Geological map of the upper Pellice Valley (Italian Western Alps)

(1)

28 July 2021

AperTO - Archivio Istituzionale Open Access dell'Università di Torino

Original Citation:

Geological map of the upper Pellice Valley (Italian Western Alps)

Published version:

DOI:10.4113/jom.2011.1213

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Com_ba dell'U rina 2600 2400 2200 2000 1800 1600 1400 1200 2457 2547 2585 2454 2105 2776 2863 2668 2997 2110 2238 2628 2614 1907 2189 2653 1732 2393 2110 1490 1954 2017 2542 1787 1653 1155 1080 Eyssard Burfaran Col Bucie Curnaliot Monte Giulian Torrente C_ruello Bric Bucie Col Bancet T. Pellice Col Malaura Col Content Alpe Bancei Rocca Capus Torrente Crosenna Col di Boina Colle Giulian Punta Fiunira Passo di Brard Passo Dar Loup Punta Cerisira Punta Resiassa Alpe Crosenna Alpe Giulian Punta Giornivetta Colletta delle Faure 26 0 0 2400 2200 2000 1800 1600 1800 2000 22 00 24₀₀ 24 00 22 00 2 0 0 0 3000 2800 260 0 2400 2000 2200 26 00 2400 2200 20 00 1800 2600 ₂₄00 2200 20 00 18 00 16 0 0 2200 2000 1800 1600 1400 Bufafol Mirabuc Punta Fiunira Colletta Lago Lungo Lago Gelato Monte Pistas Villanova Castellus Lago Losere Monte Manzol Lago Nero Monte Palavas T.P ellic e Col Porsel Punta Pleng Monte Cappello Rocca Nera Monte Granero Monte Custassa Gran Gorgia Grange del Pis Rocca Bianca Monte Gianzana Truc Pailly L. Arbancie Monte Meidassa Colle Armoine Torr ente Ghic ciar d Colle Vecchio La Gugliassa Grange del Pis Colle Vittona L'Agugliassa Lago Piena Sia Alpe la Rossa L. Mal Consej Rifugio Granero Colle Manzol Colle Seilliere Ciabot del Prà

Chiot dei Salè

Partia d'Amunt Guglion Grande Colle della Mait Colle Proussera Punta Sea Bianca Colle dell'Urina

Colle del Baracun

Colle della Croce Passo Seillierino Colle della Gianna Grange della Gianna 2198 2555 2450 2389 2125 2356 2567 2651 2884 2192 1904 2799 2523 ₂₆₆₀ 1429 1925 1637 2928 1993 2219 2069 2424 2329 1736 2369 2545 1696 2301 2361 2264 2659 1743 2675 1757 2686 2581 2224 1820 2793 2837 2162 2460 2666 2932 2881 2391 2709 2532 2993 3107 3171 2861 2689 C B A C' B' A' Bc Bc Mb Gc Bc Mb Bc Gc Mc Ms Ms Ug Mb Ld Dm Ld Ug Gc Bc Gc Tl Ms Tl Dm Ms Fl1 Mc Gd Tl Tl Mb Dg Ug Mb Ug Ld Tl Tl Rg2 Tl Mg Mc Ug Mg Dg Ld Tl Ms Mc Tl Tl Bc Mc Tl Ug Tl Ms Tl Mb Gd Ug Tl Tl Tl Gd Tl Mc Mc Tl Ug Tl Ld Fl1 Tl Tl Fl1 Bc Ms Ld Dm Rg2 Ug Ld Tl Ms Dg Ld Rg1 Td Ug Tl Ld Ug Fl1 Ld Fl2 Rg1 Gm Bg Gc Ld Tl Tl Td Gc Mb Mb Ld Gc Td Tl Fl1 Mc Fl1 Ms Td Fl1 Ld Mc Rg2 Tl Mg Td Fl1 Tl Dg Td Td Tl Ms Tl Ug Ug Ld Ug Dm Ug Tl Fl2 Tl Fl2 Bc Rg2 Td Me Mc Tl Bb Tl Td Tl Ms Ug Ms Mg Ms Bc Tl Tl Fl1 Tl Td Tl Fl1 Ms Tl Rg2 Fl2 Tl Fl2 Td Td Fl1 Tl Ld Mc Rg1 Rg2 Fl2 Fl1 Rg1 Fl1 Tl Rg2 Td Rg2 Td Mc Tl Mb Fl1 Mb Td Gd Tl Fl2 Ms Ms Me Fl1 Ug Mc Ld Rg2 Ld Me Rg2 Tl Fl1 Gm Bm Fl1 Bq Fl1 Fl1 Td Bb Rg2 Tl Fl1 Bb Fl1 Ug Fl1 Me Mb Mc Me Gd Bb Dq Ms Fl1 Fl1 Fl2 Dq Dq Mg Dq Fl2 Fl1 Ld Bq Mg Fl1 Td Bc Td Mc Bm Me Fl1 Ug Td Fl1 Bb Bb Bs Bb Bq Td Mb Fl1 Ug Bs Ms Bs Bm Bb Dm Mg Mb Dq Bq Bg Bs Mb 8 2 9 2 9 7 8 5 5 1 2 5 5 8 1 5 3 8 5 5 8 9 2 5 6 39 10 10 20 11 48 10 10 10 20 47 19 29 40 40 60 32 25 10 19 30 10 12 11 23 11 10 10 12 30 18 10 15 18 30 30 35 16 15 37 20 26 10 15 15 25 18 28 31 5 22 27 26 33 40 20 10 33 31 36 26 38 29 55 28 20 45 53 58 39 65 58 37 45 45 20 60 35 27 33 55 62 80 72 27 28 40 41 59 57 31 46 35 49 40 40 45 25 80 35 21 30 48 28 52 55 49 30 75 35 60 13 70 42 60 51 33 50 31 53 32 68 65 46 34 39 29 46 39 27 35 32 45 52 42 66 58 27 52 31 32 33 28 35 37 45 36 25 51 80 48 33 28 20 60 56 20 40 31 49 33 19 32 85 42 57 65 38 50 44 20 32 44 23 32 35 18 22 14 30 30 22 69 37 52 41 51 29 39 23 61 41 52 39 36 70 78 40 40 34 41 29 52 29 42 22 39 47 28 73 47 30 24 32 34 30 37 37 34 30 31 35 23 44 27 50 40 35 50 30 40 30 35 25 40 49 50 50 40 30 30 43 40 50 30 60 45 50 40 78 50 15

