Eocene sedimentation and volcanism in the Fig Lake Graben, southwestern British Columbia

1989 ◽  
Vol 26 (7) ◽  
pp. 1368-1373 ◽  
Author(s):  
Derek J. Thorkelson
Keyword(s):  
British Columbia ◽  
Shear Zone ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Fault System ◽  
Normal Faulting ◽  
Pull Apart Basin ◽  
Fault Block

The Fig Lake Graben is a narrow, complex Eocene basin that developed along part of the Coldwater fault system in southwestern British Columbia. Its origin as a pull-apart basin is probably related to dextral wrench faulting along the Fraser Fault and low-angle normal faulting of the Okanagan shear zone. Within the graben are Kamloops Group volcanic and sedimentary rocks, the thickness of which implies that one fault block has been downthrown at least 4.5 km. Geochemical interpretation of previously published analyses of Kamloops Group volcanic rocks indicates that magma production was genetically related to both extension and subduction.

Crustal velocity structure of the southern Nechako basin, British Columbia, from wide-angle seismic traveltime inversion1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.

2011 ◽  
Vol 48 (6) ◽  
pp. 1050-1063 ◽  
Author(s):  
A.L. Stephenson ◽  
G.D. Spence ◽  
K. Wang ◽  
J.A. Hole ◽  
K.C. Miller ◽  
...  
Keyword(s):  
British Columbia ◽  
Mountain Pine Beetle ◽  
Velocity Structure ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Velocity Model ◽  
Seismic Profile ◽  
Wide Angle ◽  
Seismic Velocities ◽  
Coast Mountains

In the BATHOLITHSonland seismic project, a refraction – wide-angle reflection survey was shot in 2009 across the Coast Mountains and Interior Plateau of central British Columbia. Part of the seismic profile crossed the Nechako Basin, a Jurassic–Cretaceous basin with potential for hydrocarbons within sedimentary strata that underlies widespread volcanic rocks. Along this 205 km-long line segment, eight large explosive shots were fired into 980 seismometers. Forward and inverse modelling of the traveltime data were conducted with two independent methods: ray-tracing based modelling of first and secondary arrivals, and a higher resolution wavefront-based first-arrival seismic tomography. Material with velocities less than 5.0 km/s is interpreted as sedimentary rocks of the Nechako Basin, while velocities from 5.0–6.0 km/s may correspond to interlayered sedimentary and volcanic rocks. The greatest thickness of sedimentary rocks in the basin is found in the central 110 km of the profile. Two sub-basins were identified in this region, with widths of 20–50 km and maximum sedimentary depths of 2.5 and 3.3 km. Such features are well-defined in the velocity model, since resolution tests indicate that features with widths greater than ∼13 km are reliable. Beneath the sedimentary rocks, seismic velocities increase more slowly with depth — from 6.0 km/s just below the basin to 6.3 km/s at ∼17 km in depth, and then to 6.8–7.0 km/s at the base of the crust. The Moho is found at a depth of 33.5–35 km beneath the profile, and mantle velocities are high at 8.05–8.10 km/s.

Tectonic significance of the Carboniferous Big Pond Basin, Cape Breton Island, Nova Scotia

1986 ◽  
Vol 23 (12) ◽  
pp. 2000-2011 ◽  
Author(s):  
Dwight C. Bradley ◽  
Lauren M. Bradley
Keyword(s):  
Sedimentary Rocks ◽  
Sedimentary Basins ◽  
Strike Slip ◽  
Fault System ◽  
Cape Breton Island ◽  
Cape Breton ◽  
Pull Apart Basin ◽  
Tectonic Significance ◽  
Basin Margin ◽  
Faulted Basin

