Coexisting calc-alkaline and ultrapotassic magmatism at Monti Ernici,Mid Latina Valley (Latium, central Italy)

New major and trace element data, and Sr–Nd–Pb-O isotopic ratios for volcanic mafic rocks outcropping at Monti
Ernici in the Mid Latina Valley (southern Latium) are reported, with the aim of investigating the nature and evolution of Plio-
Quaternary K-rich volcanism in Central Italy. Petrographical and geochemical studies allow us to identify mafic rocks ranging
from ultrapotassic (HKS) to shoshonitic (SHO), and calc-alkaline (CA), these last ones being identified for the first time. The CA
rocks exhibit the most primitive signatures for Sr, Nd, and Pb isotopes (87Sr/86Sr = 0.706326-0.706654; 143Nd/144Nd = 0.512388–
0.512361; 206Pb/204Pb = 18.944-18.940). The δ18O values are variable (δ18Ocpx from +5.75 to +7.08 ‰; and δ18Ool from +5.50 to
+6.23 ‰), suggesting interaction with carbonate wall rocks. Radiogenic isotope ratios and incompatible elements distribution have
several characteristic in common with equivalent rocks from Pontine Islands (Ventotene), Campania and Aeolian arc volcanoes.
Conversely, the HKS rocks closely resemble the ultrapotassic rocks from the Roman Province (87Sr/86Sr = 0.709679–0.711102;
δ18Ocpx from +6.27 to +7.08 ‰). The high ratios of LILE (Large Ion Lithophile Elements: Rb, Cs, Th, U, K, LREE) and HFSE
(High Field Strength Elements: Ta, Nb, Zr, Hf, Ti), and radiogenic isotope compositions of CA to HKS rocks indicate that all
suites contain subduction-related components, and suggest a N-MORB-type mantle source variably contaminated by hydrous fluids
and/or melts released by undergoing slabs, possibly during two distinct stages of metasomatism. The coexistence of ultra-alkaline
and sub-alkaline orogenic magmatism, combined with tectonic, geophysical and geological evidence, support the possibility that
the mantle beneath central-southern Italy (Ernici-Roccamonfina Province) was vertically zoned and produced different magma
suites during time.

Accordi, G., Carbone, F., Civitelli, G., Corda, L., De Rita, D., 63
Esu, D., Funiciello, R., Kotsakis, T., Mariotti, G., Sposato, A., 64
1986. Lithofacies map of Latium–Abruzzi and neighbouring ar- 65
eas. Geological map, 1:250,000. C.N.R., Progetto Finalizzato 66
Geodinamica. 67
Anderson, H. & Jackson, J., (1987): The deep seismicity of the 68
Tyrrhenian sea, Geophys. J. R. Astr. Soc., 91, 613-637 69
Ayuso, R.A., De Vivo, B., Rolandi, G., Seal, R.R., Paone, A. (1998): 70
Geochemical and isotopic (Nd - Pb - Sr - O) variations bear- 71
ing on the genesis of volcanic rocks from Vesuvius, Italy. J. 72
Volcanol. Geotherm. Res., 82, 53-78. 73
Baker, J., Peate, D.,Waight, T.,Meyzen, C. (2004): Pb isotopic anal- 74
ysis of standards and samples using a 207Pb–204Pb double spike 75
and thallium to correct for mass bias with a double focussing 76
MC-ICP-MS. Chem. Geol., 211, 275-303 77
Basilone, P. & Civetta, L. (1975): Datazione K/Ar dell’attività vul- 78
canica dei Monti Ernici (Latina). Rend. Soc. It. Mineral. Petrol., 79
31, 175-179. 80
Barbieri, M., Di Girolamo, P., Locardi, E., Lombardi, G. and 81
Stanzione, D. (1979): Petrology of the calc-alkaline volcanics 82
of the Parete 2 well (Campania, Italy). Period. Mineral., 48, 53- 83
74. 84
Castellarin, A., Colacicchi, R., Praturlon, A., Cantelli, C. (1982): 85
The Jurassic-Lower Pliocene history of the Ancona-Anzio line 86
(Central Italy). Mem. Soc. Geol. It., 47, 431-447 87
Civetta, L., Innocenti, F., Lirer, L., Manetti, P., Munno, R., 88
Peccerillo, A., Poli, G., Serri, G., (1979): Serie potassica ed 89
alta in potassio dei Monti Ernici (Lazio meridionale): consider- 90
