Geochemistry and stratigraphic correlations — Application to the investigation of geothermal and mineral resources of Tuscany, Italy: Contribution to the knowledge of the ore deposits of Tuscany, II

doi:10.1016/0009-2541(84)90141-4

Chemical Geology

Volume 43, Issues 1–2, February 1984, Pages 77-113

https://doi.org/10.1016/0009-2541(84)90141-4 Get rights and content

Abstract

Major-element geochemistry (364 analyses) is used to obtain quantitative information on the initial mineralogical composition and the depositional environment of Paleozoic, more or less metamorphic, rocks from Tuscany and Elba. Furthermore, this method can be used to improve stratigraphic correlations by comparing the chemical compositions of the metamorphic rocks and their possible non-metamorphic counterparts of known stratigraphic position. The stratigraphic units were divided into two sets. The first includes the units of known stratigraphic or tectonic position, taken as reference groups: Permian Red Porphyries, Carboniferous rocks, Buti Group l.s., Porphyritic Schists, Porphyroids, Lower Phyllites and metabasites from the Apuan Alps and Elba. The second set comprises the units of uncertain position: metapelites and metapsammites from outcrops, mines and boreholes from the Boccheggiano—Niccioleta area, Calamita Schists and metabasites associated with these two units, Micaschists, Gneisses and associated amphibolites.

The main results are:

1.
(1) The Porphyroids and Porphyritic Schists differ strongly from the Permian Red Porphyries, thus confirming that they belong to two different volcanic episodes.
2.
(2) All the reference units consist of shales, sandstones s.s. or graywackes, differing by their degree of maturity (increasing from the Lower Phyllites to the Buti Group and to the Carboniferous formations).
3.
(3) The Carboniferous rocks, the Buti Group and the Lower Phyllites have distinct chemical compositions.
4.
(4) The Boccheggiano Formation l.s. and the Calamita Schists are similar and include rocks chemically equivalent to the Lower Phyllites, the Buti Group and the Carboniferous formations.
5.
(5) The Micaschists and Gneisses derive from shales and graywackes respectively, and chemically recall the Lower Phyllites.
6.
(6) The metabasites from the Apuan Alps and from Niccioleta are “within-plate basalts”, whereas the amphibolites interlayered within the Micaschists and Gneisses seem “ocean-floor basalts”.

References (78)

G. Cavarretta et al.
Hydrothermal metamorphism in the Larderello Geothermal Field
Geothermics
(1980)
P.A. Floyd et al.
Magma type and tectonic setting discrimination using immobile elements
Earth Planet. Sci. Lett.
(1975)
K.J. Reutter et al.
Lithospheric split in the descending plate: observations from the Northern Appennines
Tectonophysics
(1980)
A.M. Ziegler et al.
Silurian continental distributions, paleogeography, climatology, and biogeography
E. Abbate et al.
Introduction to the geology of the Northern Apennines
L. Amodio-Morelli et al.
L'arco calabro—peloritano nell'orogenesi Appenninico—Maghrebide
Mem. Soc. Geol. Ital.
(1976)
M. Arnold
Analyse isotopique et origine du soufre des sulfures de Rio Marina
E. Azzaro et al.
Metamorfiti di basso e bassissimo stadio nel settore Monti Romani—Argentario (Lazio settentrionale, Toscana meridionale)
Period. Mineral.
(1975)
G. Bagnoli et al.
The Tuscan Paleozoic: a critical review
G. Bagnoli et al.
A tentative stratigraphic reconstruction of the Tuscan Paleozoic Basement
Mem. Soc. Geol. Ital.
(1979)

G. Bagnoli et al.

Segnalazione di una potente successione clastica di età probabilmente carbonifera nel basamento della Toscana Meridionale

Mem. Soc. Geol. Ital.

(1980)

F. Barberi et al.

Il complesso scistoso di Capo Calamita (Isola d'Elba)

Atti Soc. Toscana. Sci. Nat. Pisa, Mem., P.V.

