Download pdf - Strontium isotopic composition of some recent basic volcanites of the Southern Tyrrhenian Sea and Sicily Channel

Contr. Mineral. and Petrol. 23, 157--172 (1969)

Strontium Isotopic Composition of Some Recent Basic Volcanites of the Southern Tyrrhenian Sea and Sicily Channel

F. BARBERI, S. BOlCSI, G. FEtCRAI~A, and F. INlVOCENTI

Department of Earth Sciences, University of Pisa, I taly

Received April 30, 1969

Abstract. The sTSr/S6Sr ratios have been determined on the volcanic rocks of Ustica, Linosa and Pantelleria Islands. The petrology of these islands is typical of volcanic products belonging to the Mkalic suite. The volcanites of Ustica and Linosa Islands are mainly represented by basic terms (alkMibasMts and hawaiites), with minor mugearitie and trachytic differentiates. In addition to MkMi-basMts and hawaiites, also some alkaline and perMkMine rocks of Pantelleria have been isotopicMly analysed. The sTSr/S6Sr ratios are consistent with a suberustM origin for all the volcanic products of these islands. Some differences in the sTSr/S6Sr ratios have been found and tentatively related to an inhomogeneous Rb/Sr distribution in the mantle source material. The genetic relationships of these rocks with some products of the recent Tyrrhenian volcanism are also briefly discussed.

In t roduct ion

I n recent years the s t u d y of the evolu t ion of the s t ron t ium isotopic composi t ion of m a g m a t i c rocks has p rov ided an useful means for the inves t iga t ion of petro- genet ic problems. The app l ica t ion of this me thod to the s t u d y of the Te r t i a ry and Qua t e rna ry volcanic rocks of I t a l y appea red of in~erest since the gene~ic i n t e rp re t a t i on of these volcani tes is st i l l m a t t e r of discussion ( B c I ~ , ]965; MA~INELLI, 1966).

The f irst s t u d y of the isotopic composi t ion of I t a l i a n volcani tes was per formed b y Hu~LEY et al. (1966). These au thors found STSr/S6Sr ra t ios of 0 .706--0.707 for t r achy t i c samples of I schia is land and 0.708--0.709 for some Vesuvius and Ph laegrean Fie lds lavas ; higher values were ob ta ined on lavas of the R o m a n province (Vico, Bracc iano and Laziale volcano). I n order to expla in the re la t ive ly high values and the cont inuous var ia t ions of 87Sr/S68r ra t io found on the potass ic l avas of centra l I t a l y , Hu~L~.Y et al. (1966) suggested for these volcani tes a genet ic process involving a refusion of anc ient crus ta l ma te r i a l and a mixing of the m a g m a so ob ta ined wi th subcrus ta l ma te r i a l of normM basal t ic composi t ion.

I n a recent work the presen t au thors (BARB]~m et al., 1967) discussed a set of 87Sr/S6Sr resul ts carr ied out on volcani tes of the Pon t ine islands, where different t ypes of rocks, such as t r achybasa l t s , phonoli tes , t r achy te s and rhyol i tes , occur.

The au thors conclusion was t h a t all the p roduc t s of this volcanism have been or ig ina ted f rom a common source mate r i a l ; in fact the in i t ia l svSr/S6Sr ra t ios were qui te homogeneous wi th a mean va lue of 0.7073. This f igure is in good agreement

11c Contr. Mineral. and Petrol., Vol. 23

158 F. ]3ARBERI, S. BORSI, G. FERRARA, and F. IN~OOENTI:

with the values obtained by HUlCLEu et al. (1966) on trachytes of Ischia island; this appears to be consistent with the analogous geological locations of Ischia and the Pontine islands, all of them being emplaced along the border of the Thyrrhenian trench. Moreover these sTSr/S6Sr ratios were substantially higher than those assumed to be typical of oceanic basalts while on the other hand they appeared lower than common values found in crustal materials. Two possible genesis of Pontine volcanites were envisaged; they could derive from a subcrustal magma contaminated with crustal material or directly by fusion of a deeper part of the crust.

A recent set of sTSr/SGSr ratio determinations on the Vesuvius and the Phlaegrean Fields lavas has been recently published by HOEFS and WEBEPOtIL (1968) ; their results are in agreement with those previously obtained by HU~LEY et al. (1966).

