Lithogeochemistry of Geological Units in the Girardville Area
The tables below summarize the lithogeochemical characteristics of geological units in the Normandin area. These units are described in the Geological Bulletin covering this territory and in the Quebec Stratigraphic Lexicon. The 127 analyses used here come from samples collected during the Ministère‘s mapping campaign in the summer of 2019. They were selected based on certain criteria, including a sum of major oxides between 98.5% and 101.5% and a loss on ignition (LOI) <3%. These analyses were conducted by AGAT Laboratories.
Analyses were subject to an internal and laboratory quality assurance and control process. Thus, to ensure the accuracy and precision of the values provided by the laboratory, the Bureau de la connaissance géoscientifique du Québec (BCGQ) regularly inserts blanks, standards and duplicates. Reference materials represent ~10% of the analyses.
The majority of samples in the database were analyzed for major oxides, trace elements and metals. Analyses were performed using different techniques depending on elements, such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma optical emission spectrometry (ICP-AES) and neutron activation (INAA). For more information on the analysis and dissolution techniques used, refer to the information available for each sample in SIGÉOM à la carte.
The ICPW standard modified to include biotite and hornblende was calculated according to the method of Hutchison (1974, 1975) in the GeoChemical Data Toolkit software (GCDkit, Janoušek et al., 2006) to produce discriminant diagrams for intrusive rocks. This software was used to produce the geochemical diagrams mentioned in the tables below.
Rare earth elements are normalized according to the values of Palme and O’Neill (2004). Anomalous, distinctive or significant contents are shown in bold in the tables.
Felsic to Intermediate Intrusive Rocks
Stratigraphic or Lithological Unit | Classification | Affinity | Type of Magmatism | Mg# | Rare Earths (REE) | Tectonic Setting |
|---|---|---|---|---|---|---|
Coin Batholith (mPbcn) | Alkali feldspar granite (Diagram) | Enriched in K (shoshonitic series) (Diagram) | Ferriferous, alkaline-calcic and peraluminous
| 8.1 | (La/Yb)N = 33.80 (La/Sm)N = 3.37 (Gd/Yb)N = 5.85 Eu/Eu* = 0.52 (Diagram) |
Does not apply. |
Bolduc Intrusive Suite (mPblc) | Hypersthene monzonite (mangerite), quartz syenite, granite and hypersthene granite (charnockite) (Diagram) | Variable: calc-alkaline series to shoshonitic series (Diagram) | Mostly ferriferous, calcic to alkaline, metaluminous to peraluminous | 5.32-34.23 | 5.31 < (La/Yb)N < 22.99 3.03 < (La/Sm)N < 8.20 1.06 < (Gd/Yb)N < 3.75 0.35 < Eu/Eu* < 1.11 (Diagram) | Mostly volcanic arc granite (Diagrams) |
Jean-Marie Intrusive Suite (mPijm) | Quartz syenite, hypersthene quartz syenite, alkali feldspar granite, granite and hypersthene granite (charnockite) (Diagram) | Shoshonitic to calc-alkaline enriched in K series (Diagram) | Ferriferous, calc-alkaline to alkaline, metaluminous to peraluminous | 4.93-18.29 | 5.14 < (La/Yb)N < 74.68 2.82 < (La/Sm)N < 8.84 1.25 < (Gd/Yb)N < 3.33 0.27 < Eu/Eu* < 3.83 (Diagram) | Volcanic arc to within-plate granite (Diagrams)
|
Sainte-Hedwidge Intrusive Suite 2 (mPshe2) | Quartz syenite, syenogranite, alkali feldspar granite (Diagram) | Calc-alkaline, calc-alkaline enriched in K and shoshonitic series (Diagram) | Mostly ferriferous, calc-alkaline to alkaline-calcic, metaluminous to peraluminous | 3.51-27.45 | 3.68 < (La/Yb)N < 29.30 1.36 < (La/Sm)N < 5.73 1.36 < (Gd/Yb)N < 3.94 0.64 < Eu/Eu* < 2.34 (Diagram) | Mostly volcanic arc granite (Diagrams) |
Vertu Plutonic Suite (mPvet) mPvet1 mPvet2 | mPvet 1 Alkali feldspar granite, quartz syenite mPvet2 Alkali feldspar granite, syenogranite, syenite, quartz syenite and hypersthene syenite (Diagram) | mPvet 1 Shoshonitic series mPvet2 Calc-alkaline, calc-alkaline enriched in K and shoshonitic series (Diagram) | mPvet1 Ferriferous, alkaline-calcic to alkaline, metaluminous to peraluminous mPvet2 Ferriferous to magnesian, calc-alkaline to alkaline, metaluminous to peraluminous | mPvet1 9.78-19.74; mPvet2 7.58-3.71 | mPvet1 11.41 < (La/Yb)N < 31.74 2.56 < (La/Sm)N < 3.12 2.38 < (Gd/Yb)N < 5.53 0.53 < Eu/Eu* < 0.76 mPvet2 5.14 < (La/Yb)N < 22.74 2.14 < (La/Sm)N < 7.23 1.13 < (Gd/Yb)N < 3.10 0.65 < Eu/Eu* < 4.50 (Diagram) |
