Argilas da regi??o de Boa Vista - Roraima: mineralogia, geoqu??mica e aplica????o tecnol??gica

Autor: Riker, Silvio Roberto Lopes
Přispěvatelé: Horbe, Adriana Maria Coimbra
Jazyk: portugalština
Rok vydání: 2005
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UFAM
Universidade Federal do Amazonas (UFAM)
instacron:UFAM
Popis: Made available in DSpace on 2015-04-22T21:58:47Z (GMT). No. of bitstreams: 1 Silvio Roberto Riker.pdf: 15043307 bytes, checksum: 4d1386af66f898df11d59521db74eb19 (MD5) Previous issue date: 2005-04-20 The present dissertation reports the scientific studies on clays from the surroundings of Boa Vista, capital of Roraima State. The clay minerals found at Fazenda Santa Cec??lia are kaolinite, illite and swelling without identify which are associated to quartz, chlorite, goethite, muscovite, rutile, tourmaline, zircon, ilmenite, magnetite, monazite, calcite, plagioclase and fragments of ferruginous crust, granite, metachert, wacke, quartzite and carbonatic rock. Clay dominates over silt and sand. SiO2 and Al2O3 are the main oxides, followed by Fe2O3, K2O, TiO2 and MgO. Boron, Pb and As stand out followed by Ba, V, Y, Cr and Zn. Pollens ascending the deposits characterise two wet seasons intercalated by a drier season and ending with a dry/wet subactual climate. The 14C indicates that the onset of the clay deposits occurred 5.880 ?? 70 years B.P. The clay minerals found at Fazenda Brasil??ndia are kaolinite, illite and swelling without identify associated to quartz, chlorite, goethite, apatite, muscovite, rutile, sericite, zircon, carbonate, ilmenite, magnetite, garnet, plagioclase in addition to fragments of quartzite and ferruginous crust occurring in association. Sand dominates over clay and silt. SiO2 and Al2O3 predominate, followed by Fe2O3, TiO2 and K2O. Boron stands out, followed by V, Ba and Cr. Kaolinite and illite are the clay minerals found in the Boa Vista Formation, which are associated with quartz, apatite, muscovite, rutile, tourmaline, sericite, ilmenite, magnetite, zircon and fragments of metachert and ferruginous crust. Sand dominates over clay and silt. SiO2 and Al2O3 predominating, followed by Fe2O3, TiO2, K2O and Na2O, CaO and MgO are below the detection threshold. Boron stands out followed by V and Cr. Montmorillonite, kaolinite and illite are the clay minerals found on the sediments derived from the Apoteri Volcanic Complex with calcite, labradorite, chalcedony, quartz, rutile, ilmenite, magnetite and fragments of ferruginous crust occurring in association. Sand predominates over clay and silt, being that SiO2 and Al2O3 are dominant, followed by Fe2O3, CaO, MnO, MgO, TiO2, Na2O, K2O and Ba, Co and B stand out followed by V, Cr, Cu, Sr, Ni, Zn, Y and Sc. Kaolinite is the sole clay mineral present in the Quitaua?? river alluvium, and is associated with quartz, apatite, muscovite, ilmenite, zircon and ferruginous crust fragments. Clay is dominant over silt and sand. SiO2 and Al2O3 predominate over Fe2O3, TiO2, K2O, as well as B, Pb and As stand out followed by V, Zn, Cr and Y. Kaolinites on the studied region are badly crystallized and the oxi-hydroxide iron spots on the clays point out the activity of a new weathering cycle in the region. Technological tests certify the applicability of clays from Santa Cec??lia, Brasil??ndia and Quitaua?? river alluvium just for making by the industry of red ceramics. Nesta disserta????o s??o apresentados estudos cient??ficos efetuados em argilas ocorrentes em torno de Boa Vista, capital do Estado de Roraima. Caulinita, illita e expansivos n??o identificados s??o os argilominerais presentes na Fazenda Santa Cec??lia e encontram-se associados com quartzo, clorita, goethita, muscovita, rutilo, turmalina, zirc??o, ilmenita, magnetita, monazita, calcita, plagiocl??sio e fragmentos de crosta ferruginosa, granito, metachert, grauvaca, quartzito e rocha carbon??tica. Argila domina sobre silte e areia. SiO2 e Al2O3 predominam, seguidos de Fe2O3, K2O, TiO2 e MgO. Boro, Pb e As se destacam, seguidos de Ba, V, Y, Cr e Zn. P??lens caracterizam da base para o topo do dep??sito dois per??odos de clima ??mido, alternados por um per??odo mais seco e encerrando com um clima sub-atual seco/??mido. O 14C indica que o in??cio da deposi????o das argilas se deu a 5.880 ?? 70 anos A.P. Na Fazenda Brasil??ndia os argilominerais presentes s??o caulinita, illita e expansivos n??o identificados e em associa????o ocorrem quartzo, clorita, goethita, apatita, muscovita, rutilo, sericita, zirc??o, carbonato, ilmenita, magnetita, granada, plagiocl??sio al??m de fragmentos de quartzito e crosta ferruginosa. Areia domina sobre argila e silte. SiO2 e Al2O3 predominam, seguidos de Fe2O3, TiO2 e K2O. Boro se destaca, seguido de V, Ba e Cr. Caulinita e illita s??o os argilominerais presentes na Forma????o Boa Vista e est??o associados com quartzo, apatita, muscovita, rutilo, turmalina, sericita, ilmenita, magnetita, zirc??o e fragmentos de metachert e crosta ferruginosa. Areia domina sobre argila e silte. SiO2 e Al2O3 predominam, seguidos de Fe2O3, TiO2, K2O, e Na2O, CaO e MgO encontram-se abaixo do limite de detec????o. Boro se destaca, seguido de V e Cr. Montmorilonita, caulinita e illita s??o os argilominerais presentes nos sedimentos derivados do Complexo Vulc??nico Apoteri e em associa????o ocorrem calcita, labradorita, calced??nia, quartzo, rutilo, ilmenita, magnetita e fragmentos de crosta ferruginosa. Areia predomina sobre argila e silte, sendo que SiO2 e Al2O3 s??o dominantes, seguidos de Fe2O3, CaO, MnO, MgO, TiO2, Na2O, K2O e Ba, Co e B se destacam, seguidos de V, Cr, Cu, Sr, Ni, Zn, Y e Sc. Caulinita ?? o ??nico argilomineral na aluvi??o do rio Quitaua?? e est?? associada com quartzo, apatita, muscovita, ilmenita, zirc??o e fragmentos de crosta ferruginosa. Argila ?? dominante sobre silte e areia. SiO2 e Al2O3 predominam sobre Fe2O3, TiO2 e K2O e B, Pb e As se destacam, seguidos de V, Zn, Cr e Y. As caulinitas da regi??o estudada s??o mal cristalizadas e as manchas de ??xi-hidr??xido de ferro nas argilas indicam a atua????o de um novo ciclo intemp??rico na regi??o. Os testes tecnol??gicos atestam aplicabilidade das argilas de Santa Cec??lia, Brasil??ndia e da aluvi??o do rio Quitaua?? na ind??stria da cer??mica vermelha.
Databáze: OpenAIRE
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