I t appears clear from this short review that the available STSr/S6Sr data are too scarce in order to give a conclusive genetic interpretation of recent Italian volcanism, taking also into account that these data deal with volcanic regions characterized by different geological conditions. Firstly it appeared necessary to collect information on Sr isotopic composition of the basic rocks of the mediterranean basin, that is the presumably closest representatives of the pr imary magma of this area. Therefore we have studied the basic, almost basaltic, rocks of those volcanic islands occurring in the southern Thyrrhenian sea and in the Sicily Channel (Ustica, Linosa and Pantelleria) which from the point of view of their geological setting and of their petrological characteristics satisfied the above conditions.

Geological Outline of Ustiea, Linosa and Pantelleria Islands

Island o/ Ustica

The geographical location of the island of Ustica is shown in Fig. 1. In the Fig. 2 the position of the island is related to the Tyrrhenian trench. I t is to be observed tha t Ustica is located within the southern margin of the trench where the sea floor is more than 2,000 meters deep.

The rocks constituting the island are entirely of volcanic origin; they can be distinguished into three different formations corresponding to three successive stages of volcanic activity: a) a basal platform of basic lavas deposited in a submarine environment (STuRIALE~ 1962 and 1963) ; b) two small strato-volcanoes emplaced at the top of the basal formation, which are composed of basic lavas and pyroclastic deposits containing also trachytic pumices; c) a cone entirely constituted of fine pyroclastic deposits.

On the basis of the relationships recognized between the volcanic formations and the marine terraces PICHLE~ (1968) assigned the basal formation to the Sicilian stage and the youngest pyroclastic deposits to the Milazzian stage. K/Ar age determinations have been carried out on two samples of hawaiites from the basal submarine volcanic formation. Only a limit (less than 1 MY) has been obtained due to the young ages of these samples and the relatively low K content.

Strontium Isotopic Composition of Some Recent Basic Volcanites

I ~ : ......... i -r !

I / /

I /,/ I :

39o_1~

]/ ..... I~tlsticQ

"-.. .......

......J

159

,:ii !:i I .................... ~ : i;:~ i~ !~ii.i... " ..............

::::i!!::., ~"~ii~'iil!;n.t;il.~:ria./

11 ~ 12 ~ 13 ~ l & ~ 15 ~ 16 ~ 1 ' /~

Fig. l. Location map of Ustica, Linosa and Pantelleria islands

Island8 o/ Linosa and Pantelleria

These two islands which arc located in the Sicilian Channel (Fig. 1) show close analogies from the point of view of their geologic positions: in fact both of them emerge from two alligned trenchs (Linosa Trench and Pantelleria Trench) which separate the African platform form the Sicilian one (SEGRE, 1960). Linosa is a small, roughly quadrangular shaped, island of 6.2 km 2 area; it is constituted of a series of pyroelastic cones produced during the oldest volcanic activity; these cones are bounded and protected against erosion by basaltic lava fields related to a subsequent volcanic activity.

The oldest pyroclastie deposits contain abundant xenoliths either of basaltic or highly differentiated rock types generally trachytes and phonolites (DI PAOLA, 1967). Also for Linosa island only a limit (less than 1 MY) was obtained for the K/Ar age of basMts.

With respect ot Linosa, Pantelleria exhibits a more complex volcanic structure resulting from several different eruptive processes which have produced either basic lavas (olivine basalts, hawaiites and trachyandesites) or acid volcanites

160 F. BARBERI, S. Bol~sI, G. FERtCARA, and F. I~OC~T::

"- . . .

. . . . , . . , . . '" "'"

, 0 ~ 2~

39 ~

/ " " . . * ~ . , ~ . J|I I . 'PONZ A : ". ..

. . . . . . . . . . "'-. i '" " " ' ISCHIA

I i v

K~, . , 3o , . 6.o

e S

" . .

"-.... , . . . . - . -.~.

" - . . . . . . . . .....

~":::..::::....i:

. . . . . , . . . - - ' "

'" "" " ' " " ' " ' " . . . . . . . �9 . - " i i 8 0 " " ' " ' 276 ' ! �9 ": '] "O . , , - ...;::~.-,:,.,~ ' , ,_, ....... . . . , " .........;/, " %~

|3 ~ 1/, ~

",...T 3. J"-..