(1967)

J.P. Bard et al.

Métamorphisme plurifacial et sens de variation du degré géothermique durant la tectogenèse polyphasée hercynienne dans la partie orientale de la zone axiale de la Montagne Noire (Massif du Caroux, Sud du Massif Central français)

Bull. Soc. Géol. Fr. (7e)

(1973)

S. Baudelot et al.

Caractéristique et âge des cinq cycles paléozoiques du Nord-Ouest de la Corse

Bull. Soc. Géol. Fr. (7e)

(1976)

G. Bertini et al.

Deep Exploration in Larderello Field: Sasso 22 Drilling Venture

M. Boccaletti et al.

Evoluzione dell'Appennino settentrionale secondo un nuovo modello strutturale

Mem. Soc. Geol. Ital.

(1980)

J. Bodechtel

Zur Genese der Eisenerze der Toskana und der Insel Elba

Neues Jahrb. Mineral., Abh.

(1965)

A. Boriani et al.

Caratteri, distribuzione ed età del metamorfismo prealpino nelle Alpi

Mem. Soc. Geol. Ital.

(1974)

L. Brigo

Mineralizzazioni e metallogenesi nell' area della Fillade quarzifera di Bressanone

Studi Trentini Sci. Nat.

(1971)

L. Carmignani et al.

Falde di ricoprimento erciniche nella Sardegna a Nord-Est del Campidano

Mem. Soc. Geol. Ital.

(1978)

L. Carmignani et al.

Structural evolution of the Apuane Alps: an example of continental margin deformation in the Northern Apennines, Italy

J. Geol.

(1978)

L. Carmignani et al.

Evoluzione tettonico—metamorfica del basamento ercinico della Nurra (Sardegna NW)

Mem. Soc. Geol. Ital.

(1979)

G. Cavarretta et al.

Formation of authigenic minerals and their use as indicators of physico-chemical parameters of the fluid in the Larderello—Travale geothermal field

Econ. Geol.

(1982)

L. Cayeux

Le Gothlandien du sondage de Danneville (Calvados) et son milieu générateur

N.D. Chatterjee et al.

Thermal stability and standard thermodynamic properties of synthetic 2M₁-muscovite, KAl₂[AlSi₃O₁₀(OH)₂]

Contrib. Mineral. Petrol.

(1974)

J. Cogné et al.

L'orogène cadomien

Géologie de l'Europe du Précambrien aux bassins sédimentaires post-hercyniens

Mém. Bur. Rech. Géol. Min. (B.R.G.M.)

(1980)

D.di Colbertaldo et al.

II giacimento ferrifero della Nurra nella Sardegna nord-occidentale

Atti Soc. Ital. Sci. Nat.

(1962)

F.H. Cramer

A palynostratigraphic model for atlantic Pangea during Silurian time

A. Dallegno et al.

Pyrite deposits of the Gavorrano area, Grosseto

Atti Soc. Toscana Sci. Nat. Mem., P.V.

(1979)

F.A. Decandia et al.

Evoluzione paleogeografica del margine appenninico nella Toscana a Sud dell' Arno

Mem. Soc. Geol. Ital.

(1980)

R. Déchomets

Particularités chimiques et minéralogiques de la série méta-évaporitique du gisement de pyrite de Niccioleta, Toscane, Italie

Bull. Soc. Géol. Fr. (7e)

(1983)

A. Del Moro et al.

RbSr and KAr ages on minerals at temperatures of 300°–400°C from deep wells in the Larderello geothermal field (Italy)

Contrib. Mineral. Petrol.

(1982)

M. Del Rio et al.

Acritarchi siluriani della successione paleozoica di Domusnovas (Sardegna Sud-occidentale)

Mem. Soc. Geol. Ital.

