433000 435000 437000 439000 441000

550 550 16° 10° 11° 12° 13° 14° 15° 650 500 M. Orfano b) Simplified tectonic outline of the Alps after Pianezza 5° 6° 7° Munich 48° 48° 8° 9° Handy et al. (2005). Pianceri N Riale Carnascio 450 Basel Torrente 500 700 600 Sessera

Graz 47° Gila 47° Bern

750 46° 46° 800 Valpiana Zagreb di LINE Croso Venice LINE Adriatic 100 km units PRAY 45° 45° 500 Sea 500 450 Outline of the 15° 16° Azoglio 11° 12° 13° 14° Val Lakes Massif 450 INSUBRIC A' Geological map of the Pennine Helvetic and POGALLO Castagnea 400 44° Austroalpine d'Ossola 550 Ultrahelvetic Domain 500 Ligurian Sea Domain Sessera 6° 7° 8° 9° 10° Penninic Domain Southalpine Maggiore and Pre-Alps Domain Val 600 Tertiary plutons 650 LINE Lago Torrente 650 pluton (Piemonte, ) 400 Val CMB N Lago Galfione 600 Ropolo d'Orta Plain Crosa 450 LINE (1) (2) (3) (3) (2) Crosa Tavazzani Lorenzo , Peres Stefano , Sinigoi Silvano , Demarchi Gabriella , Musumeci Giovanni 500 Val della 10 km Ronco 450 del sera LINE Ses 500 AUSTRO-ALPINE DOMAIN Pianaccia 550 Prete (1) Dedman College of Humanities and Sciences, Southern Methodist University, Dallas, US N 550 Flecchia Sesia Zone Mucengo

650 (2) Dipartimento di Scienze della Terra, Università degli studi di Pisa, Italy INSUBRIC SOUTHERN-ALPINE DOMAIN Guala CREMOSINA Permian-Mesozoic volcanic Rio Barbero 450 600 (3) Dipartimento di Matematica e Geoscienze, Università degli studi di Trieste, Italy 5057000 5057000 and sedimentary rocks

Coggiolasca Permian granitic rocks 500 (Lake’s granites) Outline of 650 SERIE DEI LAGHI map area 550 500 km IVREA-VERBANO ZONE Mafic Complex Ponzone Units Explanation: Geological sketch map Ronco Valle Fredda 600 a) DEM of the italian peninsula, c) Lakes Massif geological map Kinzigite Formation Canale the Alps profile is outlined. after Zingg (1983). Mantle Peridotite 435074 439074 Vico 550 SURFICIAL DEPOSITS EXPLANATIONS OF MAP SYMBOLS 600 Pratrivero Riale Solesio Torrente 650 Grosso 1250 Alluvium 900 950 Mazza Moialunga Boulders, cobbles, gravel, sand, and silt underlying present flood plains are 45 N 1200 700 Strike and dip of volcanoclastic sediments and eutaxitic 1000 Trabuldo A' Cereie 500 700 Qa mapped as alluvium. Pramorisio foliation in pyroclastic rocks 1050 HOLOCENE Pray 750 45

550 la Colma 600

1100 S.S Terraced deposits Strike and dip of bed in sedimentary rocks Trivero 1150 Bulliana

650 0 1 2 km N. 232 800 Riale Poorly consolidated to unconsolidated materials ranging in grain size from 850 Monte boulders to clay and deposited up to 30 to 40 m above the currently active 45 Mazzucco Qt Cattivo 500 550 Pisciavacche flood plains are mapped as terrace deposits. 600 Strike and dip of foliation and banding in metamorphic rocks Pratrivero PLEISTOCENE - HOLOCENE 700 Capo Mosso 500 550 Sedimentary deposits, undivided 550 45 600 450 Moderately consolidated deposits of conglomerate, sandstone, and shale la Valle Strike and dip of foliation and banding in igneous rocks Sella Ponzone 750 Ponzone Valle Qtu with minor carbonate are mapped as undivided Tertiary to Quaternary