Detailed mapping in southeastern Cape Breton Island has revealed a strike-slip origin for the small Carboniferous outlier at Big Pond. Topographically low Carboniferous sedimentary rocks occur between splays of a previously unrecognized, northeast-trending set of high-angle faults, the Big Pond fault system. The section is dominated by fanglomerates, which coarsen toward the faulted basin margins and which were deposited and (or) reworked by currents flowing toward the basin's center and along its axis. We interpret the fanglomerates as syntectonic. Interbedded limestones of Visean age (Windsor B Subzone) provide age control for the upper part of the 300 m section and, by inference, for at least some of the fault motion. Dextral motion on the Big Pond fault system is indicated by (1) slickenside stepping directions on minor faults, which juxtapose basement against basement and which parallel the main northeast-striking fault; (2) northeast-striking mesoscale faults within the basin, which produce dextral offsets; and (3) shear and extension fractures in fanglomerate clasts along the northeast-striking basin margin faults, which reveal dextral and down-to-basin motion. The location of the basin at a right step in the through-going dextral fault system implies that it is a pull-apart basin. We suggest that during Visean times, southern Cape Breton Island was cut by several such dextral wrench faults and associated sedimentary basins and that the tectonic climate was similar to that recognized by previous workers in Newfoundland and New Brunswick. No evidence was found in support of the paleomagnetically based hypothesis for sinistral strike slip during this time.

Provenance of Paleozoic sedimentary rocks in the Canadian Cordilleran miogeocline: a Nd isotopic study

1997 ◽  
Vol 34 (12) ◽  
pp. 1603-1618 ◽  
Author(s):  
Carmala N. Garzione ◽  
P. Jonathan Patchett ◽  
Gerald M. Ross ◽  
JoAnne Nelson
Keyword(s):  
British Columbia ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Canadian Shield ◽  
Isotopic Study ◽  
Middle Ordovician ◽  
Southern Alberta ◽  
T Values

Nd isotopes and trace elements in sedimentary rocks of the Yukon, the Northwest Territories, and northern British Columbia are used to examine the source of sediments in the Canadian Cordilleran miogeocline. Previous Nd isotope studies in southern Alberta demonstrated that strata of Neoproterozoic to Late Ordovician age were derived from Archean and Proterozoic Canadian Shield sources, whereas by the Late Devonian, a shift of 6 εNd units to younger crustal sources (εNd (T) = −6 to −9) had occurred. In this study, we found that the shift to younger crustal Nd isotopic signatures in the Yukon and Northwest Territories occurred much earlier than in southern Alberta. Cambrian and older strata have εNd(T) values of −10.0 to −21.1, consistent with derivation from Canadian Shield sources. Lower Ordovician through Permian strata in the Yukon and Northwest Territories, including the Innuitian-derived Imperial Assemblage, have εNd(T) values of −5 to −11.4. In northern British Columbia, the shift to a younger source reflects a wider range of εNd(T) values, from -−8.7 to −14.6 in Middle Ordovician through Middle Devonian strata, suggesting continued input from Canadian Shield sources. By the Middle Devonian, a complete shift to younger crustal signatures (εNd(T) = −5.9 to −10.5) had occurred in northern British Columbia. Several sources for the more juvenile sediments include (1) a mixture of locally erupted volcanic rocks with Canadian Shield sources, (2) a Grenville source, and (3) an Innuitian source. We propose that Ordovician to Lower Devonian strata were derived from a mixture of locally erupted, juvenile volcanics and pre-Cambrian Canadian Shield sources, and post-Middle Devonian strata were sourced from the Innuitian orogen in the Canadian Arctic.

The Hozameen fault system and related Coquihalla serpentine belt of southwestern British Columbia

1986 ◽  
Vol 23 (7) ◽  
pp. 1022-1041 ◽  
Author(s):  
G. E. Ray
Keyword(s):  
British Columbia ◽  
Sedimentary Rocks ◽  
Oceanic Island ◽  
Fault System ◽  
Ultramafic Rocks ◽  
Spreading Ridge ◽  
Early Triassic ◽  
Directed Movement ◽  
Serpentine Belt ◽  
Back Arc