1000 r n t s i $ o b a t h . . . . . 2 0 0 0 m t s i s o b a t h . . . . . . . . . . 3 0 0 0 - 3 4 0 0 m r s i s o b a t h I I I l l

Fig. 2. Map showing the position of Ustica island related to the Tyrrhenian trench and the location of dregged samples T 3 and Ta

~;i~ .."";:.,.....-

3 4 0 0 m , ; ~ o b ~ t h I[lUl

(quartz bearing sodatrachytes, sodarhyolites and pantcllerites). The basic rocks appear to be referable to two distinct periods of volcanic activity. The oldest one gave rise to few scoriaceous domes of basaltic composition. On a sample of this group of volcanites (Cala d'Alca) the K/At method has also been applied giving an age of 0.75 i 0.1 MY. The youngest basic rocks consists of scoriaceous domes and lava flow of basaltic, hawafitie and trachyandesitic composition.

The acid products occur either as lava domes or lava flows with rare inter- ealations of pumiceous layers; their composition ranges from quartz bearing sodatrachytes to sodarhyolites and pantellerites. The acid voleanites can be related to two periods of activity, separated by the emplacement of two successive ignimbritie units; the lower (K/Ar age less than 0.5 MY) has a quartz-soda- trachytic compositions while the upper one is sodarhyolitic. The first ignimbritie unit was followed by the development of a large ealdera in the central par t of the island (RITT~A~, 1967).

Petrology o/the Volcanite8 o/ U~tica, Linosa and Pantelleria Islands

The basic volcanites of Ustica island are represented mostly by hawaiites. Typical basaltic rocks are not abundant, occurring only in few lava flows in the southern part of the island and as intercalations in the pyroclastic products of the Costa

Stront imn Isotopic Composition of Some Recent Basic Volcanites

Table 1. Chemical analyses and C.I.P.W. norms o/ volcanic rocks o/ Ustica

161

U 3 1 U 2 5 U 2 4 U 1 6 U 9 U 3 U 2 U I O

SiO 2 49.80 48.04 47.55 49.05 52.08 49.99 53.58 59.42 A120 a 18.83 15.96 16.02 15.84 16.79 15.37 17.72 16.82 F%O 3 2.41 3.42 3.82 4.43 4.36 3.53 3.09 2.20 FeO 5.42 6.97 6.36 5.44 4.73 6.28 4.48 2.14 MnO 0.09 0.16 0.16 0.16 0.15 0.16 0.17 0.16 MgO 4.38 8.37 8.69 7.52 4.72 6.55 3.19 0.78 CaO 10.32 8.99 8.97 9.91 9.28 8.40 5.80 2.03 Na20 3.65 4.09 3.50 3.32 4.04 4.24 5.66 7.13 K20 1.20 0.94 0.95 1.06 1.12 0.93 2.10 3.58 TiO 2 1.50 1.79 1.75 1.57 1.40 1.49 0.99 0.50 P205 0.64 0.58 0.57 0.62 0.43 0.59 0.83 0.36 H20- 0.57 0.07 0.44 - - 0.20 0.62 0.73 0.45 L.I. 1.41 0.94 1.47 1.18 0.62 1.76 1.72 3.93

100.22 100.32 100.25 100.10 99.92 99.91 100.06 99.50

Q o r

ab an

ne

di WO

eI1

fs e l l

hy fs

ol { fo fa

mt il ap

. . . . 1.29 - - - - 0.01 7.09 5.55 5.61 6.26 6.62 5.49 12.41 21.15

30.87 28.33 29.21 27.08 34.17 35.86 47.66 60.30 31.46 22.42 25.20 25.19 24.38 20.17 16.75 3.33

- - 3.39 0.21 - - - - - - 0.11 - - 6.49 7.68 6.50 8.31 7.87 7.37 2.76 1.83 4.02 5.24 4.65 6.17 5.68 4.89 1.78 0.98 2.09 1.84 1.27 1.33 1.47 1.94 0.92 0.80 1.96 - - - - 5.30 6.07 2.60 - - 0.96 1.02 - - - - 1.14 1.58 1.03 - - 0.79 3.44 10.93 11.90 5.08 - - 6.18 4,39 - - 1.97 4.23 3.60 1.21 - - 2.69 2.65 - - 3.49 4.96 5.54 6.42 6.32 5.12 4.48 3.19 2.85 3.40 3.32 2.98 2.66 2.83 1.88 0.95 1.52 1.37 1.35 1.47 1.02 1.40 1.97 0.85

