Heterogeneous magmas of the Quaternary Sierra Chichinautzin volcanic fi eld (central Mexico): the role of an amphibole-bearing mantle and magmatic evolution processes
Fuente:
Redalyc
Guardado en:
| Autor principal: | |
|---|---|
| Formato: | Artículo científico |
| Lenguaje: | en |
| Publicado: |
Universidad Nacional Autónoma de México
2008
|
| Materias: | |
| Acceso en línea: | |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| _version_ | 1876483522285273088 |
|---|---|
| author | Lorenzo Meriggi |
| author_facet | Lorenzo Meriggi |
| contents | Heterogeneous magmas of the Quaternary Sierra Chichinautzin volcanic fi eld (central Mexico): the role of an amphibole-bearing mantle and magmatic evolution processes Lorenzo Meriggi José Luis Macías Simone Tommasini Lucia Capra Sandro Conticelli Ciencias de la Tierra high TiO 2 Trans Mexico Volcanic rocks The Quaternary Sierra Chichinautzin volcanic fi eld (SCVF) is located at the volcanic front of the Trans-Mexican Volcanic Belt (TMVB), ~350 km from the Middle American trench where the Cocos plate subducts beneath the North American plate. The SCVF is characterized by more than 200 monogenetic centers, ranging in composition from rare basalts to dacites. Less evolved terms have aphyric to porphyritic textures with phenocrysts of euhedral olivine (± Cr-spinels inclusions) + cpx, whereas evolved terms have porphyritic textures with phenocrysts of pyroxene (cpx>opx), xenocrysts of corroded quartz, and sieve-textured plagioclase from the local basement. Regardless of the degree of magmatic evolution, plagioclase occurs as microphenocrysts or in the groundmass. New geochemical and isotopic data presented in this work are in good agreement with previous analyses; however, a new division for the SCVF ma fi c rocks (MgO ≥ 6.0 wt.%) is proposed. In fact, although concentrations of large ion lithophile elements (LILE) and light to medium rare earth elements (REE) are roughly constant in ma fi c rocks, TiO 2 and other high fi eld strength elements (HFSE) such as Nb are scattered and vary from 0.8 to 1.8 wt.% and from 5 to 30 ppm, respectively. These characteristics allow grouping the SCVF rocks in two main magmatic series with different TiO 2 -HFSE enrichment: high(H)-TiO 2 and low(L)-TiO 2 , with subordinate transitional samples. Additionally, a cinder cone with shoshonitic af fi nity and extremely high LILE/HFSE ratio is reported for the fi rst time in central Mexico. Compositional variability is also observed among the mineral phases of these ma fi c rocks (e.g., the Cr# of spinel hosted in olivine phenocrysts), and the 87 Sr/ 86 Sr ratios that progressively increase from the H-TiO 2 series (0.70307–0.70425) to the L-TiO 2 series (0.70365–0.70434), up to the shoshonitic scoria (0.70456). The calc-alkaline af fi nity, LILE, and Pb positive anomalies of the magmas con fi rm the occurrence of a subduction-related metasomatised mantle wedge beneath the studied area (particularly for the shoshonitic scoria), but enrichments in TiO 2 and other HFSE are controversial. These enrichments are not common in subduction-related magmas because these elements are not easily removed by aqueous fl uids from the subducted slab. However, recent works have demonstrated that HFSE can be relatively soluble in high-temperature fl uids/melts arising from the slab, and the presence of TiO 2 -rich Cr-pargasite in lherzolite xenoliths of the Valle de Bravo area prove the existence of a mantle phase with high-HFSE concentrations. Therefore, partial melting of such hydrated peridotite could explain the genesis of H-TiO magmas as suggested by the proposed REE model. Moreover, isotopic ratios and variations in major and trace element concentrations of western SCVF rocks indicate that fractional crystallization plus crustal assimilation are the main evolution processes in the studied a 2008 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57230346001 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.2 Vol.25 |
| format | Artículo científico |
| id | redalyc_57230346001 |
| institution | Redalyc |