(1979)

Y. Deschamps

Contribution à l'étude des gisements à pyrite—hématite de Rio Marina (Ile d'Elbe, Italie) — Approche pétrographique, géochimique et structurale

Y. Deschamps et al.

Étude chimique des séries porteuses des minerais de fer d'Elbe, Italie

Y. Deschamps et al.

Le gisement de pyrite—hématite de Valle Giove (Rio Marina, Ile d'Elbe, Italie) (Contribution à l'étude des gisements de Toscane, I)

Schweiz. Mineral. Petrogr. Mitt.

(1983)

F. Dimanche

Les minerais de magnétite et les skarns du Ginevro (Ile d'Elbe, Italie)

Miner. Deposita

(1971)

P. Elter

3.a. Apennin septentrional

Cited by (34)

Episodic hydrothermal alteration recorded by microscale oxygen isotope analysis of white mica in the Larderello-Travale Geothermal Field, Italy
2020, Chemical Geology
Citation Excerpt :
The metamorphic basement is overlain by a Tectonic Wedges Complex (Fig. 1B), mainly composed of slices of Upper Triassic carbonate and evaporites, Triassic quartzite and phyllite metasiliciclastics (“Verrucano”), and metasediments of the Phyllitic-Quartzitic Complex (Pandeli et al., 2005). Above the Tectonic Wedge Complex are units of the Tuscan Nappe, commonly consisting from bottom to top of Upper Triassic shallow marine carbonate and evaporitic sequences, Jurassic limestone and Cenozoic siliciclastic intervals (Cavarretta et al., 1980; Puxeddu et al., 1984). The cover of the LTGF consists of Upper Jurassic–Eocene Ligurian flysch with minor ophiolite rocks, sub-Ligurian flysch and Neogene lacustrine and marine sediments (Bertini et al., 2006).
Microscale oxygen isotope analysis (¹⁸O/¹⁶O) of minerals can identify distinct events of fluid-rock interaction. This method is, however, still limited to a few major and accessory minerals of which most are anhydrous minerals. We present the systematic study of oxygen isotope distribution in white mica by Secondary Ion Mass Spectrometry (SIMS). Texturally and chemically distinct white mica populations in granitic and contact metamorphic rocks from the Larderello-Travale geothermal field (LTGF), Italy, record stages of magmatic crystallization, metamorphic-hydrothermal replacement and fluid-rock interaction. The large range in intra- and inter-grain white mica δ¹⁸O values between 1 and 14‰ reflects varying protoliths and degrees of fluid-mineral interaction at variable temperatures (180–450 °C present-day temperatures; p.d.T.). This variability reflects the large-scale circulation of both (1) magmatic, syn-intrusive to early contact metamorphic hydrothermal fluids with high-δ¹⁸O values, and (2) meteoric fluids with δ¹⁸O values of −7‰ during a post-intrusive, late hydrothermal stage.
Metasedimentary rocks from the upper reservoir contain distinct white mica populations occurring in close proximity (μm-scale), including detrital grains (δ¹⁸O = 12–14‰; high Na, low Mg), partially altered white mica (δ¹⁸O = 8–9‰) and late hydrothermal white mica (1–6‰; low Na, mid Mg). The late hydrothermal white mica has similar δ¹⁸O values to other secondary minerals and is in equilibrium with meteoric-dominated fluids with a δ¹⁸O of −6 to 0.5‰, which circulated in the late hydrothermal stage. Downhole towards the lower reservoir, white mica from two contact metamorphic micaschist samples shows either (1) homogeneous δ¹⁸O values of ca. 9‰ likely due to recrystallization in the contact metamorphic hydrothermal stage (T ca. 600 °C), or (2) a large spread in δ¹⁸O from 2 to 12‰ within and across grains of variable texture and chemistry in the host rock and a cross-cutting quartz-white mica vein (ca. 300 °C, present day temperature; hereafter p.d.T.). This contrasting δ¹⁸O signature of white mica is also recorded in granite cored at up to 4.6 km depth. The Carboli granite contains white mica with a homogeneous magmatic δ¹⁸O of 10 ± 0.6‰, whereas older granite samples from Radicondoli have magmatic to hydrothermal white micas that vary in δ¹⁸O from 4 to 10‰. A pronounced intra-grain δ¹⁸O variability of up to 6‰ occurs in white mica domains with higher Fe-Mg-Ti halos around inclusions of chloritized biotite, as a result of interaction with dominantly meteoric fluids that infiltrated to depths of at least 4.6 km. In the Porto Azzurro granite on Elba, Italy, altered white mica has δ¹⁸O values of 2.6‰ down from 10‰ in unaltered grains.
The distribution of oxygen isotope ratios in white mica is thus firstly a result of pervasive versus selective fluid alteration (at depth, sample and grain scale). Secondly, the actual preservation of these μm-scale variabilities indicates that volume diffusion is not detectable at microscale at p.d.T at or below 350 °C where most of the heterogeneous white mica is found. Selective, sample- and grain-scale fluid penetration occurs episodically and anisotropically, on micro- and megascale, along faults, fractures and cleavages, producing lower δ¹⁸O white mica at various times in zones of higher secondary permeability and active hydrothermal fluid circulation.