U 31 = Porphyrit ic basalt, Cala di S. Maria. U 25 and U 24 = Alkali basalts, between Faro and Torre. U 16 Alkali basalt , Costa del Fallo. U 9 =Hawai i t e , Guardia dei Turchi. U 3 = Itawaiite, Pun ta tramoll tana. U 2 Mugearite, Pun ta f ramontana. U 10 = Trachytic pumice.

dc l F a l l o v o l c a n o . B a s a l t i c r o c k s c o n s i s t of p h e n o c h r y s t s of p l ag ioc l a se (An 58-55)

a n d o l iv ine (Fo 15-20) w i t h a t h i n i d d i n g s i t i c r im , se t i n a g r o u n d m a s s w i t h a

s l i g h t l y v a r i a b l e d e g r e e of c r y s t a l l i z a t i o n a n d c o n t a i n i n g s m a l l l a t h s of p l ag ioc l a se

a n d g r a i n s of o l iv ine , c l i n o p y r o x e n e a n d o p a q u e o x i d e s . T h e m o s t c o m m o n r o c k

t y p e of t h e b a s a l s u b m a r i n e v o l c a n i t e s of U s t i e a is a p o r p h y r i t i c r o c k w i t h

a b u n d a n t z o n e d p l ag i oc l a s e ( A n 85-50) a n d sca rce o l iv ine p h e n o c h r y s t s , m ic ro -

p h e n o c h r y s t s of p l ag i oe l a s e ( A n 50) a n d t i t a n i f e r o u s a u g i t e ( 2 V F ~= 58 ~

CA y = 44~ T h e g r o u n d m a s s is r i ch in a d a r k g lass d u s t e d w i t h o p a q u e o x i d e

g r a n u l e s . T h e c h e m i c a l c o m p o s i t i o n of t h e s e s t r o n g l y p o r p h y r i t i c r o c k s is

o b v i o u s l y c h a r a c t e r i z e d b y h i g h v a l u e s of CaO a n d A1203 (see U 3 1 in T a b l e 1).

T h e h a w a i i t e s of U s t i c a a r e m i n e r a l o g i c a l l y s i m i l a r to t h e b a s a l t s ; t h e y a re

s l i g t h l y p o r p h y r i t i c in p lag ioc lase , o l i v ine a n d sca rce aug i t e . T h e s a m e m i n e r a l s

w i t h a p l ag ioc l a se less ca lc ic t h a n t h e p h e n o c h r y s t s o c c u r in t h e g r o u n d m a s s .

C h e m i c a l l y t h e s e r o c k s c a n be wel l d i s t i n g u i s h e d f r o m t h e b a s a l t s o n t h e bas i s

162 F. BARBERI, S. BORSI, G. FERBARA., and F. I~NOC]~TI:

of the lower MgO contents and the higher contents of alkahes (see U9, U3 in Table 1). A lava flow with a typical mugearitic composition has been found in the northern part of the island (U2, Table 1). I t consists of a fine grained rock with a marked fluidal texture containing mierophenochrysts of zoned plagioclase (An 50-30) and alkali feldspar and rare small granules of olivine. Finally must be recorded the occurrence of trachytic pumice within the pyroclastic deposits of Ustica.

The petrological features of the Ustica volcanites are typical of a differentiation series of a primary alkalibasalt magma (hawaiites-mugearites-trachytes). The primary alkali basalt magma gave rise only to few recent lava flows; the dif- ferentiate products, and among them the more basic hawaiitic terms, predominate in the outcrops.

The basic rocks of Linosa island show rather uniform chemical and petrographical features. They are mainly comprised of alkali basalts porphyritic in olivine, augite and labradorite-andesine plagioclase. The groundmass is holo- crystalline or hipocrystalline and consists of the same minerals found in the phenoehrysts and of opgque-oxides and apatite. The approximate modal composition is as follows; plagioclase 55, olivine 20, clinopyroxene 17, accessory minerals and glass 8. Alkaline differentiates have been found only as xenoliths in pyroclastic deposits. These differentiates are mainly represented by trachytic rocks with phenochrysts of anorthoelase, a feldspathoid of the sodalite group, scarce andesine, augite, hornblende, biotite and sometimes also olivine (DI PAOLA, 1967). In Table 2 nine new chemical analyses of Linosa volcanites (analyst G. M. DI PAOLA, University of Pisa) are reported. The chemical composition of the Linosa basic rocks is typical of the alkalic suite. Besides the alkali basalts representing the fundamental product of the volcanism also picritic basalts, enriched in both modal and normative olivine and hawalites occur. The strongly differentiated products manifest a distinct trend towards trachytes, with a low content in normative nepheline.

