Petrologic and Minerochemical Trends of Acapulcoites, Winonaites and Lodranites: New Evidence from Image Analysis and EMPA Investigations
A comprehensive classification of primitive achondrites is difficult due to the high compositional and textural variability and the low number of samples available. Besides oxygen isotopic analysis, other minerochemical and textural parameters may provide a useful tool to solve taxonomic and genetic...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2015-07-01
|
| Series: | Geosciences |
| Subjects: | |
| Online Access: | http://www.mdpi.com/2076-3263/5/3/222 |
| _version_ | 1828223691357421568 |
|---|---|
| author | Vanni Moggi Cecchi Stefano Caporali |
| author_facet | Vanni Moggi Cecchi Stefano Caporali |
| author_sort | Vanni Moggi Cecchi |
| collection | DOAJ |
| description | A comprehensive classification of primitive achondrites is difficult due to the high compositional and textural variability and the low number of samples available. Besides oxygen isotopic analysis, other minerochemical and textural parameters may provide a useful tool to solve taxonomic and genetic problems related to these achondrites. The results of a detailed modal, textural and minerochemical analysis of a set of primitive achondrites are presented and compared with literature data. All the samples show an extremely variable modal composition among both silicate and opaque phases. A general trend of troilite depletion vs. silicate fraction enrichment has been observed, with differences among coarse-grained and fine-grained meteorites. In regard to the mineral chemistry, olivine shows marked differences between the acapulcoite-lodranite and winonaite groups, while a compositional equilibrium between matrix and chondrules for both groups, probably due to the scarce influence of metamorphic grade on this phase, was observed. The analysis of Cr and Mn in clinopyroxene revealed two separate clusters for the acapulcoite/lodranite and winonaite groups, while the analysis of the reduction state highlighted three separate clusters. An estimate of equilibrium temperatures for the acapulcoite-lodranite and winonaite groups is provided. Finally, proposals regarding the genetic processes of these groups are discussed. |
| first_indexed | 2024-04-12T17:11:02Z |
| format | Article |
| id | doaj.art-3a3d3a90b0fb4082aa90f2e059723972 |
| institution | Directory Open Access Journal |
| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-04-12T17:11:02Z |
| publishDate | 2015-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Geosciences |
| spelling | doaj.art-3a3d3a90b0fb4082aa90f2e0597239722022-12-22T03:23:47ZengMDPI AGGeosciences2076-32632015-07-015322224210.3390/geosciences5030222geosciences5030222Petrologic and Minerochemical Trends of Acapulcoites, Winonaites and Lodranites: New Evidence from Image Analysis and EMPA InvestigationsVanni Moggi Cecchi0Stefano Caporali1Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via La Pira 4, 50121 Florence, ItalyDipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, ItalyA comprehensive classification of primitive achondrites is difficult due to the high compositional and textural variability and the low number of samples available. Besides oxygen isotopic analysis, other minerochemical and textural parameters may provide a useful tool to solve taxonomic and genetic problems related to these achondrites. The results of a detailed modal, textural and minerochemical analysis of a set of primitive achondrites are presented and compared with literature data. All the samples show an extremely variable modal composition among both silicate and opaque phases. A general trend of troilite depletion vs. silicate fraction enrichment has been observed, with differences among coarse-grained and fine-grained meteorites. In regard to the mineral chemistry, olivine shows marked differences between the acapulcoite-lodranite and winonaite groups, while a compositional equilibrium between matrix and chondrules for both groups, probably due to the scarce influence of metamorphic grade on this phase, was observed. The analysis of Cr and Mn in clinopyroxene revealed two separate clusters for the acapulcoite/lodranite and winonaite groups, while the analysis of the reduction state highlighted three separate clusters. An estimate of equilibrium temperatures for the acapulcoite-lodranite and winonaite groups is provided. Finally, proposals regarding the genetic processes of these groups are discussed.http://www.mdpi.com/2076-3263/5/3/222primitive achondritesacapulcoitelodraniteswinonaitesX-ray maps |
| spellingShingle | Vanni Moggi Cecchi Stefano Caporali Petrologic and Minerochemical Trends of Acapulcoites, Winonaites and Lodranites: New Evidence from Image Analysis and EMPA Investigations Geosciences primitive achondrites acapulcoite lodranites winonaites X-ray maps |
| title | Petrologic and Minerochemical Trends of Acapulcoites, Winonaites and Lodranites: New Evidence from Image Analysis and EMPA Investigations |
| title_full | Petrologic and Minerochemical Trends of Acapulcoites, Winonaites and Lodranites: New Evidence from Image Analysis and EMPA Investigations |
| title_fullStr | Petrologic and Minerochemical Trends of Acapulcoites, Winonaites and Lodranites: New Evidence from Image Analysis and EMPA Investigations |
| title_full_unstemmed | Petrologic and Minerochemical Trends of Acapulcoites, Winonaites and Lodranites: New Evidence from Image Analysis and EMPA Investigations |
| title_short | Petrologic and Minerochemical Trends of Acapulcoites, Winonaites and Lodranites: New Evidence from Image Analysis and EMPA Investigations |
| title_sort | petrologic and minerochemical trends of acapulcoites winonaites and lodranites new evidence from image analysis and empa investigations |
| topic | primitive achondrites acapulcoite lodranites winonaites X-ray maps |
| url | http://www.mdpi.com/2076-3263/5/3/222 |
| work_keys_str_mv | AT vannimoggicecchi petrologicandminerochemicaltrendsofacapulcoiteswinonaitesandlodranitesnewevidencefromimageanalysisandempainvestigations AT stefanocaporali petrologicandminerochemicaltrendsofacapulcoiteswinonaitesandlodranitesnewevidencefromimageanalysisandempainvestigations |