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)

1 sample

Alkali feldspar granite

(Diagram)

Enriched in K (shoshonitic series)

(Diagram)

Ferriferous, alkaline-calcic and peraluminous

(Diagrams A, B and C)

 

 

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)

6 samples

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

(Diagrams A, B and C)

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)

14 samples

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

(Diagrams A, B and C)

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)

13 samples

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

(Diagrams A, B and C)

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

3 samples

mPvet2

8 samples

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

(Diagrams A, B and C)

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

Bois Vert Plutonic Suite(mPbvr)

mPbvr1

2 samples

mPbvr2

7 samples

mPbvr3

3 samples

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

(Diagrams A, B and C)

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)

15 samples

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

(Diagrams A, B and C)

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)

21 samples

 

 

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)

6 samples

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)

5 samples

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)

9 samples

 

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

(Diagram)

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)

3 samples

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)

3 samples

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

7 samples

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)N248.63

4.02 < (La/Sm)N < 10.20

3.37 < (Gd/Yb)N < 30.44

0.15 < Eu/Eu* < 0.59

(Diagram)

Analyzed samples are mostly coarse grained to pegmatitic and their chemistry does not really represent the global composition of the rock.

Girardville carbonatite

1 sample

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

 

CHAPPELL B.W., WHITE A. J.R., 1974. Two contrasting granite types. Pacific Geology; volume 8, pages 173-174.

DEBON, F., LEFORT, P., 1983. A chemical-mineralogical classification of common plutonic rocks and associations. Transactions of the Royal Society of Edinburgh, Earth Sciences; volume 73, pages 135-149. doi.org/10.1017/S0263593300010117.

FOLEY, S.F., VENTURELLI, G., GREEN, D.H., TOSCANI, L., 1987. The ultrapotassic rocks: Characteristics, classification, and constraints for petrogenetic models. Earth-Science Reviews; volume 24, pages 81-134. doi.org/10.1016/0012-8252(87)90001-8

FROST, B.R., BARNES, C., COLLINS, W.J., ARCULUS, R.J., ELLIS, D.J., FROST, C.D., 2001. A Geochemical Classification for Granitic Rocks. Journal of Petrology; volume 42, pages 2033-2048. doi.org/10.1093/petrology/42.11.2033

HUTCHISON, C.S., 1974. Laboratory Handbook of Petrographic Techniques. John Wiley & Sons, New York, pages 1-527.

HUTCHISON, C.S., 1975. The norm, its variations, their calculation and relationships. Schweiz Minera, Petrogr Mitt. volume 55, pages 243-256.

IRVINE, T.N., BARAGAR, W.R.A., 1971. A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences; volume 8, pages 523-548. doi.org/10.1139/e71-055

JANOUŠEK, V., FARROW, C.M., ERBAN, V., 2006. Interpretation of whole-rock geochemical data in igneous geochemistry: introducing Geochemical Data Toolkit (GCDkit). Journal of Petrology; volume 47, pages 1255-1259. doi.org/10.1093/petrology/egl013

MANIAR, P.D., PICCOLI, P.M., 1989. Tectonic Discrimination of Granitoids. Geological Society of America Bulletin; volume 101, pages 635-643. doi.org/10.1130/0016-7606(1989)101<0635:TDOG>2.3.CO;2

MIDDLEMOST, E.A.K., 1994. Naming Materials in the Magma/Igneous Rock System. Earth-Science Reviews; volume 37, pages 215-244. doi.org/10.1016/0012-8252(94)90029-9

NESBITT, H.W., 2003. Petrogenesis of siliciclastic sediments and sedimentary rocks. In Geochemistry of Sediments and Sedimentary Rocks: Evolutionary Consideration to Mineral Deposit-Forming Environments (Lentz, D.R., editor). Geological Association of Canada; volume 4, pages 39-51.

PALME, H., O’NEILL, H.S.C., 2004. Cosmochemical estimates of mantle composition. In Treatise on Geochemistry (Holland, H.D. and Turrekian, K.K. editors). Elsevier, Amsterdam, The Netherlands; volume 2, pages 1-38. doi.org/10.1016/B978-0-08-095975-7.00201-1

PEARCE, J.A., HARRIS, B.W., TINDLE, A.G., 1984. Trace element discrimination diagram for tectonic interpretation of granitic rocks. Journal of Petrology; volume 25, pages 956-983. doi.org/10.1093/petrology/25.4.956

PECCERILLO, A., TAYLOR, S.R. 1976. Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey. Contributions to Mineralogy and Petrology; volume 58, pages 63-81. doi.org/10.1007/BF00384745

SHAND, S.J., 1943. The eruptive rocks: 2nd edition, John Wiley, New York, 444 pages.

STRECKEISEN, A., 1976. To each plutonic rock its proper name. Earth-Sciences Review; pages 1-33. doi.org/10.1016/0012-8252(76)90052-0

WOOLLEY, A.R., KEMPE, D.R.C., 1989. Carbonatites:nomenclature, average chemical compositions, and element distribution. In Carbonatites: Genesis and Evolution (Bell, K., editor). Chapman & Hall, London, U.K., pages 1-14.

 

 

 

 

 

8 décembre 2021