N

S

W

E

The Geological Map of the Upper Pellice Valley was compiled from geological surveys by

G. Arduino, J.G. Brasher, M. Rattalino, R. Nervo and B. Lombardo (1983-1984), and from new

lithological, structural and morphological observations by the Authors (2009-2010).

The topographic map derives from the Carta Tecnica Regionale of the Regione Piemonte

(vector_50 series; Coordinate System WGS 1984 UTM Zone 32N; authorization n.15/2010).

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Scale 1:25,000

GEOLOGICAL MAP OF THE UPPER PELLICE VALLEY (ITALIAN WESTERN ALPS)

Gianni Balestro

(1)

_{, Gianfranco Fioraso}

(2)

_{& Bruno Lombardo}

(2)

(1) Dipartimento di Scienze della Terra, Università degli Studi di Torino, Via Valperga Caluso 35, 10125 Torino, Italy

(2) Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche, Via Valperga Caluso 35, 10125 Torino, Italy

Lithological contact Syn-metamorphic fault

Post-metamorphic fault (dashed where inferred) Normal post-metamorphic fault (dashed where inferred; ticks on downthrown side)

Main foliation (Sp) Pre-Sp foliation Post-Sp foliation Syn-Sp fold axis Post-Sp fold axis 10

10 10

10

Alluvial and debris flow fan Mixed fan

Talus fan Glacial moraine Protalus rampart Rock glacier ridge Trench

Counter-slope Yelding surface

Deep-seated gravitational slope deformation Trace of cross section

A A'

QUATERNARY DEPOSITS

PRE-QUATERNARY TECTONIC UNITS

BUCIE-SEILLIERE UNIT

MONVISO UNIT

GIULIAN-SEA BIANCA UNIT

Fine-grained calcschists with levels of micaceous marble and micaschist, mainly phyllitic in the lower part of the sequence and more carbonatic in the upper part (Bc). Early Cretaceous? - Late Cretaceous?

Bc

Levels of medium-grained micaschist (Colle Seilliere, east of Colle della Croce, north of Alpe Crosenna) (Bm). Early Cretaceous? - Late Cretaceous?

Bm

Undifferentiated white marbles, micaceous quartzites and layers of metabasite deriving from gabbroic and basaltic sandstones (Monte Palavas, Bric Bucie) (Bq). Late Jurassic?

Bq

Bodies of fine-grained metabasite mostly deriving from basaltic rocks (Bb). Middle

Jurassic?

Blueschist-facies metagabbros with well-preserved magmatic fabric (Monte Palavas)

(Bg). Middle Jurassic?

Bb

Bg

Levels of serpentinized cumulate peridotite (Monte Palavas) (Bs). Bs

Alluvial and debris flow deposits, composed of gravelly cobbles and sandy gravels, clast-supported, massive to well stratified, sometimes containing decimetric-scale boulders(Fl1). Late Upper Pleistocene - Present

Fl1

Ancient alluvial and debris flow deposits, composed of clast-supported gravelly cobbles with sandy matrix, clast-supported, massive to crudely stratified, sometimes containing decimetric-scale boulders (Fl2). Late Upper Pleistocene - Holocene

Fl2

Mixed talus and debris flow deposits, composed of angular clasts, cobbles and gravels with crude stratification, clast supported, sometimes with partially openwork texture

(Td). Late Upper Pleistocene - Present

Inactive rock glacier, composed of poorly sorted angular blocks, at surface, and blocks and fine material below the surface. Block surfaces are lichen covered (Rg2). Holocene Active rock glacier, composed of poorly sorted angular blocks, at surface, and blocks and fine material with interstitial ice, below the surface. Block surfaces are devoid of lichens (Rg1). Holocene - Present