The basic volcanites of Pantelleria are well known from the papers of WASHING- TON (1914), I:~ITTMANN (1967) and I~OMANO (1968). They are mainly porphyritic rocks consisting of phenochrysts of olivine, labradorite-andesine plagioclase and titaniferous augite, set in a hypocrystalline groundmass of andesine, titaniferous augite, ilmenite, magnetite, apatite. Chemically these rocks must be considered as alkali basalts transitional to hawaiites; they have in fact a higher alkalies (particularly K20 ) and a lower MgO content compared with the normal alkali basalts (see Table 3). Among the basic rocks of Pantelleria island it is of interest to note the occurrence of a mugearitic (trachyandesitic) type. The petrology of Pantelleria acid volcanites has been treated in detail in the papers of CAI~MIC~A~L (1962), ]~OMANO (1968) and RITTMA~N (1967).

In conclusion the basic volcanites of Ustica, Linosa and Pantelleria islands exhibit petrographical features typical of alkali basalt and their differentiates, such as the constant presence of stable olivine phenoehrysts without any traces of reaction rim with the liquid. In several specimens the olivine is also present as a true groundmass mineral. Orthopyroxenes and subcaleic pyroxenes are missing, clinopyroxenes always showing optical properties of normal augitic,

Stront ium Isotopic Composition of Some Recent Basic Voleanites

Table 2. Chemical analyses a~M C.I.P.W. norms o/volcanic roc]cs o] Linosa

163

B 6 B 8 B 9 B 10 B 14 B 16 In 1K In 2A In 2x

SiO~ 45.95 46.55 49.10 49.08 45.75 49.60 59.17 56.78 56.45 AI~O 3 13.57 15.23 15.36 15.42 13.16 16.31 18.23 17.08 19.19 F % 0 a 2.16 2.78 2.23 1.45 5.43 0.71 1.63 3.33 2.41 FeO 8.45 8.05 8.39 8.93 7.08 8.87 1.42 2.28 1.62 )/InO 0.17 0.17 0.17 0.17 0.16 0.17 0.09 0.15 0.08 MgO 11.74 8.77 6.25 7.44 14.38 5.61 1.08 2.04 1.11 CaO 9.25 9.04 9.25 9.84 7.68 8.87 3.78 4.35 5.28 Na~O 3.55 3.87 3.94 4.04 3.06 4.44 7.00 6.68 6.74 K20 1.37 1.50 1.08 0.77 0.89 1.55 3.87 3.29 3.06 Ti0~ 2.10 2.33 2.15 1.67 1.60 2.05 0.92 0.87 1.05 P205 0.44 0.66 0.45 0.32 0.37 0.60 0.43 0.36 0.59 H20- 0.09 0.06 0.16 - - 0.06 0.16 0.46 0.77 0.66 L.I. 0.93 0.89 0.93 0.99 0.99 0.99 1.36 1.96 2.17

99.77 99.90 99.46 100.12 100.61 99.93 99.44 99.94 100.41

q . . . . . . . . .

or 8.09 8.86 6.38 4.55 5.26 9.16 22.86 19.44 18.08 ab 15.07 20.69 30.87 27.04 23.21 28.09 52.94 49.52 48.84 an 17.05 19.76 21.04 21.67 19.55 20.00 6.90 6.91 13.08 ne 8.10 6.52 1.33 3.86 1.45 5.13 3.39 3.78 4.42

wo 10.84 8.67 9.14 10.46 6.73 8.38 3.11 5.14 3.20 di en 7.34 5.71 5.25 5.93 5.14 4.29 2.69 4.26 2.76

fs 2.65 2.34 3.48 4.08 0.88 3.88 - - 0.23 - - wo . . . . . . 0.66 - - 0.67 ol ~ fo 15.34 11.30 7.22 8.82 21.48 6.78 - - 0.57 - -