The Hozameen Fault of southwestern British Columbia is associated with the Coquihalla serpentine belt and separates two distinct crustal units. Northeast of the fault are greenstones of the Early Triassic (?) Spider Peak Formation, which are unconformably overlain by Jurassic to Cretaceous turbidite and successor basin deposits of the Pasayten Trough. The oldest sedimentary rocks in the trough, the Ladner Group, contain a locally developed basal unit that hosts the Carolin mine gold orebody. Southwest of the fault, the Permian to Jurassic Hozameen Group represents a dismembered ophiolite succession comprising ultramafic rocks of the Petch Creek serpentine belt, overlain in turn by greenstone and chert units. The greenstones in the Hozameen Group and the Spider Peak Formation are geochemically distinguishable; the latter represent sodic, ocean-floor, subalkaline basalts formed in a spreading ridge environment, while the former include both arc tholeiites and oceanic island–seamount subalkaline basalts.Farther west, the major Petch Creek Fault separates the Hozameen Group from the Custer–Skagit Gneiss. This fault is locally associated with the Petch Creek serpentine belt and is considered to be a northern extension of the Ross Lake Fault of Washington State.The rocks in the Hozameen Group, Spider Peak Formation, and Pasayten Trough were probably deposited within a single basin that initiated as an extensive, multirifted, marginal back-arc basin and eventually evolved into the steadily narrowing Pasayten Trough.Following Early to Middle Cretaceous closure of the Pasayten Trough, oblique, easterly-directed movement along westerly-dipping thrusts caused the Custer–Skagit Gneiss to override the Hozameen Group, which in turn overrode rocks of the Pasayten Trough farther east; these boundary thrusts formed precursor structures for the Hozameen and Petch Creek faults. Ultramafic basement material underlying the Spider Peak Formation and the Hozameen Group was thrust up the bounding fractures, producing the Coquihalla and Petch Creek serpentine belts, respectively.Large-scale dextral transcurrent displacement, possibly related to movement along the Fraser Fault system, occurred subsequently along the Petch Creek and Hozameen faults. This wrench movement was preceded by the Mid-Eocene (?) intrusion of the Needle Peak pluton and was followed by emplacement of the 16–35 Ma Chilliwack batholith.

scholarly journals Interpretasi Vulkanostratigrafi Daerah Mamuju Berdasarkan Analisis Citra Landsat-8

EKSPLORIUM ◽  
2015 ◽  
Vol 36 (2) ◽  
pp. 71 ◽  
Author(s):  
Frederikus Dian Indrastomo ◽  
I Gde Sukadana ◽  
Asep Saepuloh ◽  
Agus Handoyo Harsolumakso ◽  
Dhatu Kamajati
Keyword(s):  
Pyroclastic Flow ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Landsat 8 ◽  
Geological Condition ◽  
Distribution Analysis ◽  
Visual Interpretation ◽  
Flow Paths ◽  
Fault Block ◽  
Basalt Composition