azioni petrologiche e geochimiche. Rend. Soc.It. Miner. Petrol., 91
35, 227-249 92
Civetta, L.„ Innocenti F., Manetti P., Peccerillo A., Poli G. (1981): 93
Geochemical characteristics of potassic volcanics from Mt. 94
Ernici (Southern Latium , Italy). Contrib. Mineral. Petrol., 78, 95
37-47. 96
Conticelli, S. & Peccerillo, A. (1992): Petrology and geochemistry 97
of potassic and ultrapotassic volcanism in central Italy: petro- 98
genesis and inferences on the evolution of the mantle source. 99
Lithos, 28, 221-240. 100
Conticelli, S., D’Antonio M., Pinarelli, L., Civetta, L. (2002): 101
Source contamination and mantle heterogeneity in the gene- 102
sis of Italian potassic and ultrapotassic volcanic Rocks: Sr-Nd- 103
Pb Isotope data from Roman Province and Southern Tuscany. 104
Mineral. Petrol., 74, 189-222. 105
Cox, K.G., Hawkesworth, C.J., O’Nions, R.K., Appleton, J.D. 106
(1976): Isotopic evidence for the derivation of some Roman 107
region volcanics from anomalously enriched mantle. Contrib. 108
Mineral. Petrol., 56, 173-180. 109
Dallai, L., Freda, C., Gaeta, M. (2004): Oxygen isotope geochem- 110
istry of pyroclastic clinopyroxene monitors carbonate contribu- 111
tions to Roman-type ultrapotassic magmas. Contrib., Mineral., 112
Petrol., 148, 247-26. 113
D’Antonio, M., Tilton, G.R., Civetta, L. (1996): Petrogenesis 114
of Italian alkaline lavas deduced from Pb-Sr-Nd isotope relationships. 1 Earth Processes: reading the isotopic code.
2 Geophys. Monogr., 95, 253-267.
3 De Astis, G., Ventura, G., Vilardo, G. (2003): Geodynamic sig4
nificance of the Aeolian volcanism (Southern Tyrrhenian Sea,
5 Italy) in light of structural, seismological, and geochemical data.
6 Tectonics, 22, 4, 1040, doi:10.1029/2003TC001506.
7 De Astis, G., Piochi, M., Pappalardo, L. (2004): Procida Volcanic
8 History: new insights in the evolution of the Phlegraean
9 Volcanic District (Campania, Italy). Bull. Volcanol., 66, 622-
10 641.
11 De Astis, G., Kempton, P.D., Peccerillo, A., Wu, T.W. (2006):
12 Trace element and isotopic variations from Mt. Vulture to
13 Campanian volcanoes: constraints for slab detachment and man14
tle inflow beneath southern Italy. Contrib. Mineral. Petrol., DOI
15 10.1007/s00410-006-0062-y
16 Di Girolamo, P. (1978): Geotectonic settings ofMiocene Quaternary
17 volcanism in and around the eastern Tyrrhenian Sea border
18 (Italy) as deduced from major element geochemistry. Bull.
19 Volcanol., 41, 229-250.
20 Doglioni, C., Harabaglia, P., Merlini, S., Mongelli, F., Peccerillo,
21 A., Piromallo, C. (1999): Orogens and slabs vs. their direction
22 of subduction. Earth Sci. Review, 45,167-208.
23 Elburg, M., Vroon, P., van der Wagt, B., Tchalikian A. (2005): Sr
24 and Pb isotopic composition of five USGS glasses (BHVO-2G,
25 BIR-1G, BCR-2G, TB-1G, NKT-1G). Chem. Geol., 223, 196-
26 207.
27 Ellam, R.M., Hawkesworth, C.J.,Menzies,M.A., Rogers,W. (1989)
28 The volcanism of southern Italy: Role of subduction and re29
lationship between potassic and sodic alkaline magmatism. J.
30 Geophys. Res. 94, 4589-4601
31 Foley, S.F. (1992): Veins plus wall-rock melting mechanism in the
32 lithosphere and the origin of potassic alkaline magmas. Lithos,
33 28, 435-453.
34 Francalanci, L., Taylor, S.R., Mc Culloch, M.T., Woodhead, J.
35 (1993): Geochemical and isotopic variations in the calc-alkaline
36 rocks of Aeolian Arc (Southern Italy): constraints on the magma
37 genesis. Contrib. Mineral. Petrol. 113, 300-313.
38 Gaeta, M., Freda, C., Christensen, J.N., Dallai, L., Marra, F.,
39 Karner, D.B., Scarlato, P. (2006): Time-depend geochemistry of
40 clinopyroxene from Alban hills (central Italy): Clues to source
41 and evolution of ultrapotassic magmas. Lithos, 86, 330-346.
