The Lake Ambrose volcanic belt (LAVB) outcrops as a 45 km long northeast-trending belt of mafic and felsic volcanic rocks along the eastern side of the Victoria Lake Group in southcentral Newfoundland. It comprises roughly equal proportions of mafic pillow basalt and high silica rhyolite, locally interbedded with epiclastic turbidites. Volcanic rocks have been metamorphosed in the greenschist facies and are extensively carbonatized.U-Pb (zircon) dates from rhyolite at two, widely separated localities give identical ages of 513 + 2 Ma (Upper Cambrian), and this is interpreted as the eruptive age of the volcanic sequence. Primitive arc and low-K tholeiites can be recognized on the basis of major and trace element geochemistry, ranging from LREE-depleted to LREE-enriched. Geochemical variation between mafic volcanic types is interpreted predominantly to reflect contrasts in source characteristics and degree of partial melting; some variation within each geochemical type attributable to fractional crystallization can be recognized. Detailed examination of some samples indicates that the heavy REE and related elements have locally been mobile, probably as a result of carbonate complexing.The LAVB is the oldest well-dated island arc sequence in Newfoundland, and perhaps in the Appalachian-Caledonian Orogen. Its age requires modification of widely held models for the tectonic history of central Newfoundland. It is older than the oldest known ophiolite, demonstrating that arc volcanism was extant before the generation of the oldest known oceanic crust in this part of Iapetus. It further demonstrates that there was a maximum of approximately 30 Ma between the rift-drift transition which initiated Iapetus, and the initiation^ of subduction. This suggests that the oceanic sequences preserved in Newfoundland represent a series of arcs and back arc basins marginal to the main Iapetus Ocean, and brings into question whether the Appalachian accreted terranes contain any remnants of normal mid-ocean ridge type Iapetan crust.

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The structurally controlled central Newfoundland gold belt is emerging as one of the next significant mining jurisdictions in Canada. Gold mineralization is associated with crustal-scale faults that preserve synorogenic conglomerates, similar to the setting of orogenic gold in the Archean Abitibi greenstone belt. Recent exploration in the Wilding Lake region exposed a system of auriferous quartz veins hosted within sedimentary and volcanic rocks. Detailed lithological and structural documentation of these newly exposed zones was conducted to examine controls on gold mineralization and place the vein system into a regional context. Field data demonstrate that the main 'Elm' quartz vein extends for approximately 230 m along strike, is up to 2 m wide and cuts the conglomerate host within an oblique sinistral shear zone that accommodated north-northeast-directed thrusting. An early set of moderately dipping extensional quartz veins, consistent with oblique sinistral shear, emanate from the main vein. A later, more steeply dipping set of extensional quartz veins crosscut the main vein and the earlier vein set, and are consistent with a component of horizontal extension. Chalcopyrite and malachite occur locally in the early vein set, but are more abundant overall within the younger vein set. A nearly conjugate set of steeply dipping extension fractures crosscut the main vein and the two vein sets. These fractures are filled typically with vuggy quartz and unaltered and altered sulphides. Field data are consistent with progressive deformation characterized by early oblique compressional sinistral shear and subsequent components of subhorizontal extension and minor dextral strike-slip.

The formation and preservation of orogenic gold deposits are associated with a predictable set of magmatic, structural, and tectonic processes that have recurred throughout Earth's history. In world-class Archean gold districts, such as in the Superior Province of the Canadian Shield and the Yilgarn Craton of the West Australian Shield, the main gold-mineralized fault zones are characterized by early imbrication, lithospheric extension, synorogenic magmatism and sedimentation, thick-skinned re-imbrication, and late-stage strike-slip. Such an evolution results in the occurrence of gold-mineralized, upper crustal sequences of synorogenic magmatic and sedimentary rocks above terranes of granitoid rocks and/or older poly-deformed volcanic rocks. Targeted exploration for orogenic gold mineralization relies on remnant panels of synorogenic rocks (e.g. polymict conglomerate and bimodal magmatic rocks) as first-order field indicators of structurally controlled gold preservation along prospective crustal-scale fault zones. Paleozoic crustal-scale fault zones in central Newfoundland have been known to host significant gold mineralization and recent major discoveries (e.g. Valentine Lake gold deposit) and associated exploration suggest the emergence of a new district centred on the footwall rocks of the Victoria Lake shear zone. Fieldwork, combined with structural analysis and high-precision U-Pb geochronology throughout central Newfoundland, demonstrates that the structurally controlled Paleozoic gold district is remarkably similar to the much older Archean Abitibi gold district in scale, geological setting, structural architecture, synorogenic magmatism and sedimentation, style of mineralization, tectonic evolution, and process rates. In central Newfoundland, orogenic gold occurs within footwall blocks of an overall northwest-directed fault system that juxtaposed and deformed Neoproterozoic basement granitoid rocks and Late Silurian to Early Devonian synorogenic rocks during the Acadian Orogeny. Preliminary high-precision U-Pb zircon and rutile geochronology demonstrates that the key tectonic interval driving gold mineralization and synorogenic sedimentation and magmatism, including syenogranite and monzonite intrusions, occurred between 424 and 407 Ma, approximately the same relative time interval (15-20 million years) as the Abitibi greenstone belt. The similarities between the gold systems of central Newfoundland and the Abitibi imply that a common predictable set of structural and tectonic processes throughout Earth's history, and thus independent of time, have led to the deposition and preservation of orogenic gold mineralization.

Crustal-scale fault zones in central Newfoundland are being recognized as significant gold-mineralized structures. In particular, a northeast-trending structural corridor in the eastern Dunnage Zone (Exploits subzone), delineated by the Rogerson Lake Conglomerate, contains highly prospective vein-hosted gold deposits. Such mineralized vein systems, exposed near Valentine Lake (Marathon Gold Corp.) and Wilding Lake (Antler Gold Inc.), are products of progressive Paleozoic deformation and fluid-pressure cycling along crustal-scale faults that cut the Late Silurian to Early Devonian Rogerson Lake Conglomerate and underlying Neoproterozoic basement rocks. Well exposed, gold-bearing quartz-vein systems in the Wilding Lake area reveal a kinematic history that involved a main phase of reverse sinistral shearing and subsequent transient phases of horizontal extension, oblique compression, and, at least locally, components of late dextral strike-slip. High-grade gold mineralization is associated with siderite-ankerite-sericite alteration of the host rocks, structurally controlled quartz-vein emplacement, and supergene alteration of pyrite and chalcopyrite. Gold-bearing vein sets contain quartz, pyrite, chalcopyrite, tourmaline, native gold, Ag-poor electrum, bismuth-silver-gold tellurides, rutile, and secondary goethite, malachite, and acanthite. Prospective gold exploration targets in the Wilding Lake area are Late Silurian feldspar porphyry and felsic volcanic rocks overlying the Rogerson Lake Conglomerate, as well as, rheologically favourable Neoproterozoic basement granitoids that may provide a setting similar to that at Valentine Lake.