Daerah Mamuju dan sekitarnya umumnya disusun oleh batuan gunung api. Batuan sedimen vulkanoklastik dan batugamping berada di atas batuan gunung api. Aktivitas gunung api membentuk beberapa morfologi unik seperti kawah, kubah lava, dan jalur hembusan piroklastika sebagai produknya. Produk tersebut diidentifikasi berdasarkan karakter bentuk-bentuk melingkar di citra Landsat-8. Hasil koreksi geometrik dan atmosferik, interpretasi visual pada citra Landsat-8 dilakukan untuk mengidentifikasi struktur, geomorfologi, dan kondisi geologi daerah tersebut. Struktur geologi regional menunjukkan kecenderungan arah tenggara – baratlaut yang mempengaruhi pembentukan gunung api Adang. Geomorfologi daerah tersebut diklasifikasikan menjadi 16 satuan geomorfologi berdasarkan aspek genetisnya, yaitu punggungan blok sesar Sumare, punggungan kuesta Mamuju, kawah erupsi Adang, kawah erupsi Labuhan Ranau, kawah erupsi Sumare, kerucut gunung api Ampalas, kubah lava Adang, bukit intrusi Labuhan Ranau, punggungan aliran piroklastik Adang, punggungan aliran piroklastik Sumare, perbukitan sisa gunung api Adang, perbukitan sisa gunung api Malunda, perbukitan sisa gunung api Talaya, perbukitan karst Tapalang, dan dataran aluvial Mamuju, dataran teras terumbu Karampuang. Berdasarkan hasil interpretasi citra Landsat-8 dan konfirmasi lapangan, geologi daerah Mamuju dibagi menjadi batuan gunung api dan batuan sedimen. Batuan gunung api terbagi menjadi dua kelompok, yaitu Kompleks Talaya dan Kompleks Mamuju. Kompleks Talaya terdiri atas batuan gunung api Mambi, Malunda, dan Kalukku berkomposisi andesit, sementara Kompleks Mamuju terdiri atas batuan gunung api Botteng, Ahu, Tapalang, Adang, Ampalas, Sumare, dan Labuhan Ranau berkomposisi andesit sampai basal leusit. Vulkanostratigrafi daerah ini disusun berdasarkan analisis struktur, geomorfologi, dan distribusi litologi. Vulkanostratigrafi daerah Mamuju diklasifikasikan ke dalam Khuluk Talaya dan Khuluk Adang. Khuluk Talaya terdiri atas Gumuk Mambi, Gumuk Malunda, dan Gumuk Kalukku. Khuluk Mamuju terdiri atas Gumuk Botteng, Gumuk Ahu, Gumuk Tapalang, Gumuk Adang, Gumuk Ampalas, Gumuk Sumare, dan Gumuk Labuhan Ranau. Mamuju and its surrounding area are constructed mainly by volcanic rocks. Volcanoclastic sedimentary rocks and limestones are laid above the volcanic rocks. Volcanic activities create some unique morphologies such as craters, lava domes, and pyroclastic flow paths as their volcanic products. These products are identified from their circular features characters on Landsat-8 imagery. After geometric and atmospheric corrections had been done, a visual interpretation on Landsat-8 imagery was conducted to identify structure, geomorphology, and geological condition of the area. Regional geological structures show trend to southeast – northwest direction which is affects the formation of Adang volcano. Geomorphology of the area are classified into 16 geomorphology units based on their genetic aspects, i.e Sumare fault block ridge, Mamuju cuesta ridge, Adang eruption crater, Labuhan Ranau eruption crater, Sumare eruption crater, Ampalas volcanic cone, Adang lava dome, Labuhan Ranau intrusion hill, Adang pyroclastic flow ridge, Sumare pyroclastic flow ridge, Adang volcanic remnant hills, Malunda volcanic remnant hills, Talaya volcanic remnant hills, Tapalang karst hills, Mamuju alluvium plains, and Karampuang reef terrace plains. Based on the Landsat-8 imagery interpretation result and field confirmation, the geology of Mamuju area is divided into volcanic rocks and sedimentary rocks. There are two groups of volcanic rocks; Talaya complex and Mamuju complex. The Talaya complex consists of Mambi, Malunda, and Kalukku volcanic rocks with andesitic composition, while Mamuju complex consist of Botteng, Ahu, Tapalang, Adang, Ampalas, Sumare, danLabuhanRanau volcanic rocks with andesite to leucitic basalt composition. The volcanostratigraphy of Mamuju area was constructed based on its structure, geomorphology and lithology distribution analysis. Volcanostratigraphy of Mamuju area is classified into Khuluk Talaya and Khuluk Mamuju. The Khuluk Talaya consists of Gumuk Mambi, Gumuk Malunda, and Gumuk Kalukku, while Khuluk Mamuju consists of Gumuk Botteng, Gumuk Ahu, Gumuk Tapalang, Gumuk Adang, Gumuk Ampalas, Gumuk Sumare, and Gumuk Labuhan Ranau.

Revised stratigraphic nomenclature and age determinations for mid-Cretaceous volcanic rocks in southwestern British Columbia

1989 ◽  
Vol 26 (10) ◽  
pp. 2016-2031 ◽  
Author(s):  
Derek J. Thorkelson ◽  
Glenn E. Rouse
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Fault System ◽  
Volcanic Stratigraphy ◽  
Clastic Rocks ◽  
Lower Unit ◽  
Basement Rocks ◽  
Lithostratigraphic Units ◽  
Bridge Group ◽  
Stratigraphic Nomenclature

Mid-Cretaceous volcanic and volcaniclastic rocks in southwestern British Columbia, east of the Fraser Fault System, constitute two principal lithostratigraphic units. The lower unit, a composite succession of basaltic to rhyolitic lavas and various clastic rocks, is exposed in a 215 km linear belt from near Pavilion to south of Princeton. The upper unit, mostly amygdaloidal andesite, is restricted to the centre of the belt between Spences Bridge and Kingsvale, where it overlies the lower unit and contiguous basement rocks. Both units were deposited subaerially, concurrent with folding and faulting, and share a contact that varies from gradational, near Kingsvale, to unconformable, near Spences Bridge.The names "Spences Bridge Group" and "Kingsvale Group" were used by several authors for various parts of the volcanic stratigraphy. We suggest revision of nomenclature whereby the lower and upper units are named "Pimainus Formation" and "Spius Formation", respectively; together they constitute the Spences Bridge Group. The term "Kingsvale Group" is abandoned.Assemblages of fossil leaves and palynomorphs, collected from one Spius and seven Pimainus localities, include several species of early angiosperms. A late Albian age is thereby indicated for both formations; this is largely corroborated by isotopic dates from the volcanic strata and cross-cutting granitic plutons.