Evidence of Permian magmatism in the Alpi Apuane metamorphic complex (Northern Apennines, Italy): New hints for the geological evolution of the basement of the Adria plate
2018, Lithos
Citation Excerpt :
They show a distinct augen texture, with large magmatic phenocrysts of quartz (usually with magmatic embayment) and K-feldspar, in a fine-grained matrix formed by muscovite, quartz, and chlorite (Barberi and Giglia, 1965). Chemical data indicate a rhyolitic/dacitic composition for the volcanic protolith (e.g., Puxeddu et al., 1984). The age of these rocks has long been debated.
The occurrence of metavolcanic rocks within the Paleozoic basement of the Alpi Apuane metamorphic complex has been known since long time. Among them, some massive porphyritic tourmaline-bearing rocks cropping out in the southern sector of the Alpi Apuane present some distinctive and peculiar features, differing from the better known middle Ordovician metarhyolites of the “Porfiroidi e scisti porfirici” Fm. The porphyritic tourmaline-bearing rocks belong to the recently proposed Fornovolasco Metarhyolite Fm. They are granular to porphyritic, with phenocrysts of quartz (often with magmatic embayment), pseudomorphosed feldspars, and mica (both biotite and muscovite), in a groundmass formed by quartz, white mica, albite, and K-feldspar. Tourmaline (schorl-dravite in composition) is an abundant accessory mineral, in some cases forming cm-sized spots. The studied rocks plot into the rhyolite field of the Total Alkali vs Silica classification diagram. They show a peraluminous nature, having an Alumina Saturation Index ranging from 1.3 and 3.2. Their trace-element signature is that typical of highly evolved orogenic magmas. Laser ablation-ICP-MS U—Pb datings on zircon suggest a Permian crystallization age (weighted average ages of the four samples ranging from 292 and 271 Ma), thus relating these rocks to a post-Variscan magmatism. This new dating represents the very first evidence of a Permian magmatism in the pre-Triassic basement of the Northern Apennines. The potential relationships between Permian felsic magmatism and the ore genesis in the Alpi Apuane metamorphic complex are also discussed.
Basement provenance revealed by U–Pb detrital zircon ages: A tale of African and European heritage in Tuscany, Italy
2017, Lithos
Citation Excerpt :
The Porphyroids from the Apuan Alps (457 ± 3 Ma) are coeval with the Porphyroids (460 ± 3 Ma) and their erosional products (455–450 Ma) from Elba Island (Sirevaag et al., 2016). These data are in agreement with previous age estimates based on either U–Pb detrital zircon chronological data from Elba Island (Musumeci et al., 2011) or correlations with the mid–late Ordovician magmatic events of Sardinia, dated at 465 ± 1 Ma (Oggiano et al., 2010; Puxeddu et al., 1984). Indeed, a magmatic flare-up took place in the middle Ordovician at the northern margin of Gondwana and has been interpreted as an Andean-type arc.
A new data set of ca. 500 LA–ICP-MS U–Pb detrital zircon ages for six metasedimentary units from the Tuscan basement (Apuan Alps, Monti Pisani, Monticiano-Roccastrada), along with a precise SHRIMP U–Pb crystallization age of a metavolcanic unit (Apuan Alps) have been collected to determine their depositional ages and provenance. These results have been integrated with the recently published ca. 900 U–Pb detrital zircon ages from Elba Island to draw a complete picture of the Paleozoic journey of the Tuscan basement. A major change in the sources supplying sediments to the Tuscan basins is shown to occur during this journey. Detrital zircon ages of early Cambrian to middle Ordovician metasediments mirror those of coeval northern Africa sediments: most samples were sourced in western Africa, while one sample is derived material from central northern Africa. The Tuscan block was therefore located at the peri-Gondwana margin, close to central northern Africa. The prominent mid-Ordovician magmatic arc activity (ca. 460 Ma) at the northern Gondwana margin and its detritus, characterise the zircon age distribution of Ordovician and Silurian volcano-sedimentary rocks, that were therefore generated at the northernmost Gondwana margin during subduction and subsequent initial Paleotethys rifting. The Carboniferous–Permian metasediments are dominated by populations of Ordovician and Variscan-age zircons, with a minor occurrence of Neoarchean and Paleoproterozoic zircons that is best explained by recycling of European Neoproterozoic–Cambrian metasediments. In summary, the main sources supplying the Tuscan basins were located in northern Africa throughout Cambrian–Ordovician times, shifting to the volcanic arc active at the northern Gondwana margin during the middle Ordovician. During Variscan and post-Variscan times, detrital zircon sources were mostly located in European terrains, witnessing the shift of Tuscany from Africa to Europe.