650 Vaudano 5056000 sedimentary deposits. These are distinguished from other surficial deposits 5056000 Fila Rif.o La Sella 45 by greater consolidation and moderate dips of up to 20°. Monte Orbetto Comune Dip of fault planes 650 TERTIARY - QUATERNARY Mosso S. Maria 700 M. Solivo M. Orbetto Baltigati 650

Ponzone 600 550 Crocemosso MOSSO TERTIARY MAGMATISM OF THE WESTERN ALPS Contact: solid where observed, dashed where Monte Localà 500 S. Bononio 450 approximately located, dotted where concealed Monte Bastia Torrente Dikes related to Alpine orogenic magmatism 550 500 550 B'' 500 Gradational contact : solid where observed, dashed B' Variably porphyritic basalts, basaltic andesites and andesites dikes that A Valle Mosso where approximately located. 600 belongs to the calcalkaline and shoshonitic series, that contains various 5055000

5055000 fAb 600 proportions of hornblende, clinopyroxene, plagioclase phenocrysts and Colma Fault, showing dip where measured. Dashed where 750 M. Capoposto minor biotite. 700 Vivaro Colmo approximately located, dotted where concealed. Cerruti 550 OLIGOCENE

550 500 500 650 600 Monte Rovella Cerruti 550 IGNEOUS ROCKS OF PERMIAN AGE A' Pistolesa Traces of the geological cross sections 550 A Strona 550

Cerreia 450 VOLCANIC ROCKS OF THE SESIA CALDERA

5052000 5052000 600 Ordivaro B 450 Monte Localà Rhyolitic rocks Piane 500 Orange to red-weathering volcanic and hypabissal rhyolite porphyry that delle SOPRANA contains small (0.5-3 millimetre (mm)) crystals of quartz and feldspar Lago 450 Crocemosso 650 r 550 550 Orzera dispersed in a pink aphanitic matrix. Includes ignimbrite with abundant 500 fiamme and eutaxitic textures, volcanic breccia and massive porphyry. 550 500 600 Andesitic lava flows are also reported to form decametric-scale concordant 500 Lanvario 500 bodies within the main rhyolitic body. 500 600 450 S. Bononio PERMIAN 500 Calvino 550 500 500 VALLE MOSSO DIKES SYSTEM M. Bastia 550 Ronco 650 Quartz dikes Drift and solid map Mad.na del Sabbione 450 Hydrothermal origin, mainly quartz-made dikes. Orcurto 500 B'' Due to the poor exposure of bedrock in the surveyed area, the inferred 450 450 fq PERMIAN lithostratigraphic configuration has been represented on a ‘drift and solid’ 600 435074 439074 B' 600 400 map, in which surfacing rocks are separated by drift cover. 431074

550 A 400 Vergnago The distinction between outcropping and covered bedrock has been Doleritic and dioritic dikes A' highlighted on the map with a different intensity of the colours indicating Units explanation Valle Mosso pluton Traces of the geological Mafic-dikes ranging from basaltic to dioritic in composition. They present the geological units. A 500 cross sections disrupted margin usually associated with swarms of fine-grained enclaves Montaldo 550 fb Surficial deposits Equigranular pink monzogranite of hybrid dioritic magma into the granitic host-rock. Contacts between 550 VALLE MOSSO Premarcia 500 Equigranular white monzogranite intrusive units 500 PERMIAN Rhyolitic rocks Sub-outcropping bedrock Contacts between ROSSE 450 Porphyritic monzogranite 450 geological units Strona Piana Foglio Mino Mafic plutonic rocks 500 450 Microgranitic porphiry Contacts between S. Rocco VALLE MOSSO INTRUSIVE BODY 550 400 bedrock and cover 5053000 S. Martino 5053000 Undivided paragneiss Two-mica leucogranite Strike-slip fault Role Equigranular pink leucomonzogranite Outcropping bedrock Undivided orthogneiss 700 (certain, inferred) S. Nicolao 400 Granodioritic monzogranite 500 400 400 400 Equigranular medium-grained leucogranites, usually bright pink, with 550 600 RIVE vgrU isotropic textures composed of mm-sized K-feldspar, quartz, biotite and 450 rare plagioclase crystals. Granophyric texture domains are locally abundant. Rare cm-sized miarolitic cavities and pegmatitic pockets are 650 Cedreie 400 Falcero 450 also present.