42 Gasperini, D., Blichert-Toft, J., Bosch, D., Del Moro, A., Macera,
43 P., Albarede, F., (2002): Upwelling of deep mantle material
44 through a plate window: evidence from the geochemistry of
45 Italian basaltic volcanics. J. Geophys. Res., 107, B12, 2367-
46 2385.
47 Giannetti, B. & Ellam, R. (1994): The primitive lavas of
48 Roccamonfina volcano, Roman Region, Italy: new constraints
49 on melting processes and source mineralogy. Contrib. Mineral.
50 Petrol., 116, 21-31.
51 Gill, J.B. (1981): Orogenic andesites and plate tectonics. Springer,
52 Berlin, 358 p.
53 Gvirtzman, Z. & Nur, A., (1999): The formation of Mount Etna as
54 the consequence of slab rollback. Nature, 401, 782-785.
55 Gvirtzman, Z. & Nur, A.,(2001): Residual topography, lithospheric
56 thickness, and sunken slabs in the central Mediterranean. Earth
57 Planet. Sci. Lett., 187, 117-130.
58 Hawkesworth, C.J & Vollmer, R. (1979): Crustal contamina59
tion versus enriched mantle 143Nd/144Nd and 87Sr/86Sr mantle:
60 143Nd/144Nd and 87Sr/86Sr evidence from the italian volcanics.
61 Contrib. Miner. Petrol., 69, 151-165. Hippolyte, J., Angelier, J., Roure, F. (1994): A major change re- 62
vealed by Quaternary stress patterns in the Southern Apennines, 63
Tectonophysics, 230, 199-210. 64
Hole, M.J., Graeme, R., Saunders, A.D., Storey, M. (1991): 65
Relation between alkalic volcanism and slab-window forma- 66
tion. Geology, 19, 657-660. 67
Irvine, T.N. & Baragar, W.R.A. (1971): A guide to chemical classi- 68
fication of common volcanic rocks. Can. J. Earth Sci., 8, 523- 69
548. 70
Keller, J. (1982): Mediterranean island arcs. in: “Andesites”. R.S. 71
Thorpe, ed. Wiley, Chichester, 307-325. 72
Kessel, R., Schmidt, M.W., Ulmer, P., Pettke, T. (2005): Trace ele- 73
ment signature of subduction-zone fluids, melts and supercriti- 74
cal liquids at 120-180 km depth. Nature, 437, 724-727. 75
Locardi, E. (1988): The origin of the Apenninic arc. Tectonophysics, 76
146, 105-123. 77
Lucente, F.P., Chiarabba, C., Cimini, G.B., Giardini, D. (1999): 78
Tomographic constraints on the geodynamic evolution of the 79
Italian region. J. Geophys. Res., 104, 20307-20327. 80
Mattey, D.P, Lowry, D., Macpherson, C.G (1994): Oxygen isotope 81
composition of mantle peridotite. Earth Planet. Sci. Lett., 128, 82
231-241. 83
Meletti, C., Patacca, E, Scandone, P. (2000): Construction of a seis- 84
motectonic model: the case of study. Pure Appl. Geophys., 157, 85
11-35. 86
Meloni, A., Alfonsi, L., Florindo, F., Sagnotti, L., Speranza, F., 87
Winkler, A. (1997): Neogene and Quaternari geodynamic evo- 88
lution of the Italian peninsula: the contribution of paleomagnetic 89
data. Ann. Geophys., 40, 705-727. 90
Melzer, S. & Foley, S.F. (2000): Phase relations and fractionation 91
sequences in potassic magma series modelled in the system 92
CaMgSi2O6-KAlSiO4-Mg2SiO4-F at 1 bar to 18 kbar. Contrib. 93
Mineral. Petrol., 138,186-197. 94
Metrich, N., Santacroce, R., Savelli, C. (1988): Ventotene, a potas- 95
sic Quaternary volcano in central Tyrrhenian Sea. Rend. Soc. It. 96
Mineral. Petrol., 43, 1195-1213. 97
Nakamura, N. (1974): Determinations of REE, Ba, Fe, Mg, Na 98
and K in carbonaceous and ordinary chondrites. Geochim. 99
Cosmochim. Acta, 38, 757-773. 100
Panza, G.F., (1984): Structure of the lithosphere-asthenosphere sys- 101
tem in the Mediterranean region. Ann. Geophys., 2, 137-138. 102
Panza, G.F., & Pontevivo, A. (2004): The Calabrian Arc: a detailed 103
structural model of the lithosphere-asthenosphere system. Rend. 104
Accad. Naz. Sci. dei XL, Mem. Sci. Fis. Nat., 28, 51-88. 105
