Criteria for Recognit

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Recognition of Extension-Rifting Environments inAncient SuccessionsThe recognition of extensional rift environments and high-temperaturemagmatism in ancient successions is based on :1. Geological Evidence (stratigraphic - facies)2. Petrochemial EvidenceKey to area selection during regional or district -scale exploration
Recognition of Extension-Rifting Environments inAncient SuccessionsGeological CriteriaAncient rift successions have definitive geological characteristicsand a predictable stratigraphy related to extension, these include:1. A pre-rift succession that could be part of an oceanic, transitional orcontinental margin arc succession, followed by a bimodal rift successiondominated either by basalts or rhyolites, and in some deposit types(Bimodal-felsic and Siliciclastic-felsic) a post-rift ,thermal subsidencesuccession dominated by deep marine sedimentary rocks2. Evidence from volcanic and sedimentary facies of rapid subsidenceand restriction of lithofacies within fault blocks e.g. megabeccias - graben,cauldron, calderas3. Synvolcanic dike swarms and/or sill complexes4. High-level, comagmatic subvolcanic pluton comprised of sill-like intrusionsof tonalite, trondhjemite and gabbro whose composition matches that ofthe associated volcanic succession5. Pervasive zones of high-temperature, semiconformable alteration
Page 1 and 2: The Role of Extension and Rifting i
Page 3 and 4: OutlineExtension and Rifting - defi
Page 5 and 6: Extension and Rifting(McKenzie and
Page 7 and 8: Seafloor Hydrothermal Vents and Rel
Page 9 and 10: Examples from Modern Geodynamic Env
Page 11 and 12: Arc-frontVolcanoesBrothers VolcanoS
Page 13: Early Arc Rifting and Proto-Backarc
Page 18 and 19: The Manus Back-arc Basins (4 m.y. o
Page 20 and 21: Lau Back-Arc BasinNorthFijiLauSouth
Page 22 and 23: Lau BasinHawkins →general trendfr
Page 24 and 25: Distribution of Western Pacific Hyd
Page 26 and 27: Sibuet et al.,1998
Page 30 and 31: Altay-Sayan DistrictBathurst Distri
Page 32 and 33: Dikes in FlowsDikes in volcaniclast
Page 34 and 35: 1 st Generation2 nd Generation
Page 36 and 37: Basalt DikePillowFB BasaltDike
Page 38 and 39: PillowedBlockMega-Breccia - Evidenc
Page 40 and 41: Recognition of High-Temperature Sem
Page 42 and 43: .Subvolcanic Plutons
Page 44 and 45: Caldera Recognition• Multiphase,
Page 46 and 47: Recognition of Extension-Rifting En
Page 48 and 49: VMS- and Rift-Related Mafic Rocks
Page 50 and 51: Piercey and Gibson, 2005
Page 54 and 55: VMS- and Rift-Related FelsicRocks
Page 56 and 57: FI-FIV RhyolitesAfter Hart et al.,
Page 58 and 59: after Piercey and Gibson, 2005
Page 60 and 61: VMS- and Rift-Related FelsicRocks:

Criteria for Recognit

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