From Gondwana to Europe: The journey of Elba Island (Italy) as recorded by U–Pb detrital zircon ages of Paleozoic metasedimentary rocks
2016, Gondwana Research
Elba Island, located midway between Corsica and mainland Italy, is a small but important fragment of the Adria Plate. It has a rich sedimentary record preserved in a stack of tectonic nappes of both continental margin and oceanic origin. Especially the detrital zircons in early Paleozoic to early Mesozoic metasedimentary rocks provide an archive of many important geological events in the island's history. Elba Island and Adria originated along the northern margin of Gondwana, but drifted north in Silurian times to become part of Europe. A large new dataset of LA-ICP-MS and SIMS U–Pb zircon ages allows us to trace this history. Three main stratigraphic units have been investigated. The oldest Porto Azzurro Unit was deposited in the early Cambrian and has zircon age distributions indicating a typical northern African provenance, most likely sourced from the Saharan Metacraton. The Ortano Unit has a simple, mostly unimodal Ordovician age distribution that is entirely dominated by metavolcanic rocks and their erosional products; a sample of the metavolcanic Ortano Porphyroids provided a SIMS U–Pb zircon age of 460 ± 3 Ma. This phase of intense volcanism is related to the subduction of the Rheic Ocean beneath Gondwana, terminating with initial rifting and subsequent opening of the Paleotethys. This also marks the onset of the separation of a range of European terranes, including Adria and future Elba Island, from Gondwana. The Permo-Triassic Monticiano–Roccastrada Unit is the first to show a European provenance with the appearance of large amounts of Variscan and late to post-Variscan detritus. The presence of Variscan detrital zircons in the Permo-Triassic sediments is unexpected, since a Variscan age signature is so far not well recorded in the Adria Plate. This dataset is the most comprehensive detrital zircon dataset so far available for the Adria Plate and documents Adria's close affinity to Africa in the Lower Paleozoic, as well as its initial rifting within an active continental margin setting during the Ordovician and its final separation and independent evolution since late Palaeozoic times.
Seismic slip recorded in tourmaline fault mirrors from Elba Island (Italy)
2016, Journal of Structural Geology
This paper reports the first example of fault mirrors developed in an unusual protolith, consisting of tourmaline crystals with interstitial goethite. The deformation mechanisms active in the fault zone have been investigated from the outcrop to the nanoscale, aiming to identify possible traces of frictional heating at seismic slip rate, as observed for other fault mirrors in different protoliths. The investigation revealed the superposition of two main deformational stages. The first was dominated by brittle processes and produced a cataclastic/ultracataclastic principal slip zone, a few mm thick; the second was associated with seismic slip and produced a sharp discontinuity (the principal slip surface) within the cataclastic/ultracataclastic zone. The mirror-like coating, a few microns thick, occurs on the principal slip surface, and is characterized by 1) absence of interstitial goethite; 2) occurrence of truncated tourmaline crystals; 3) highly variable grain size, from 200 μm to 200 nm; 4) tourmaline close packing with interlobate grain boundaries, and 5) tourmaline random crystallographic orientation.
Micro and nanostructural investigations indicate the occurrence of thermally-activated processes, involving both interstitial goethite and tourmaline. In particular, close to the principal slip surface, goethite is completely decomposed, and produced an amorphous porous material, with local topotactic recrystallization of hematite. Tourmaline clasts are typically characterized by strongly lobate boundaries, indicative of reaction and partial decomposition at grain boundaries. TEM observations revealed the occurrence of tourmaline nanograins, a few tens of nm in size, characterized by rounded shape and fading amorphous boundaries, that cannot be obtained by brittle processes. Lastly, the peculiar interlobate microstructure of the mirror surface is interpreted as the result of grain boundary recrystallization processes taking place by deformation at high-T conditions. Our results show that tourmaline fault mirrors recorded localized high-T processes triggered by frictional heating and can be therefore considered as reliable traces of ancient earthquakes.
