Published 1985 | Version v1
Miscellaneous Open

Magnetometry, radiometry and gammaspectrometry of the Janjao diatreme, Lages, State of Santa Catarina, Brazil

Creators

  • 1. Sao Paulo Univ. (Brazil). Inst. de Geociencias
  • 2. Engenharia de Minas, Industria, Comercio e Mineracao Haralyi Ltda, Sao Paulo (Brazil)
  • 3. Santa Catarina Univ., Florianopolis (Brazil)

Description

Magnetic, radiometric and gamma spectrometric surveys have been carried out on the Janjao diatreme which outcrops near Lajes in central-east Santa Catarina State, Brazil. The body is deeply weathered on the surface and its concentrates contain serpentinized olivine, phlogopote, pyroxenes, ilmenites, garnet and zircon. The interpretation of the magnetic anomaly revealed an irregular diatreme whose main dimensions are 50 X 190 meters. A vertical to subvertical dyke cuts the main diatreme. The radiometric anomaly as well as the potassium content helped to delineate the contacts between the diatreme and its country rocks (sandstones). Faults striking NNE controlled the emplacement of the Janjao diatreme as well as the intrusion of an alkaline dyke located near the diatreme. (Author)

Availability note (English)

MF available from INIS under the Report Number.

Abstract (Portuguese)

Levantamentos magneticos, radiometricos e gamaespectrometricos foram reliazados no diatrema Janjao que aflora nas proximidades de Lages na regiao centro-leste do estado de Santa Catarina. O corpo apresenta um nivel de intemperismo, acelerado na superficie e seus concentrados contem olivina serpentinizada, flogopita, piroxenios, ilmenitas, granada e zircao. A interpretacao da anomalia magnetica revelou um diatrema irregular com dimensoes de 50 X 190 metros. Um dique vertical a subvertical atravessa o diatrema principal. A anomalia radiometrica assim como o conteudo potassico auxiliaram na demarcacao dos contatos entre o diatrema e a rocha encaixante (arenitos). Falhas com direcao estrutural NNE controlaram a colocao do diatrema Janjao assim como a intrusao de um dique alcalino localizado nas proximidades do diatrema. (D.J.M.)

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Additional details

Additional titles

Original title (Portuguese)
Magnetometria, radiometria e gamaespectrometria na diatrema Janjao, Lages, SC

Publishing Information

Imprint Pagination
12 p.
Report number
INIS-BR--564

Conference

Title
2. Geology South Brazilian Symposium.
Dates
Oct 1985.
Place
Florianopolis, SC (Brazil).

INIS

Country of Publication
Brazil
Country of Input or Organization
Brazil
INIS RN
18001739
Subject category
S58: GEOSCIENCES;
Resource subtype / Literary indicator
Conference
Descriptors DEI
BRAZIL; GAMMA SPECTROSCOPY; KIMBERLITES; MAGNETIC SURVEYS; POTASSIUM; RADIOMETRIC SURVEYS
Descriptors DEC
ALKALI METALS; DEVELOPING COUNTRIES; ELEMENTS; GEOLOGIC SURVEYS; GEOPHYSICAL SURVEYS; IGNEOUS ROCKS; LATIN AMERICA; METALS; PERIDOTITES; PLUTONIC ROCKS; ROCKS; SOUTH AMERICA; SPECTROSCOPY