Distribution of Paleogene and Cretaceous rocks around the Nazko River belt of central British Columbia from 3-D long-offset first-arrival seismic tomography

2014 ◽  
Vol 51 (4) ◽  
pp. 358-372 ◽  
Author(s):  
Draga Talinga ◽  
Andrew J. Calvert
Keyword(s):  
British Columbia ◽  
Seismic Velocity ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Three Dimensional ◽  
Gravity Anomalies ◽  
Hydrocarbon Exploration ◽  
P Wave ◽  
Velocity Models ◽  
First Arrival

Across the Nechako–Chilcotin plateau of British Columbia, the distribution of Cretaceous sedimentary rocks, which are considered prospective for hydrocarbon exploration, is poorly known due to the surface cover of glacial deposits and Tertiary volcanic rocks. To constrain the subsurface distribution of these Cretaceous rocks, in 2008 Geoscience BC acquired seven long, up to 14.4 km, offset vibroseis seismic reflection lines across a north-northwest-trending belt of exhumed sedimentary rocks inferred to be part of the Taylor Creek Group. P-wave velocity models, which are consistent with sonic logs from nearby wells, have been estimated using three-dimensional first-arrival tomography to depths ranging from 1 to 4 km. Igneous basement can be identified on most lines using the 5.5 km/s isovelocity contour, which locates the top of the basement to an accuracy of ∼400 m where its depth is known in exploration wells. There is no general distinction on the basis of seismic velocity between Cretaceous sedimentary and Paleocene–Eocene volcanic–volcaniclastic rocks, both of which appear to be characterized in the tomographic models by velocities of 3.0–5.0 km/s. The geometry of the igneous basement inferred from the velocity models identifies north-trending basins and ridges, which correlate with exposed rocks of the Jurassic Hazelton Group. Identified Cretaceous sedimentary rocks occur beneath less negative Bouguer gravity anomalies, but the original distribution of these rocks has been disrupted by later Tertiary extension that created north-trending basins associated with the most negative gravity anomalies. We suggest that Cretaceous sedimentary rocks, if deposited, could be preserved within these basins if the rocks had not been eroded prior to Tertiary extension.

Mississippian volcanic assemblage conformably overlying Cordilleran miogeoclinal strata, Turnagain River area, northern British Columbia, is not part of an accreted terrane

2005 ◽  
Vol 42 (8) ◽  
pp. 1449-1465 ◽  
Author(s):  
Philippe Erdmer ◽  
Mitchell G Mihalynuk ◽  
Hubert Gabrielse ◽  
Larry M Heaman ◽  
Robert A Creaser
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Lower Paleozoic ◽  
Magmatic Arc ◽  
Structural Relationships ◽  
Geochemical Study ◽  
Tectonic Contact ◽  
Back Arc ◽  
T Values

A Paleozoic volcanic assemblage exposed in northern British Columbia, near the Turnagain River, previously considered to be part of an accreted terrane, was reported to be in depositional contact with a part of the Cordilleran miogeocline. This paper presents an integrated field, U–Pb geochronology, Sm–Nd isotopic, and geochemical study across the basal contact of the volcanic assemblage. Strongly evolved εNd(T) values, between –13 and –21, from samples of lower Paleozoic sedimentary rocks exposed below the volcanic rocks, and correlated with Atan – Kechika – Road River – Earn strata of the miogeocline farther east, support a North American miogeoclinal affinity, consistent with previously established regional stratigraphic and structural relationships. Nd isotopic data from the volcanic assemblage contrast significantly with data from the sedimentary rocks and record a mantle source (εNd(T) values between +4.0 and +7.0), consistent with a magmatic arc or back arc; negative Nb anomalies are similarly compatible with either arc- or back-arc-related magmatism. A concordant 339.7 ± 0.6 Ma U–Pb zircon date was obtained from the volcanic assemblage. The mixed gradational contact between the miogeoclinal and volcanic rocks is marked by interlayering of finely laminated grey and green phyllites on the scale of centimetres, with no evidence of a tectonic contact. Bedding at the contact is folded into tight outcrop-scale folds that are intruded by an Early Jurassic (187.5 ± 2.9 Ma) granodiorite. On the basis of all available evidence, the contact is interpreted as a facies transition. The Mississippian volcanic assemblage may link the miogeocline with the early development of an Angayucham – Slide Mountain basin.