450 400 Upper Valle Mosso Facies Valle Piana Fangazio LE Bioletto M. Rovella Bugelio PERMIAN 500 Granitic facies and conceptual model Mondalforno Equigranular white monzogranite 850 400 350 Equigranular medium- to coarse-grained monzogranites that show an isotropic texture composed of cm-sized K-feldspar, plagioclase and quartz 450 400 350 Torrente Bric Montuoso vgrE crystals with ≈ 5% biotite occurrence. A B 0 km

800 Zoppo 400 Montaldo Facies 400 Campore dello 350 PERMIAN Cigliaga Rio 750 Strona 350

Rio 450 Fontanella-Ozino 450 400 Microgranitic porphyry Torrente 350 Markedly porphyric granitoid rocks composed of cm-sized K-feldspar, 700 350 2 km 400 Bisignana plagioclase and quartz crystals in a quasi-aphanitic biotite-rich matrix.

400 vgrM 650 Countless small biotite–rich enclaves, rapakivi and anti-rapakivi reaction Cagne 400 Caudana rims and resorbed quartz crystals are peculiar features of this granitic facies. Gabella Bric Mazzero Monte Bastia Facies Alcinengo della PERMIAN 4 km

600 CASAPINTA Markedly inequigranular to porphyritic monzogranite 1 cm 1 cm STRONA Riale 400 350 Medium-grained monzogranites, inequigranular for euedral cm-sized (2- 4 Mornengo 450 350 Bosi cm) K-feldspar crystals, plagioclase, quartz and ≈ 10% biotite. Locally vgrP abundant mafic microgranular enclaves. 6 km B 350 C D 300 Vaudano Facies Aimone PERMIAN

Ferrere 350 Piane 400 Two-mica leucogranite 5051000 400 5051000 Fine-grained muscovite-rich leucogranites. Equigranular rocks that show 8 km 550 Gianadda Colongo an isotropic texture made up of K-feldspar, plagioclase, quartz, muscovite 500 delle vgrF Quario 350 and variable amount of biotite. Occurrence of xenocrystc andalusite is also Lago reported from several outcrops. Franzoi Fila Facies Crosa Torrente 300 10 km S.S PERMIAN VALLE 350 N. 232 Granodioritic monzogranite Cacciano 1 cm 1 cm Medium to coarse grained monzogranitic granodiorite. Equigranular to S. NICOLAO 450 300 mildly inequigranular due to the presence of K-feldspar crystals with size Colle Rufino 400 400 vgrL Campalveno S.Liberata ranging from 0,5 to 2 cm, abundant plagioclase, quartz, around 15% biotite 12 km and rare amphibole. It shows faint magmatic foliation and growth of garnets E F 350 Cremosina Line 450 350 350 300 near to the contact with its metamorphic host rocks. Locally abundant mafic 400 microgranular enclaves.

400 Lower Valle Mosso Facies 400 14 km 350 Rongio PERMIAN

300 Forte 350

Maglione 350 Bozzone INTRUSIVE ROCKS OF THE MAFIC COMPLEX, IVREA-VERBANO ZONE 0 km Colle Bruciato 300 0 400 Mafic igneous rocks, undivided 33 Undifferentiated gabbroic rocks (mainly norite and amphibole gabbro) and 350 mcg associated ultramafite bodies, which belong to the different units of the 1 Capovilla southern Ivrea-Zone Mafic Complex. 1 cm 1 cm 400 Costa PERMIAN 2 km no v.e. Valle Mosso section VALLENZENGO Mombello 7km

400 300 Fig. 1: Granitic facies of the Valle Mosso pluton: Migliario 400 400 METAMORPHIC ROCKS OF THE STRONA-CENERI ZONE Selva Serie dei Laghi 350 (A) Lower Valle Mosso Facies: inequigranular monzogranite with pods MASSERANO 350 Volcanic rocks of the Sesia caldera (r) Miola Undifferentiated orthogneiss and paragneiss of granodioritic composition marked by increased plagioclase content; 350 Gallotto 300 Lower to medium amphibolite-facies metamorphic rocks that comprises Ronco Serie dei Laghi schist and gneiss (ogn) Upper Valle Mosso facies (vgrU)

