Description

Location: Reno Aces, Greater Nevada Field Upstairs

Contact: gsn@gsnv.org

Guest Speaker: Gabe Aliaga, Geologist, Ridgeline Minerals

 Title“From deep porphyry to shallow oxide and everything in between: A holistic approach to mineral exploration at the Selena project, White Pine County, Nevada”

 Date:   FRIDAY, FEBRUARY 18, 2022

 Time:  Drinks @ 6 pm, Dinner @ 6:30 pm, Talk @ 7:15 pm

 WhereReno Aces Ball Park, 250 Evans St.

Upstairs at the 250 Lounge/Good Hops Restaurant

Abstract:

The Selena property is a shallow-oxide, silver-gold-lead-zinc discovery made by Ridgeline Minerals in 2020. The project is located within the historic Limousine Butte district of the south Carlin-Trend with the claim block comprised of 467 contiguous federal lode claims totaling 39km². Historic and currently producing mines in the area include the Bald Mountain, Alligator Ridge, Yankee, Illipah and Golden Butte deposits. Preliminary trenching followed by four phases of drilling have defined a mineralized footprint that begins at surface and extends 1.3km E-W and over 2.0 km N-S with mineralization open in multiple directions. Follow-up drilling in 2021 confirmed the shallow oxide potential of the system while also intersecting higher-grade silver-lead-zinc zones at depth. The style of mineralization and proximity to a known copper-gold porphyry system located ~1km to the west of the property suggests the Au-Ag mineralization represents the outer halo of a zoned hydrothermal system, with potential to discover a previously unrecognized Carbonate Replacement (CRD) style deposit under relatively shallow cover.

Ordovician through Pennsylvanian rocks crop out in the southern Cherry Creek Range and dip 20-30° to the west. Hosts for replacement-style mineralization include the Devonian Guilmette Limestone and the contact between Mississippian Joana Limestone and overlying Chainman Shale. Folds and thrusts with approximately N-S strikes are recognized in geologic mapping and in drilling; silicified outcrops are largely controlled by thrusts. Other important controls include younger, NE-striking faults showing the most offset and older, WNW faults showing less offset but appearing to control high-grade replacement mineralization.

Undated quartz-feldspar porphyry intrusions crop out at the intersections of thrusts and west-northwest faults. Geometries of these intrusions appear to be irregular, discontinuous dikes and small plugs. Drilling thus far indicates the intrusions themselves do not carry grade, however they are spatially associated with mineralization and typically oxidized and argillized. Volcanic rocks 8 km north of the property give Eocene K-Ar ages and the Cherry Creek pluton 12 km to the northeast, along with its associated polymetallic mineralization, are also dated as Eocene. Intrusions at Selena are presumably Eocene, however the Butte Valley porphyry, adjacent to the property to the west, has a reported Cretaceous U-Pb zircon age of 98.5 Ma. The timing is similar to the Cretaceous copper porphyry of the Robinson Mining District 60 km south of Selena.

Further investigation may find overprinting magmatism and/or mineralization, but a zonation in metals has been demonstrated by Ridgeline at Selena. Prospects east and north of the defined mineralized footprint show a greater Au/Ag ratio. Drilling to the west in 2021 targeted the mineralization at depth and showed increased Ag, Pb, and Zn across all drillholes. Highlight intercepts from the 2021 program include 4.6m grading 421 g/t Ag, 0.6 g/t Au, 4.4% Pb and 3.7% starting at 191m true vertical depth (TVD) in SE21-024, and 44.2m grading 123.2 g/t Ag, 0.1 g/t Au, 1.5% Pb and 0.6% Zn starting at 232m TVD in SE21-025.

Decarbonatization, silicification, and brecciation of carbonate rocks characterize alteration at Selena. Contacts between altered and unaltered rock are sharp and parallel to controlling faults and bedding. Banded calcite veins often bound zones of mineralization and can be involved in silicified breccias. Hydrothermal dolomitization occurs in some areas as margins to mineralized zones. Argentiferous manganese oxide mineralization (AMOM) occurs in most zones and can continue as veinlets into surrounding unaltered rock. All intercepts drilled by Ridgeline thus far are oxidized and hematite-rich, but the western-most hole demonstrated a significant increase in sulfide content as well as the first instance of unoxidized intrusions on the property. Vectoring towards the buried copper porphyry to target sulfide (CRD) replacement mineralization is Ridgeline’s primary exploration focus in 2022 with a 5,500m drill program planned for mid-April.

Gabe Aliaga Bio:
Gabriel Aliaga was born and raised in Chicago to Bolivian immigrants and completed his B.S. in Earth & Environmental Sciences at the University of Illinois at Chicago. After working three years in a hospital analytical lab, he desperately missed the rocks, and was convinced by his then-girlfriend, now-wife to apply to graduate school. Gabe moved out west and completed his M.S. in Geology at the University of Nevada, Reno, in 2018. His thesis under Dr. Mike Ressel characterized and age-dated the igneous rocks and associated alteration of the Keystone window in the Simpson Park Mountains of north-central Nevada, adding to the importance of the Eocene epoch to Nevada’s gold endowment. After graduating, he worked for Nevada Exploration Inc. and helped advance the South Grass Valley project. Gabe is now with Ridgeline Minerals Inc. and busy merging boots-on-the-ground field work, 3D modeling, and drill targeting into an exciting adventure looking for the next big one. He lives in Sparks, NV, with his wife Naseem, dog Terra, and two cats, Astra and Luna.