| language | en |
| publishDate | 2008 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | Heterogeneous magmas of the Quaternary Sierra Chichinautzin volcanic fi eld (central Mexico): the role of an amphibole-bearing mantle and magmatic evolution processes Lorenzo Meriggi Ciencias de la Tierra high TiO 2 Trans Mexico Volcanic rocks Heterogeneous magmas of the Quaternary Sierra Chichinautzin volcanic fi eld (central Mexico): the role of an amphibole-bearing mantle and magmatic evolution processes Lorenzo Meriggi José Luis Macías Simone Tommasini Lucia Capra Sandro Conticelli Ciencias de la Tierra high TiO 2 Trans Mexico Volcanic rocks The Quaternary Sierra Chichinautzin volcanic fi eld (SCVF) is located at the volcanic front of the Trans-Mexican Volcanic Belt (TMVB), ~350 km from the Middle American trench where the Cocos plate subducts beneath the North American plate. The SCVF is characterized by more than 200 monogenetic centers, ranging in composition from rare basalts to dacites. Less evolved terms have aphyric to porphyritic textures with phenocrysts of euhedral olivine (± Cr-spinels inclusions) + cpx, whereas evolved terms have porphyritic textures with phenocrysts of pyroxene (cpx>opx), xenocrysts of corroded quartz, and sieve-textured plagioclase from the local basement. Regardless of the degree of magmatic evolution, plagioclase occurs as microphenocrysts or in the groundmass. New geochemical and isotopic data presented in this work are in good agreement with previous analyses; however, a new division for the SCVF ma fi c rocks (MgO ≥ 6.0 wt.%) is proposed. In fact, although concentrations of large ion lithophile elements (LILE) and light to medium rare earth elements (REE) are roughly constant in ma fi c rocks, TiO 2 and other high fi eld strength elements (HFSE) such as Nb are scattered and vary from 0.8 to 1.8 wt.% and from 5 to 30 ppm, respectively. These characteristics allow grouping the SCVF rocks in two main magmatic series with different TiO 2 -HFSE enrichment: high(H)-TiO 2 and low(L)-TiO 2 , with subordinate transitional samples. Additionally, a cinder cone with shoshonitic af fi nity and extremely high LILE/HFSE ratio is reported for the fi rst time in central Mexico. Compositional variability is also observed among the mineral phases of these ma fi c rocks (e.g., the Cr# of spinel hosted in olivine phenocrysts), and the 87 Sr/ 86 Sr ratios that progressively increase from the H-TiO 2 series (0.70307–0.70425) to the L-TiO 2 series (0.70365–0.70434), up to the shoshonitic scoria (0.70456). The calc-alkaline af fi nity, LILE, and Pb positive anomalies of the magmas con fi rm the occurrence of a subduction-related metasomatised mantle wedge beneath the studied area (particularly for the shoshonitic scoria), but enrichments in TiO 2 and other HFSE are controversial. These enrichments are not common in subduction-related magmas because these elements are not easily removed by aqueous fl uids from the subducted slab. However, recent works have demonstrated that HFSE can be relatively soluble in high-temperature fl uids/melts arising from the slab, and the presence of TiO 2 -rich Cr-pargasite in lherzolite xenoliths of the Valle de Bravo area prove the existence of a mantle phase with high-HFSE concentrations. Therefore, partial melting of such hydrated peridotite could explain the genesis of H-TiO magmas as suggested by the proposed REE model. Moreover, isotopic ratios and variations in major and trace element concentrations of western SCVF rocks indicate that fractional crystallization plus crustal assimilation are the main evolution processes in the studied a 2008 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57230346001 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.2 Vol.25 |
| title | Heterogeneous magmas of the Quaternary Sierra Chichinautzin volcanic fi eld (central Mexico): the role of an amphibole-bearing mantle and magmatic evolution processes |
| topic | Ciencias de la Tierra high TiO 2 Trans Mexico Volcanic rocks |
| url | https://www.redalyc.org/articulo.oa?id=57230346001 |