IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

1P1_1E-O16

Room A3

Date/Time: July 21 15:15-15:30

Understanding the volcanic processes, stratigraphy and mineralization of the archeanteutonic bore, jaguar and bentley volcanic massive sulphide deposits, yilgarn craton,western australia.
Ritipurna Das1 , Ray Cas1 , Patrick Hayman1 , James Bell2 , Steve Lynn2 , Paull Parker2
1

Monash University, Australia, 2 Independence Group NL, Australia
E-mail: ritipurna.das@monash.edu.au

Teutonic Bore, Jaguar and Bentley volcanic hosted massive sulphide deposits are situated in the Eastern
Goldfields of the Archean Yilgarn Craton, Western Australia. The VMS complex is situated in the Gindalbie Terrane
which is a linear belt (2695-2680 Ma). This bimodal rhyolite-basalt volcanic belt enriched in high field strengthelements, consists of felsic calc-alkaline volcanic rocks, quartz rich sedimentary rocks, layered mafic complexes
and mafic sills, formed during a period of regional extension in a back arc setting. The VMS deposits are hosted
by a bimodal mafic and felsic volcanic succession with associated volcaniclastics and mudstones, and are locatedalong strike over a 12 km distance. The rocks are metamorphosed to lower greenschist facies and have undergone
moderate deformation.

The stratigraphy is divided into a hanging wall facies association and a footwall facies association, which
are commonly separated by sulphide mineralization.

The dominant lithofacies are coherent basalt, rhyolite,

andesite and dolerite, which form concordant, tabular bodies black mudstone, with minor graded bedded
sandstones (turbidites) and rare polymictic conglomerates, represent the ambient deep water facies that areintercalated with the volcanic units. The basalt is present in both the hanging wall and footwall and contains both
massive and pillow basalt facies, indicating that at least some basalts were seafloor lavas. However, monomictic
volcanic breccia, commonly with peperitic textures, occurs at the tops and bottoms of many basalt units, indicatingthat they intruded into unconsolidated sediments. The rhyolite is mainly present in the footwall and is highly altered.
Dolerite occurs as late intrusions with coarse crystalline textures.

The Teutonic Bore consists of one steeply dipping lens of massive polymetallic sulphide underlain by stringer
mineralization. The Jaguar and Bentley deposit consists of three lenses of massive sulphide that are split by alate dolerite intrusion. The massive sulphide consists of pyrite, sphalerite and chalcopyrite. The mineralization ismainly hosted by black mudstone but also occurs in pillowed basalt above the rhyolites. The sulphide lens occurs
as: 1. massive bodies without any dominant fabric; 2. banded bodies of pyrite and sphalerite and chalcopyrite
replacing the pyrite at places; and 3. stringer and disseminated patches. The sulphide shows replacement textureswith basalt and black mudstone, and therefore represents sub-seafloor mineralization that postdates sedimentation
and basalt emplacement. The disseminated sulphide occurs both in the hanging wall and footwall as patches andblebs. Hydrothermal alteration extends into the hanging wall, which also supports a late mineralizing event.

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