Unravelling the complex interaction between mantle and crustal magmas encoded in the lavas of San Vincenzo (Tuscany, Italy). Part I: Petrography and Thermobarometry
2016, Lithos
The San Vincenzo Volcanic Complex was emplaced ~ 4.4 Ma. ago and consists of cordierite-bearing lavas which are the result of a complex interaction between mantle-derived and crustal anatectic magmas. The lavas are mostly characterized by porphyritic, glassy peraluminous rhyolites hosting variable contents of magmatic enclaves (clinopyroxene-bearing latites and amphibole-bearing clinopyroxene crystal mushes), sialic and ultramafic cognates (syenogranites, anorthosites, cordierite–biotite and pyroxenite inclusions), and crustal rocks (sillimanite–cordierite xenoliths, cordierite and biotite xenocrysts) of centimetric-to-millimetric size.
Mineral chemistry shows large variations as well. Plagioclase and sanidine are represented respectively by An_21–79Or_1–13 and An_≤ 1Or_57–77. Cordierite has a Mg# of 51–78%, while garnet shows almandine compositions with low CaO (≤ 2 wt.%) and variable MnO contents (1–5 wt.%). Clinopyroxene indicates large ranges of Mg# (68–92%) and Al₂O₃ (0.5–6.3 wt.%), and relatively high CaO contents (up to 24 wt.%); orthopyroxene shows both ferroan enstatite (Mg# = 60–78%) and magnesian ferrosilite (Mg# = 39–44%) compositions; whereas amphibole shows only Mg-rich calcic compositions. On the basis of textural characteristics, as well as Ti and X_Mg variations, we have identified six different types of biotite associated with oxide minerals such as ilmenite and spinels of both aluminium (Al > 1 in Y site) and iron (Fe > 1 in Y site) subgroups.
Compositional/textural relationships indicate crystallization at both equilibrium and disequilibrium conditions. Minerals with euhedral habits and homogeneous compositions usually occur in the same thin sections of partly-equilibrated crustal xenoliths (and xenocrysts) and zones of “active” mixing between mantle-derived and crustal magmas characterized by “needle-like” and skeletal microlites, and subhedral microphenocrysts of amphibole and biotite. These hybrid-mixed features, as well as the occurrence of calcic amphibole, garnet and magnetite, are exclusive to lavas cropping out in the northern sector of the volcanic complex (i.e. Acqua Calda Quarry). By contrast, the rhyolites in the southern area (i.e. Rozze Valley) mostly show mingled textures characterized by “coherent” globular blobs of mantle-derived magma (up to 15 cm in size) that did not efficiently homogenize with the rhyolite.
To determine the crystallization depths and physico-chemical conditions of the San Vincenzo magmatic feeding system, we applied some thermobarometers to single phases (amphibole and melt inclusions) or petrographic domains (sillimanite–cordierite xenoliths, syenogranites and anorthosites, piroxenites) showing crystallization at equilibrium conditions. In the framework of the estimated conditions, we used H₂O–CO₂ solubility, viscometric and densimetric models to obtain additional constraints on sub-volcanic processes.
The overall results suggest that the thermal interaction of a hot mantle-derived magma (~ 1100 °C) with the Tuscan crust (≤ 700 °C) occurred at the MOHO transition (~ 24 km). This interaction determined (i) partial melting of the lower-crust siliciclastic rocks, (ii) migration of the anatectic magma to shallower levels and (iii) formation of a deep storage region (16–24 km) filled with mantle-derived magma. In the deep reservoir, the mantle-derived magma evolved at conditions of 900–1010 °C, H₂O_melt 5.2–8.6 wt.% and + 2 ≤ ΔNNO ≤ + 4 through assimilation of carbonate–evaporite metasediments and fractionation of clinopyroxene (± plagioclase ± ferroan enstatite ± biotite) to form ultramafic and mafic crystal mushes and cumulates. The overlying siliciclastic rocks underwent partial melting at 710–850 °C (H₂O_melt ≤ 4 wt.%) leading to the genesis of a second reservoir filled with anatectic magma at depths of 8–17 km. Locally, the T–H₂O_melt conditions in the shallower reservoir were as high as 920 °C and ~ 5 wt.%, when the mantle-derived magma was injected into the rhyolite magma to form the mingled lavas which were afterwards erupted in the Rozze Valley area. The hybridization of the rhyolites occurred at 870–910 °C (H₂O_melt = 5–7 wt.%), suggesting that the Acqua Calda Quarry lavas were the last to be erupted.