Peccerillo, A. (1985): Roman Comagmatic Province (Central Italy): 106
evidence for subduction-related magma genesis. Geology, 13, 107
103-106. 108
Peccerillo, A. (1998): Relationships between ultrapotassic and 109
carbonate-rich volcanic rocks in central Italy: petrogenetic im- 110
plications and geodynamic significance. Lithos, 43, 267-279. 111
Peccerillo, A. (1999): Multiple mantle metasomatism in central- 112
southern Italy: geochemical effects, timing and geodynamic im- 113
plications. Geology, 27, 315-318. 114
Peccerillo, A. (2001): Geochemical similarities between the 115
Vesuvius, Phlegraean Fields and Stromboli volcanoes: petro- 116
genetic, geodynamic and volcanological implications. Miner. 117
Petrol., 73, 93-105. 118
Peccerillo, A. (2002): Plio-Quaternary magmatism in central- 119
southern Italy: a new classification scheme for volcanic 120
provinces and its geodynamic implications. in “Geological and 1 geodynamic evolution of the Apennines” R.M. Barchi, S. Cirilli,
2 G. Minelli, eds. Boll. Soc. Geol. It., Spec Vol, 1, 113-127.
3 Peccerillo, A. (2003): Plio-Quaternary magmatism in Italy.
4 Episodes, 26, 222-226.
5 Peccerillo, A. (2005): Plio-Quaternary volcanism in Italy. Petrology,
6 Geochemistry, Geodynamics. Springer Berlin Heidelberg New
7 York. 364 p.
8 Peccerillo, A., & Lustrino, M. (2005): Compositional variations
9 of the Plio-Quaternary magmatism in the circum-Tyrrhenian
10 area: deep- vs. shallow-mantle processes. in “Plates, plumes
11 and paradigms” G.R. Foulger, J.H. Natland, D.C. Presnall, D.L.
12 Anderson eds. Geol. Soc. Am., Spec. Paper, 388, 421-434.
13 Peccerillo, A., & Panza, G.F., (1999): Upper mantle domains be14
neath Central–Southern Italy: petrological, geochemical and
15 geophysical constraints. Pure Appl. Geophys., 156, 421-443.
16 Peccerillo, A., & Taylor, S.R. (1976): Geochemistry of Eocene calc17
alkaline volcanic rocks of the Kastamonu area, northern Turkey.
18 Contrib. Mineral. Petrol., 58, 63-81.
19 Peccerillo, A., Dallai, L., Frezzotti, M.L., Kempton, P. (2004): Sr–
20 Nd–Pb–O isotopic evidence for decreasing crustal contamina21
tion with ongoing magma evolution at Alicudi volcano (Aeolian
22 arc, Italy): implications for style of magma-crust interaction and
23 for mantle source compositions. Lithos, 78, 217-233.
24 Perini, G., Ponticelli, S., Francalanci, L., & Davidson, J.P. (2004):
25 Magmatological evolution and genesis of magmas from Vico
26 volcano, Central Italy: multiple differentiation pathways and
27 variable parental magmas. J. Petrol., 45, 139-182.
28 Piochi, M., Pappalardo, L., De Astis, G. (2004): Geochemical
29 and isotopical variation whitin the Campanian Comagmatic
30 province: implications on magma source composition. Annales
31 of Geophys., 47, 1485-1499
32 Piromallo, C. & Morelli, A. (2003): P wave tomography of the man33
tle under the Alpine-Mediterranean area. J. Geophys. Res., 108,
34 B2, 2065, doi: 10.1029/ 2002JB001757.
35 Rogers, N.,W., Hawkesworth, C.J., Parker, R.J.,Marsh, J.S. (1985):
36 The geochemistry of potassic lavas from Vulsini, central Italy,
37 and implications for mantle enrichment processes beneath the
38 Roman Region. Contrib. Mineral. Petrol., 90, 244-257.
39 Rottura, A., Del Moro, A., Pinarelli, L., Petrini, R., Peccerillo,
40 A., Caggianelli, A., Bargossi, G.M., Piccarreta, G. (1991):
41 Relationships between intermediate and acidic rocks in oro42
genic granitoid suites: petrological, geochemical and isotopic
43 (Sr, Nd, Pb) data from Capo Vaticano (Southern Calabria, Italy).
