dc.relation.ispartof | American Mineralogist | en |
dc.relation.ispartofseries | 2-3/96(2011) | en |
dc.subject | Synthetic amphibole | en |
dc.subject | phase transition | en |
dc.title | The high-temperature P21/m -> C2/m phase transitions in synthetic amphiboles along the richterite-(BMg)-richterite join | en |
dc.type | article | en |
dc.description.status | Published | en |
dc.type.QualityControl | Peer-reviewed | en |
dc.description.pagenumber | 353-363 | en |
dc.subject.INGV | 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics | en |
dc.identifier.doi | 10.2138/am.2011.3559 | en |
dc.description.journalType | JCR Journal | en |
dc.description.fulltext | restricted | en |
dc.contributor.author | Iezzi, G. | en |
dc.contributor.author | Tribaudino, M. | en |
dc.contributor.author | Ventura, G. | en |
dc.contributor.author | Margiolaki, I. | en |
dc.contributor.department | Università degli studi G. D'annunzio, Chieti Pescara, Italy | en |
dc.contributor.department | Università degli studi di Parma, Parma, Italy | en |
dc.contributor.department | Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia | en |
item.openairetype | article | - |
item.cerifentitytype | Publications | - |
item.languageiso639-1 | en | - |
item.grantfulltext | restricted | - |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
item.fulltext | With Fulltext | - |
crisitem.author.dept | Università degli studi G. D'annunzio, Chieti Pescara, Italy | - |
crisitem.author.dept | Dipartimento di Scienze della Terra, Università di Parma, Parma, Italy | - |
crisitem.author.dept | Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione Roma1, Roma, Italia | - |
crisitem.author.dept | European Synchrotron Radiation Facility (ESRF),Grenoble, France | - |
crisitem.author.orcid | 0000-0001-9388-9985 | - |
crisitem.author.parentorg | Istituto Nazionale di Geofisica e Vulcanologia | - |
crisitem.classification.parent | 04. Solid Earth | - |
crisitem.department.parentorg | Istituto Nazionale di Geofisica e Vulcanologia | - |
Appears in Collections: | Article published / in press |
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