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^☆: This investigation was supported by the C.N.R. (Italy) through a “Bilateral Project” and by the C.N.R.S. (France) through the A.T.P. “Formation et distribution des gisements” (Contrat D2842 — “Géochimie du Verrucano supérieur et du Calcare cavernoso. Application à la province métallogénique toscane occidentale”).

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Research paperGeochemistry and stratigraphic correlations — Application to the investigation of geothermal and mineral resources of Tuscany, Italy: Contribution to the knowledge of the ore deposits of Tuscany, II☆

Abstract

Geothermics

Earth Planet. Sci. Lett.

Tectonophysics

Introduction to the geology of the Northern Apennines

L'arco calabro—peloritano nell'orogenesi Appenninico—Maghrebide

Mem. Soc. Geol. Ital.

Analyse isotopique et origine du soufre des sulfures de Rio Marina

Metamorfiti di basso e bassissimo stadio nel settore Monti Romani—Argentario (Lazio settentrionale, Toscana meridionale)

Period. Mineral.

The Tuscan Paleozoic: a critical review

A tentative stratigraphic reconstruction of the Tuscan Paleozoic Basement

Mem. Soc. Geol. Ital.

Segnalazione di una potente successione clastica di età probabilmente carbonifera nel basamento della Toscana Meridionale

Mem. Soc. Geol. Ital.

Il complesso scistoso di Capo Calamita (Isola d'Elba)

Atti Soc. Toscana. Sci. Nat. Pisa, Mem., P.V.