Glacial Marine Sedimentation and Stratigraphy of the Toby Conglomerate (Upper Proterozoic), Southeastern British Columbia, Northwestern Idaho and Northeastern Washington

1971 ◽  
Vol 8 (7) ◽  
pp. 753-787 ◽  
Author(s):  
K. R. Aalto
Keyword(s):  
British Columbia ◽  
Regional Variation ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Ice Age ◽  
Late Precambrian ◽  
Upper Proterozoic ◽  
Marine Sedimentation ◽  
Grain Flow ◽  
New Interpretation

The outcrop of the Toby Conglomerate extends sinuously from southeastern British Columbia to northeastern Washington. It constitutes the basal part of the Windermere System (Upper Proterozoic), unconformably overlies the beveled Upper Purcell System, and conformably underlies either volcanic rocks or clastic Windermere sedimentary rocks of the Horsethief Creek Group and Monk Formation. The Toby Conglomerate consists chiefly of diamictite, which is complexly interstratified with conglomerates, sandstones, and argillites, the latter two containing dispersed megaclasts. Toby Conglomerate thickness ranges markedly from a few to nearly 2000 m. There is a dearth of tractive-current features within Toby sedimentary rocks. The presence of overlying pillow lavas and laminated argillites, turbidites, and grain flow deposits suggest that the basal Windermere System is of sub-aqueous origin. Paleogeographic reconstruction indicates deposition in the sea west of the orogenic landmass, Montania, peninsular to the Canadian Shield.Texture, composition, stratigraphie associations of Toby sedimentary rocks, and a lack of consistent regional variation suggest that the Toby Conglomerate was deposited by glacial marine sedimentation. Montania was overridden by ice traveling westward from the shield prior to Toby deposition. The basal Horsethief Creek Group and Monk Formation were produced largely by postglacial mass flow of slumped tills and deltaic deposits. This represents a new interpretation of the genesis of the Toby Conglomerate, one which accords with worldwide evidences of a Late Precambrian ice age.

Ore genesis at La Colorada Ag-Zn-Pb deposit in Zacatecas, Mexico

2004 ◽  
Vol 68 (6) ◽  
pp. 923-937 ◽  
Author(s):  
N. I. Chutas ◽  
R. O. Sack
Keyword(s):  
Solid Solution ◽  
Fluid Inclusion ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Strike Slip ◽  
Fault System ◽  
Ore Genesis ◽  
Fluid Inclusion Data ◽  
Native Silver

AbstractLa Colorada, in Zacatecas State, Mexico is an epithermal Ag-Zn-Pb system hosted in Mesozoic calcareous sedimentary rocks overlain by Tertiary volcanic rocks. The dominant vein is associated with a fault system that accommodates Tertiary normal and strike-slip faulting. The ore consists of fahlore [(Cu,Ag)10(Zn,Fe)2(Sb,As)4S13], polybasite [(Ag,Cu)16Sb2S11]–pearceite [(Ag,Cu)16As2S11] solid solution, pyrargyrite [Ag3SbS3]–proustite [Ag3AsS3] solid solution, acanthite-argentite [Ag2S], and native silver; associated sulphides include galena, sphalerite, chalcopyrite and pyrite. The Ag:Sb of the bulk concentrate from the mine is 1.076 and the Ag:Pb is 0.088. Compositions of the assemblages fahlore + pyrargyrite-proustite + sphalerite, and fahlore + polybasite-pearceite solid solution + (Ag,Cu)2S solid solution + sphalerite encapsulated in quartz and sphalerite indicate a primary depositional temperature of ∼325°C for a depth between 725 and 960 m below the inferred palaeosurface, which is in accord with fluid-inclusion data for higher elevations in the mine.

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