[ fa 6.12 5.11 5.28 6.70 4.08 6.76 - - 0.03 - - m t 3.13 4.03 3.23 2.10 7.87 1.03 2.20 4.83 2.44 il 3.99 4.42 4.08 3.17 3.04 3.89 1.75 1.65 1.99 ap 1.04 1.56 1.07 0.76 0.88 1.42 1.02 0.85 1.40 hm . . . . . . 0.11 - - 0.73

B 6 Picritie basalt, Montagna Rossa. B 8 -- Alkali basalt, M. Biancarella. B 9 ~ Alkali basalt, Cala Mannarazzo. B 1 0 = A l k a l i basalt , Cala Ponente. B 14 -- Picritie basalt, Timpone. B 16 -- Hawaiite, Scalo Vecehio. In 1K, In 2A and In 2 x = x e n o l i t h s of t rachytic type in pyroelastics of Linosa.

s o m e t i m e s t i t a n i f e r o u s v a r i e t i e s . F u r t h e r m o r e t h e a l k a l i n e a f f i n i t y of t h e s e r o c k s

is c l ea r ly i l l u s t r a t e d b y t h e a lka l i - s i l i ca a n d a lka l i -A120s-SiO 2 d i a g r a m s (Figs. 3

a n d 4). I n t h e d i a g r a m s t h e e m p i r i c a l b o u n d a r i e s b e t w e e n t h e t ho l e i t i e , a lka l i c a n d

h i g h - a l u m i n i a b a s a l t s f ie lds a re r e p o r t e d as d r a w n b y K v h - o (1968). Al l t h e

a n a l y z e d s a m p l e s fa l l i n t h e a lka l i e field. T h e m ~ g m a t i e e v o l u t i o n of t h e t h r e e

i s l a n d s is a lso t y p i c a l of t h e a lka l i e su i t e , g i v i n g r ise to d i f f e r e n t i a t i o n ser ies

r a n g i n g f r o m a l k a l i b a s a l t t o t r a c h y t e s ( U s t i e a a n d L i n o s a ) or t o t r a e h y t e s ,

r h y o l i t e s a n d p a n t e l l e r i t e s ( P a n t e l l e r i a ) , w i t h h a w a i i t e s a n d m u g e a r i t e s as c o n s t a n t

i n t e r m e d i a t e m e m b e r s . H o w e v e r t h e d i f f e r e n t i a t i o n ser ies e x h i b i t a s o m e w h a t

d i f f e r e n t e v o l u t i o n p a r t i c u l a r l y in t h e i r o n e n r i c h m e n t t r e n d , as is c l ea r ly

i l l u s t r a t e d i n t h e A M F d i a g r a m (Fig. 5). T h e p o s i t i o n i n t h e d i a g r a m of t h e

U s t i e a a n d L i n o s a r e p r e s e n t a t i v e p o i n t s c l ea r ly i n d i c a t e s a s ingle f r a e t i o n a t i o n

t r e n d w i t h a low i r o n e n r i c h m e n t . T h i s f e a t u r e c a n be a s s u m e d as a n i n d i c a t i o n

164 F. BAlCBERI, S. BOI~SI, G. FEI~I~ARA, and F. I ~ o e E ~ T I :

Table 3. Chemical analyses and C.I.P. W. norm8 o] basic rocks o] PanteUeria

1 2 3 4 5 6 7 8 9 10

Si02 45.20 45.75 46.80 50.15 46.31 46.40 46.22 44.83 46.46 48.60 AlcOa 16.25 14.65 14.40 15.29 14.18 14.34 12.23 11.73 14.64 16.49 F%03 5.95 13.01 5.62 11.78 1.91 4.09 4.91 1.35 3.27 4.19 FeO 6.87 tr. 7.52 - - 11.76 8.22 7.71 11.79 9.11 7.40 MnO 0.13 0.13 0.15 0.18 0.23 0.25 - - 0.20 0.14 0.18 MgO 6.35 6.75 6.55 3.83 5.43 7.00 6.74 5.50 8.19 4.70 CaO 10.30 10.02 10.16 8.69 10.07 9.85 9.86 9.63 10.33 7.79 Na20 3.42 3.41 3.30 4.20 3.21 3.59 3.39 3.34 2.92 4.43 K~O 1.03 1.20 0.96 1.92 1.08 1.00 1.13 1.40 0.84 1.60 Ti02 3.47 3.48 3.39 2.97 3.94 4.54 5.68 6.88 3.01 3.16 P205 0.79 0.57 0.71 1.07 1.33 0.85 1.46 2.14 0.37 0.69 H ~ 0 - - - 0.34 - - n.d. - - 0.08 0.05 0.10 - - - - t t20+ - - - - - - n.d. 0.36 0.14 0.17 0.81 - - - - L.O.I. 0.76 0.78 0.83 . . . . . . .