Métamorphisme plurifacial et sens de variation du degré géothermique durant la tectogenèse polyphasée hercynienne dans la partie orientale de la zone axiale de la Montagne Noire (Massif du Caroux, Sud du Massif Central français)

Bull. Soc. Géol. Fr. (7e)

Caractéristique et âge des cinq cycles paléozoiques du Nord-Ouest de la Corse

Bull. Soc. Géol. Fr. (7e)

Deep Exploration in Larderello Field: Sasso 22 Drilling Venture

Evoluzione dell'Appennino settentrionale secondo un nuovo modello strutturale

Mem. Soc. Geol. Ital.

Zur Genese der Eisenerze der Toskana und der Insel Elba

Neues Jahrb. Mineral., Abh.

Caratteri, distribuzione ed età del metamorfismo prealpino nelle Alpi

Mem. Soc. Geol. Ital.

Mineralizzazioni e metallogenesi nell' area della Fillade quarzifera di Bressanone

Studi Trentini Sci. Nat.

Falde di ricoprimento erciniche nella Sardegna a Nord-Est del Campidano

Mem. Soc. Geol. Ital.

Structural evolution of the Apuane Alps: an example of continental margin deformation in the Northern Apennines, Italy

J. Geol.

Evoluzione tettonico—metamorfica del basamento ercinico della Nurra (Sardegna NW)

Mem. Soc. Geol. Ital.

Formation of authigenic minerals and their use as indicators of physico-chemical parameters of the fluid in the Larderello—Travale geothermal field

Econ. Geol.

Le Gothlandien du sondage de Danneville (Calvados) et son milieu générateur

Thermal stability and standard thermodynamic properties of synthetic 2M1-muscovite, KAl2[AlSi3O10(OH)2]

Contrib. Mineral. Petrol.

L'orogène cadomien

Géologie de l'Europe du Précambrien aux bassins sédimentaires post-hercyniens

Mém. Bur. Rech. Géol. Min. (B.R.G.M.)

II giacimento ferrifero della Nurra nella Sardegna nord-occidentale

Atti Soc. Ital. Sci. Nat.

A palynostratigraphic model for atlantic Pangea during Silurian time

Pyrite deposits of the Gavorrano area, Grosseto

Atti Soc. Toscana Sci. Nat. Mem., P.V.

Evoluzione paleogeografica del margine appenninico nella Toscana a Sud dell' Arno

Mem. Soc. Geol. Ital.

Particularités chimiques et minéralogiques de la série méta-évaporitique du gisement de pyrite de Niccioleta, Toscane, Italie

Bull. Soc. Géol. Fr. (7e)

RbSr and KAr ages on minerals at temperatures of 300°–400°C from deep wells in the Larderello geothermal field (Italy)

Contrib. Mineral. Petrol.

Acritarchi siluriani della successione paleozoica di Domusnovas (Sardegna Sud-occidentale)

Mem. Soc. Geol. Ital.

Contribution à l'étude des gisements à pyrite—hématite de Rio Marina (Ile d'Elbe, Italie) — Approche pétrographique, géochimique et structurale

Étude chimique des séries porteuses des minerais de fer d'Elbe, Italie

Le gisement de pyrite—hématite de Valle Giove (Rio Marina, Ile d'Elbe, Italie) (Contribution à l'étude des gisements de Toscane, I)

Schweiz. Mineral. Petrogr. Mitt.

Les minerais de magnétite et les skarns du Ginevro (Ile d'Elbe, Italie)

Miner. Deposita

3.a. Apennin septentrional

Research paper
Geochemistry and stratigraphic correlations — Application to the investigation of geothermal and mineral resources of Tuscany, Italy: Contribution to the knowledge of the ore deposits of Tuscany, II☆

Thermal stability and standard thermodynamic properties of synthetic 2M₁-muscovite, KAl₂[AlSi₃O₁₀(OH)₂]