Serralunga 350 ogn orthogneiss, quartzo-feldspathic paragneiss and minor micaschists. (B) Fila Facies: fine-grained equigranular Mu-bearing leucogranite; Rio CARBONIFEROUS Montaldo facies (vgrE) 350 Valle Mosso pluton 350 Dallimonti (C) Vaudano facies: monzogranite with a disequigranular texture given by 300 350 Ivrea-Verbano Zone N 400 cm sized K-feldspars set in a fine-grained Kfs - Qtz - Pl matrix; Vaudano facies (vgrP) S.S 350 Kinzigite formation paragneiss (pgn) N. 232 METAMORPHIC ROCKS OF THE IVREA-VERBANO ZONE Monte Bastia facies (vgrM) (D) Monte Bastia Facies: melanocratic porphyry characterized by Qtz ocelli Mafic Complex 5049000 300 5049000 Scale 1:15.000 300 and anhedral Pl - Kfs phenocrysts set in a very-fine grained Bt-rich matrix; Fila facies (vgrF) 300 Diorite 350 Undifferentiated paragneiss 0 300 600 900 1200 1500 m Lower Valle Mosso facies (vgrL) 400 Medium amphibolite-facies rocks mostly consisting on rusty-weathering, semi- (E) Montaldo Facies: equigranular coarse to medium grained monzogranite; Undivided gabbro (mcg) LESSONA 300 Ostola pelitic paragneiss and pelitic biotite-rich schist with less amount of leucosomes, 350 300 pgn Contour interval: 10 m Bozino 350 calc-silicate paragneiss, banded quartzo-feldspathic paragneiss and black- (F) Upper Valle Mosso Facies: pink granite with Kfs phenocrysts set in a UTM (Universal Transverse Mercator) Grid Zone 32 Nord (WGS84) weathering amphibolite. Locally these rocks are found at upper-amphibolite Fig. 2: Reconstructed cross-section of the Valle Mosso pluton, no vertical exaggeration. interlocking Qtz - Kfs - Pl matrix Torrente facies conditions showing diffuse migmatization. Reconstruction accounts for estimated tilting and fault offset. 433000 435000 437000 439000 441000 CARBONIFEROUS

A A’ B B’ Notes: B’’ Geological survey of the area was carried out at between June 2013 and NE W January 2016. SW NE SW E Montaldo Topographic base from the 1:10.000 vectorial CTR (Carte Tecniche Regionali) Cerruti Mucengo Rio dello M. Bastia Mad.na del Vaudano Alcinengo (elev. 547 m) Sabbione maps of the Servizio Cartografico Regione Piemonte, 1991. T. Strona Prapomero (elev. 532 m) Zoppo Buccio Piana (elev. 527 m) Map grid coordinates relate to Universal Transverse Mercator Projection, Pratrivero Falcero 750 750 750 T. Strona T. Ostola 750 Zone 32S 1984 World Geodetic System Datum. T. Strona T. Vallefredda T. Sessera pgn fAb fb vgrF vgrF vgrF vgrM 600 pgn vgrP vgrE Pray 600 600 vgrE 600 Shaded relief image derived from digital elevation model with 5-meter fAb vgrL Qt Qtu vgrL vgrU fq resolution using contours and elevation point from the topographic base. vgrE ogn r 450 Qt 450 450 Qt r 450 vgrF vgrF 300 300 300 300 References: vgrF [1] Zingg, A. (1983) Schweizerische Mineralogische und Petrographische 150 150 150 150 Mitteilungen 63, 361-392. [2] Handy, M. R., Babist, J.,Wagner, R., Rosenberg, C. L., & Konrad, M. (2005) 0 m 0 m 0 m Deformation mechanism, rheology and tectonics: From minerals to lithosphere: 0 m Geological society (pp. 249–276). London: Special Publications, Geological vgrU Society of London. No Vertical Exaggeration 0 300 600 900 1200 1500 m © Journal of Maps, 2017