Cathodoluminescence characteristics of Archean volcanogenic massive sulfide related quartz: Noranda, Ben Nevis and Matagami districts, Abitibi Subprovince, Canada

Abstract

[1] The cathodoluminescence (CL) of quartz from ore, stockwork, veins, and interstitial fillings between lava pillows from the $2.7 Ga Noranda, Ben Nevis and Matagami volcanogenic massive sulfide (VMS) districts, Abitibi greenstone belt, has been investigated using the ''hot cathode'' technique (HC1-LM system) to assess the potential of these various sample types to host primary, seafloor VMS-related fluids trapped as inclusions in minerals with primary depositional morphologies. The CL responses indicate that the various quartz types are of hydrothermal origin, and are therefore a potential host for primary hydrothermal fluid inclusions. Most notable is a transient (t < 120 s) blue CL, characteristic of hydrothermal quartz, observed in most samples. CL characteristics are similar over $250 km indicating coherent, nonrandom behavior. Furthermore, in ore and stockwork material from the Matagami and Noranda districts respectively, CL reveals primary concentric growth zoned quartz that predates pulses of sulfide deposition-clear evidence that the quartz is undeformed and directly related to VMS mineralization. These growth zones are not apparent in transmitted light. In addition, ore and stockwork quartz commonly show a very unstable (t < 30 s) yellow CL coincident with microfractures and grain boundaries, defining areas affected by secondary hydrothermal activity. In ore from Matagami, local zones of nontransient brown CL may reflect strain zones associated with the deformation and recrystallization of the massive sulfide mound and indicate that such modifications can be recognized and are minor in the investigated cases. CL clearly reveals pseudo-hexagonal, apparently zoned structures in sulfidemineralized breccia pipe quartz from the Ben Nevis area. These structures and their host quartz, characterized by a very unstable (t < 20 s) bright yellow CL, are interpreted as recrystallized quartz that has undergone rapid growth from a strongly supersaturated solution and noncrystalline precursor. The CL also clearly reveals colloform/crustiform textures indicative of open-space filling; these textures are not visible optically.

Feathery and network-like filamentous textures as indicators for the re-crystallization of quartz from a metastable silica precursor at the Rusey Fault Zone, Cornwall, UK

“…The Ti values, which are sometimes below the detection limit, indicate re-crystallization temperatures below 400 • C (Götte and Ramseyer, 2012). Relatively low re-crystallization temperatures (< 300 • C) are also confirmed by the presence of intense yellow CL along feathery texture subgrains and microcracks (Ioannou et al, 2004;Rusk et al, 2008). Though LA-ICP-MS analysis did not reveal essential differences in composition between observed quartz types, the obvious correlation in Al / Li and Si concentrations proves a different incorporation mechanism of respective elements that cannot be explained by varying P /T conditions, since both quartz types formed simultaneously.…”

Origin and significance of the yellow cathodoluminescence (CL) of quartz

“…In contrast to the luminescence behavior of quartz from magmatic, metamorphic, and sedimentary rocks, yellow CL (~580 nm) is uncommon and was up to now detected exclusively in some natural hydrothermal quartz as well as cryptocrystalline chalcedony and agate (Rink et al 1993;Götze et al 1999Götze et al , 2001a. There are a few reports from hydrothermal sulfide ore deposits (e.g., Moura et al 2003;Drechsel et al 2003;Ioannou et al 2003) and hydrothermal gold deposits (e.g., Graupner et al 2000;Takahashi et al 2008;Gueye et al 2013), where the yellow luminescent quartz was mostly detected in late mineralization sequences. In addition, quartz with yellow CL occurs in agate, silicified wood and hydrothermal veins related to mineralization and alteration processes in volcanic rocks (Götze et al 1999;Götze and Rössler 2000;Möckel and Götze 2007), as well as hydrothermal biomineralization (e.g., Müller et al 2009b).…”

“…In the ~2.7 Ga Archean volcanogenic massive sulfide (VMS) mineralization of the Abitibi Greenstone belt (Canada) quartz occurs associated with ore in stockwork, veins, and interstitial fillings between lava pillows (Ioannou et al 2003). Within the Noranda, Ben Nevis, and Matagami districts, short-lived yellow CL occurs in "late" secondary hydrothermal generation of ore and stockwork quartz that crosscuts an earlier generation and infills the primary breccia porosity (sample HQN, Fig.…”

“…1b). CL revealed colloform/crustiform textures suggesting rapid silica precipitation, commonly associated with open space deposition (Ioannou et al 2003).…”

Synvolcanic and Younger Plutonic Rocks from the Blake River Group: Implications for Regional Metallogenesis

“…Recently, fluid inclusion studies of quartz-and epidote-associated mineralization were undertaken by Ioannou et al (2004) and Weiershäuser and Spooner (2005). Their work illustrated that most of the quartz associated with mineralization was of low-temperature (110º-160ºC) hydrothermal origin with relatively low to moderate salinities, likely due to semiconformable alteration in a VMS environment.…”