000 02923naaaa2200301uu 4500
001 https://directory.doabooks.org/handle/20.500.12854/70307
020 _aintechopen.71674
024 7 _a10.5772/intechopen.71674
_cdoi
041 0 _aEnglish
042 _adc
072 7 _aPNV
_2bicssc
100 1 _aFoucaud, Yann
_4auth
700 1 _aFilippov, Lev
_4auth
700 1 _aLechenard, Bénédicte
_4auth
700 1 _aMarion, Philippe
_4auth
245 1 0 _aChapter Geology, Textural Study, Ore Genesis and Processing of the Tabuaço Tungsten Deposit (Northern Portugal)
260 _bInTechOpen
_c2018
506 0 _aOpen Access
_2star
_fUnrestricted online access
520 _aThe Tabuaço tungsten deposit (Northern Portugal) is hosted in the Cambrian Douro Group metasediments, at the northern margin of the Beira-Tabuaço granitic complex. The hosting schisto-calcareous Lower Cambrian Bateiras Formation underwent a contact metamorphism induced by the intrusion of the granitic complex. The skarnification led to the crystallisation of scheelite (CaWO4). Two different skarn facies are encountered: ‘Lower Skarn’ and ‘Main Skarn’ both corresponding to the exoskarn. The ‘Main Skarn’ is mainly composed of vesuvianite (Ca10Mg2Al4(SiO4)5(Si2O7)2(OH)4), feldspars and fluorite. Zoisite, grossular, fluorapatite and scheelite are also present, as well as malayaite and cassiterite. Scheelite is disseminated and often occurs in association with fluorite, albite and vesuvianite. The ‘Lower Skarn’ level contains predominantly diopsidic pyroxene, quartz, zoisite, grossular and feldspars. Scheelite appears both laminated and disseminated, in association with fluorite and vesuvianite in minor proportions. The ‘Main Skarn’ is located in the Garnet, Pyroxene zone, while the ‘Lower Skarn’ corresponds to the Pyroxene, Garnet zone. Pyroxene has a global hedenbergite Hd40 composition. A major phase of albitisation destabilised fluorite, scheelite, vesuvianite, garnet and pyroxene. A late stage of chloritisation is associated with the exhumation. The processing of the Tabuaço ore has been adapted to the Ca-bearing rich paragenesis and to the scheelite mean size.
540 _aCreative Commons
_fhttps://creativecommons.org/licenses/by/3.0/
_2cc
_4https://creativecommons.org/licenses/by/3.0/
546 _aEnglish
650 7 _aMineralogy & gems
_2bicssc
653 _askarn, scheelite, texture, paragenesis, processing
773 1 0 _0OAPEN Library ID: ONIX_20210602_10.5772/intechopen.71674_387
_7nnaa
856 4 0 _awww.oapen.org
_uhttps://library.oapen.org/bitstream/20.500.12657/49273/1/57812.pdf
_70
_zDOAB: download the publication
856 4 0 _awww.oapen.org
_uhttps://library.oapen.org/bitstream/20.500.12657/49273/1/57812.pdf
_70
_zDOAB: download the publication
856 4 0 _awww.oapen.org
_uhttps://directory.doabooks.org/handle/20.500.12854/70307
_70
_zDOAB: description of the publication
999 _c38227
_d38227