44 Chemical Geol., 92, 153-176.
45 Savelli, C. (1988): Late Oligocene to Recent episodes of magma46
tism in and around the Tyrrhenian Sea: implications for the pro47
cesses of opening in a young inter-arc basin of intra-orogenic
48 (Mediterranean) type. Tectonophysics, 146, 163-181.
49 Selvaggi, G. & Amato, A., (1992): Subcrustal earthquakes in the
50 Northern Apennines Italy: evidence for a still active subduction?
51 Geophys. Res. Lett., 19, 2127-2130.
52 Serri, G. (1990): Neogene-Quaternary magmatism of the Tyrrhenian
53 region: characterization of the magma sources and geodynamic
54 implications. Mem. Soc. Geol. It., 41, 219-242. Serri, G., Innocenti, F.,Mannetti, P. (1993): Geochemical and petro- 55
logical evidence of the subuction and delaminated Adriatic con- 56
tinental lithosphere in the genesis of the Neogene-Quaternay 57
magmatism of central Italy. Tectonophysics, 223, 117-147. 58
Sharp, Z.D. (1990): A laser-based microanalytical method for the 59
in situ determination of oxygen isotope ratios of silicates and 60
oxides. Geochim. Cosmochim. Acta, 54, 1353-1357. 61
Sharp, Z.D., (1995): Oxygen isotope geochemistry of the Al2SiO5 62
polymorphs. Am. J. Sci., 295, 1058-1076. 63
Stalder, R., Ulmer, P., Thompson, A.B., Günther, D. (2000): 64
Experimental approach to constrain second critical endpoints in 65
fluid/silicate systems: Near-solidus fluids and melts in the sys- 66
tem albite-water. Amer. Mineral., 85, 68-77. 67
Sun, S.S. & Mc Donough, W.F. (1989): Chemical and isotopic sys- 68
tematics of oceanic basalts: implications for mantle composition 69
and processes. in: “Magmatism in ocean basins” A.D. Saunders 70
& M.J. Norry, eds. Geol. Soc. London., Spec. Publ., 42, 313- 71
345. 72
Thorkelson, D.J. (1996): Subduction of diverging plates and the 73
principles of slab window formation. Tectonophysics, 255, 47- 74
63. 75
Trigila, R. & De Benedetti, A. (1993): Petrogenesis of Vesuvius his- 76
torical lavas constrained by Pearce element ratios analysis and 77
experimental phase equilibria. J. Volcanol. Geotherm. Res., 58, 78
315-343. 79
Turi, B. & Taylor, H.P. (1976): Oxygen isotope studies of potassic 80
volcanic rocks of the Roman Province, central Italy. Contrib. 81
Mineral. Petrol., 55, 1-31. 82
Turi, B., Taylor, H.P. & Ferrara, G. (1991): Comparisons of 18O/16O 83
and 87Sr/86Sr in volcanic rocks from the Pontine Islands, M. 84
Ernici and Campania with other areas in Italy. in “Stable Isotope 85
Geochemistry: A Tribute to Samuel Epstein”. H.P. Taylor, J.R. 86
O’Neil, I.R. Kaplan, eds. Geochem. Soc. Spec. Publ., 3, 307-324 87
Vollmer, R. (1989): On the origin of the Italian potassic magmas. A 88
discussion contribution. Chem. Geol., 74, 229-239. 89
Wendlandt, R.F. & Eggler, D.H. (1980a): The origins of potassic 90
magmas: 1.Melting relations in the systems KAlSiO4-Mg2SiO2 91
and KAlSiO4-MgO-SiO2-CO2 to 30 kilobars. Am. J. Sci., 280, 92
385-420. 93
Wendlandt, R.F. & Eggler, D.H. (1980b): The origins of potassic 94
magmas: 2. Stability of phlogopite in natural spinel lherzolite 95
an in the KAlSiO4-MgO-SiO2-H2O-CO2 at high pressures and 96
high temperatures. Am. J. Sci., 280, 421-458. 97
Wood, D.A., Joron, J.L., Treuil, M., Norry, M., Tarney, J. (1979): 98
Elemental and Sr isotope variations in basic lavas from Iceland 99
and the surrounding ocean floor. Contrib. Mineral. Petrol., 40, 100
319-339. 101
Wortel, M.J.R. & Spakman, W. (2000): Subduction and slab de- 102
tachment in theMediterranean-Carpathian region. Science, 290, 103
1910-1917. 104