Undifferentiated glacial deposits, made up of diamicton with silty-sandy matrix containing faceted, smoothed and striated clasts and boulders (lodgement till) and chaotic blocks accumulation with silty-sandy matrix (ablation till) (Ug). Upper Pleistocene Talus deposits, composed of well sorted centimetric to decimetric angular fragments and blocks, clast supported, with openwork to partially openwork texture (Tl). Late Upper Pleistocene - Present

Landslide deposits, composed of chaotic accumulation of angular blocks with scanty matrix or large loosened portions of bedrock (Ld). Late Upper Pleistocene - Present Tl Td Ld Ug Rg1 Rg2

DORA-MAIRA UNIT

Medium-grained calcschists with levels of fine-grained micaceous marble; (a) meter-scale lenticular bodies of metabasite (Monte Giulian, Colletta delle Faure, NW and SW of Alpe La Rossa, north of Grange del Pis) (Gc). Jurassic? - Cretaceous? Gc

a

Level of medium-grained garnet-bearing micaschist (east of Colletta delle Faure) (Gm). Jurassic? - Cretaceous?

Gm

Bodies and levels of white to grey fine-grained metadolostone, dolomite marble and banded mica-bearing marble (Gd). Middle Triassic - Late Triassic?

Gd

Undifferentiated metasedimentary cover of the Paleozoic basement: carbonate micaschists, yellowish marbles, quartzites and paragneisses (Colle Giulian, Burfaran, south of Eyssard, Alpe La Rossa, Grange della Gianna) (Dq). Early Triassic?

Dq

Medium- to coarse-grained K-feldspar-bearing orthogneisses, with variably preserved magmatic fabric, and fine-grained leucocratic gneisses (Dg). Early Permian?

Dg

Medium-grained garnet-chloritoid-bearing micaschists and fine-grained paragneisses

(Dm); (a) lenticular bodies of fine-grained garnet- and glaucophane-bearing metabasite

(north and south of Eyssard, Alpe La Rossa). Pre-Carboniferous? Dm

a

Medium-grained calcschists, micaceous marbles and quartz-rich micaschists, locally with blocks of banded metabasite, serpentinite and eclogitic metaferrogabbro, and layers of metabasite deriving from gabbroic sandstones (Colle del Baracun, Mirabuc, Villanova) (Mc). Late Jurassic? - Cretaceous?

Mc

Banded amphibole-epidote metabasites with relics of glaucophane and garnet, with poorly-preserved magmatic fabric (pillow lavas and breccias), locally transformed into greenschists (Col Bancet, Colletta delle Faure, Colle Manzol, Rocca Capus) (Mb). Late Jurassic?

Mb

Greenschist-facies Al-Mg metagabbros (Mg) and locally preserved (Colle Dar Loup,

east of Monte Manzol) "Smaragdite" Al-Mg metagabbro (a). Middle Jurassic?

Eclogite-facies Fe-metagabbros and fine-grained glaucophane-bearing eclogites (Me).

Middle Jurassic? Me

Massive antigorite serpentinites and antigorite schists, locally with metamorphic olivine

(Ms); (a) main metarodingite dykes (Colle Dar Loup, Colle del Baracun, Colle della

Gianna, Rocca Nera, Villanova). Mg a Ms a Punta Cournour 2867 Punta Fiunira 2776 Bric Bucie 2997 Monte Palavas 2928 Monte Custassa 2675 Monte Cappello 2837 Monte Pistas 2881 Monte Granero 3171 Monte Meidassa 3104 Monte Manzol 2932 l’Agugliassa 2793 Rocca Nera 2709 Punta Sea Bianca 2720 T. Pellic e T. Ghicc iard T. Subiasco Col Bucie 2628 Colle dell’Urina 2523 Colle della Croce 2301

Colle del Baracun 2369

Punta Pleng 2656

Ciabot del Pra

Villanova Monte Giulian 2547 L. Lungo Grange del Pis Comba del la G ianna 0 1 2 km

Geomorphological

sketch map

E

7°

C

W

Lago Lungo Bc

C'

Mc Ms Mb Colle Manzol Mb Mc Mc Ms _Gc Gd

E

Cross sections

Plio-Quaternary deposits Tertiary sediments

External Crystalline Massifs (PE: Pelvoux; AG: Argentera) Helvetic-Dauphinois Units

Ivrea Zone Canavese Zone

Helminthoid flysch Blueschist Piedmont Zone

Eclogitic Piedmont Zone (MO: Monviso) Lanzo Ultrabasic Complex

Briançonnais Zone (A: Acceglio Zone)

Internal Crystalline Massifs (DM: Dora-Maira; GP: Gran Paradiso) PENNINIC UNITS

EXTERNAL UNITS SOUTHERN ALPS

Sesia-Lanzo Zone AUSTROALPINE UNITS

Tectonic sketch map of the Western Alps.

The inset shows the study area.

Monviso

Pellice Valley