 


Details

02/18/2022 18:00:0002/18/2022 21:00:00America/Los_AngelesGSN Regular Membership Meeting, Reno, NevadaGuest Speaker: Gabe Aliaga, Geologist, Ridgeline Minerals  Title“From deep porphyry to shallow oxide and everything in between: A holistic approach to mineral exploration at the Selena project, White Pine County, Nevada”  Date:   FRIDAY, FEBRUARY 18, 2022  Time:  Drinks @ 6 pm, Dinner @ 6:30 pm, Talk @ 7:15 pm  WhereReno Aces Ball Park, 250 Evans St. Upstairs at the 250 Lounge/Good Hops Restaurant Abstract: The Selena property is a shallow-oxide, silver-gold-lead-zinc discovery made by Ridgeline Minerals in 2020. The project is located within the historic Limousine Butte district of the south Carlin-Trend with the claim block comprised of 467 contiguous federal lode claims totaling 39km². Historic and currently producing mines in the area include the Bald Mountain, Alligator Ridge, Yankee, Illipah and Golden Butte deposits. Preliminary trenching followed by four phases of drilling have defined a mineralized footprint that begins at surface and extends 1.3km E-W and over 2.0 km N-S with mineralization open in multiple directions. Follow-up drilling in 2021 confirmed the shallow oxide potential of the system while also intersecting higher-grade silver-lead-zinc zones at depth. The style of mineralization and proximity to a known copper-gold porphyry system located ~1km to the west of the property suggests the Au-Ag mineralization represents the outer halo of a zoned hydrothermal system, with potential to discover a previously unrecognized Carbonate Replacement (CRD) style deposit under relatively shallow cover. Ordovician through Pennsylvanian rocks crop out in the southern Cherry Creek Range and dip 20-30° to the west. Hosts for replacement-style mineralization include the Devonian Guilmette Limestone and the contact between Mississippian Joana Limestone and overlying Chainman Shale. Folds and thrusts with approximately N-S strikes are recognized in geologic mapping and in drilling; silicified outcrops are largely controlled by thrusts. Other important controls include younger, NE-striking faults showing the most offset and older, WNW faults showing less offset but appearing to control high-grade replacement mineralization. Undated quartz-feldspar porphyry intrusions crop out at the intersections of thrusts and west-northwest faults. Geometries of these intrusions appear to be irregular, discontinuous dikes and small plugs. Drilling thus far indicates the intrusions themselves do not carry grade, however they are spatially associated with mineralization and typically oxidized and argillized. Volcanic rocks 8 km north of the property give Eocene K-Ar ages and the Cherry Creek pluton 12 km to the northeast, along with its associated polymetallic mineralization, are also dated as Eocene. Intrusions at Selena are presumably Eocene, however the Butte Valley porphyry, adjacent to the property to the west, has a reported Cretaceous U-Pb zircon age of 98.5 Ma. The timing is similar to the Cretaceous copper porphyry of the Robinson Mining District 60 km south of Selena. Further investigation may find overprinting magmatism and/or mineralization, but a zonation in metals has been demonstrated by Ridgeline at Selena. Prospects east and north of the defined mineralized footprint show a greater Au/Ag ratio. Drilling to the west in 2021 targeted the mineralization at depth and showed increased Ag, Pb, and Zn across all drillholes. Highlight intercepts from the 2021 program include 4.6m grading 421 g/t Ag, 0.6 g/t Au, 4.4% Pb and 3.7% starting at 191m true vertical depth (TVD) in SE21-024, and 44.2m grading 123.2 g/t Ag, 0.1 g/t Au, 1.5% Pb and 0.6% Zn starting at 232m TVD in SE21-025. Decarbonatization, silicification, and brecciation of carbonate rocks characterize alteration at Selena. Contacts between altered and unaltered rock are sharp and parallel to controlling faults and bedding. Banded calcite veins often bound zones of mineralization and can be involved in silicified breccias. Hydrothermal dolomitization occurs in some areas as margins to mineralized zones. Argentiferous manganese oxide mineralization (AMOM) occurs in most zones and can continue as veinlets into surrounding unaltered rock. All intercepts drilled by Ridgeline thus far are oxidized and hematite-rich, but the western-most hole demonstrated a significant increase in sulfide content as well as the first instance of unoxidized intrusions on the property. Vectoring towards the buried copper porphyry to target sulfide (CRD) replacement mineralization is Ridgeline’s primary exploration focus in 2022 with a 5,500m drill program planned for mid-April.
Gabe Aliaga Bio:
Gabriel Aliaga was born and raised in Chicago to Bolivian immigrants and completed his B.S. in Earth & Environmental Sciences at the University of Illinois at Chicago. After working three years in a hospital analytical lab, he desperately missed the rocks, and was convinced by his then-girlfriend, now-wife to apply to graduate school. Gabe moved out west and completed his M.S. in Geology at the University of Nevada, Reno, in 2018. His thesis under Dr. Mike Ressel characterized and age-dated the igneous rocks and associated alteration of the Keystone window in the Simpson Park Mountains of north-central Nevada, adding to the importance of the Eocene epoch to Nevada’s gold endowment. After graduating, he worked for Nevada Exploration Inc. and helped advance the South Grass Valley project. Gabe is now with Ridgeline Minerals Inc. and busy merging boots-on-the-ground field work, 3D modeling, and drill targeting into an exciting adventure looking for the next big one. He lives in Sparks, NV, with his wife Naseem, dog Terra, and two cats, Astra and Luna.
 
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Reno, NV
Event StartsEvent Ends
02/18/202202/18/2022
All Day Event
6:00pm9:00pm