mPvet1 and mPvet2 Mostly volcanic arc granite (Diagrams) |
Bois Vert Plutonic Suite(mPbvr) mPbvr1 mPbvr2 mPbvr3 | Syenite, quartz syenite, syenogranite, hypersthene syenogranite (charnockite), alkali feldspar granite, alkali feldspar syenite ± alkaline syenite and foid monzonite (Diagram) | Mostly shoshonitic series (Diagram) | Mostly ferriferous and alkaline, metaluminous to peraluminous | 13.46-25.88 |
11.22 < (La/Yb)N < 73.12 2.26 < (La/Sm)N < 5.93 2.08 < (Gd/Yb)N < 5.89 0.27 < Eu/Eu* < 1.56 (Diagram) | Within-plate to volcanic arc granite (Diagrams) |
Saint-Thomas-Didyme Suite 2 (mPstd2) | Mostly alkali feldspar granite, syenogranite, hypersthene monzonite (mangerite) and hypersthene quartz monzonite (Diagram) | Calc-alkaline, calc-alkaline enriched in K and shoshonitic series (Diagram) | Mostly ferriferous, calc-alkaline to alkaline, metaluminous to peraluminous | 2.31-26.31 | 3.76 < (La/Yb)N < 49.67 1.76 < (La/Sm)N < 6.29 1.31 < (Gd/Yb)N < 3.63 0.23 < Eu/Eu* < 1.05 (Diagram) | Mostly volcanic arc granite (Diagrams) |
Metasedimentary Rocks: Barrois Complex (mPboi)
Stratigraphic or Lithological Unit | Classification | Protolith and alteration |
|---|---|---|
Barrois Complex 4 (mPboi4) |
Paragneiss, biotite ± graphite paragneiss, migmatite derived from sedimentary rocks, calcosilicate rocks |
Sedimentary rocks derived from the upper crust (tonalite, granodiorite and granite). Generally, metasedimentary rocks are slightly altered and biotite-graphite paragneiss is locally more altered. (Diagram) |
Barrois Complex (mPboi, mPboi4c) | Quartzite, garnetite and metasomatic rocks
| Sedimentary rocks derived from the upper crust (mostly tonalitic). Generally, metasedimentary rocks are slightly to moderately altered. (Diagram) |
Mafic-Ultramafic Rocks
Stratigraphic or Lithological Unit | Classification | Affinity | Mg# | Total REE | Rare earths (REE) | Comments |
|---|---|---|---|---|---|---|
Jean-Marie Intrusive Suite (mPijm) | Gabbronorite, Fe-Ti oxide gabbronorite | Calc-alkaline to tholeiitic (Diagram) | 13.60-45.23 | 63-309 ppm | 3.33 < (La/Yb)N < 22.66 1.47 < (La/Sm)N < 3.62 1.57 < (Gd/Yb)N < 4.08 0.81 < Eu/Eu* < 1.16 (Diagram) | Analyzed samples are mostly coarse grained and their chemistry does not really represent the global composition of the protolith. They are also more or less enriched in sulphides and Fe-Ti oxides (hemo-ilmenite, ilmenite, magnetite). |
Bois Vert Plutonic Suite (mPbvr1, 2 and 3)
| Gabbronorite, pyroxenite | Tholeiitic (Diagram) | 22.15-31.81 | 39-623 ppm | 1.76 < (La/Yb)N < 27.44 1.11 < (La/Sm)N < 2.79 1.22 < (Gd/Yb)N < 5.26 0.57 < Eu/Eu* < 1.20 | Analyzed samples are mostly medium to coarse grained and their chemistry does not really represent the global composition of the protolith. They are also more or less enriched in sulphides and Fe-Ti oxides. |
Suite de Saint-Thomas-Didyme 2 (mPstd2) | Gabbronorite, gabbro, diorite | Tholeiitic (Diagram) | 20.25-23.84 | 319-500 ppm | 16.62 < (La/Yb)N < 19.09 2.55 < (La/Sm)N < 3.18 3.11 < (Gd/Yb)N < 4.41 0.89 < Eu/Eu* < 1.01 (Diagram) | Presence of Fe-Ti oxides in a sample (20-AM-05A-1) |
Sainte-Hedwidge Intrusive Suite 2 (mPshe2) | Gabbronorite | Tholeiitic (Diagram) | 25.18-40.73 | 60-169 ppm | 3.25 < (La/Yb)N < 3.62 1.45 < (La/Sm)N < 1.72 1.65 < (Gd/Yb)N < 1.93 0.94 < Eu/Eu* < 1.00 (Diagram) | Fine to medium-grained gabbronorite enriched in Fe-Ti oxides |
Rocks Mineralized in Rare Earth Elements (REE)
Lithology | Classification | Affinity | Mg# | Total REE | Rare Earths (REE) | Comments |
|---|---|---|---|---|---|---|
Pegmatitic dykes and lithologies enriched in rare earth elements | Syenogranite, alkali feldspar quartz syenite, alkali feldspar syenite (Diagram) | Metaluminous to peraluminous (igneous to sedimentary origin) (Diagram) | 5-29.5 | 1056-10561 ppm | 64.99 < (La/Yb)N < 248.63 4.02 < (La/Sm)N < 10.20 3.37 < (Gd/Yb)N < 30.44 0.15 < Eu/Eu* < 0.59 | Analyzed samples are mostly coarse grained to pegmatitic and their chemistry does not really represent the global composition of the rock. |
Girardville carbonatite | Calcitic carbonatite (Diagram) | Peralkaline (Diagram) | 41.93 | 1539 ppm | (La/Yb)N = 15.08 (La/Sm)N = 3.98 (Gd/Yb)N = 2.30 Eu/Eu* = 0.98 (Diagram) | Carbonatite contains biotite, and microcline and ilmenite megacrysts |
References
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