100.52 100.09 100.39 100.08 99.81 100.35 99.55 99.70

Q - - - - - - 1.17 or 6.08 7.09 5.67 11.34 ab 25.58 28.84 27.91 35.52 an 25.95 21.13 21.65 17.20 ne 1.81 - - - - - -

wo 8.34 5.53 10.07 3.87 di en 6.52 4.78 7.37 3.35

fs 0.91 - - 1.74 - - en - - 9.67 2.92 6.18

hy fs - - - - 0.69 - -

{ f o 6.51 1.65 4.21 - - ol fa 1.00 - - 1.09 - -

m t 8.63 - - 8.15 - - il 6.59 0.28 6.44 0.39 tn - - - - - - 6.79 ap 1.87 1.35 1.68 2.54 h m - - 13.01 - - 11.78 pf - - 5.67 - -

6.40 6.12 6.67 8.34 5.00 9.45 27.17 28.30 28.82 28.30 24.63 35.11 21.09 20.02 14.73 12.79 24.46 20.57

- - 1 . 1 4 - - - - - - 1.14 9.78 5.57

16.85 18.81 19.54 17.22 6.40 3.60 2.90 1.58

2.17 - - 8.06 5.21

9.17 5.74 12.48 9.32 0.28 6.78 5.00 2.86

2.78 6.03 7.19 2.09 4.64 6.03 7.48 8.66 10.79 13.07 5.78 6.08

3.16 2.02 3.36 5.04 1.01 1.68

1 ~ Hawaii te - - Cuddia del Monte (Ro~A~o, 1968). 2 = Andesine b a s a l t - scorie M.S. Elmo (Ro~A~o, 1968). 3 -- Andesine basal t - - Campobel]o (I:~OMA~O, 1968). 4 = Trachyandesi te (mugearite) - - Le Balate (RoMA~o, 1968). 5 ~ A l k a l i basal t - - Costa Zeneti (includes also Cr2030.01; V~05 0.11; BaO and SrO 0.04;

S 0.06; C10.06; F 0.09) (ZIES, 1962). 6 ~ Alkali basal t - - Cuddia Ferle (includes also SO s 0.12; BaO 0.09; SrO 0.03) (WAsm~GTO~,

1914). 7 = Alkali basal t - - M.S. Elmo (WAsm~GTO~, 1914). 8 = Alkali basal t Foers tner Volcano (WAshinGTON, 1909). 9 = Alkali basalt , average of 28 analyses of Hawaii (MAcDonALD and KATSVRA, 1964).

10 = Hawaiite, average of 33 analyses of Hawaii (MAcDo:NALD and KATSUR.4, 1964).

of a t a l c - a l k a l i n e t e n d e n c y ( K v ~ o , 1968) f o r t h e v o l c a n i c se r i e s of t h e s e

i s l a n d s . O n t h e c o n t r a r y t h e t r e n d o b t a i n e d j o i n i n g t h e b a s i c r o c k s of

P a n t e l l e r i a ( a n a l y s e s f r o m T a b l e 3) w i t h t h e g r o u p of t r a c h y t e s , r h y o l i t e s a n d

p a n t e l l e r i t e s of t h e s a m e i s ] a n d ( a n a l y s e s f r o m CA~MIC~AEL, 1962, a n d ROM)~NO,

Strontium Isotopic Composition of Some Recent Basic Volcanites 165

+ USTICA o LINOSA

a PANTELLERIA

",~ FOERST NER

o + %

10--

o+

o o

~ o o + +

.o +o+

/

) S~0z

Fig. 3. A]kalh silica diagram for Ustica ~nd Linosa vo]canites and for basic rooks of Pantelleria.

The boundary lines between tholeiitic, high-alumina and alka]ic basa]ts fields are redrawn

~rom KuNo (1968)

2 0 -

18 -

16 ~ d

12

lO

18

d

12

10

/

,+

i l l

o

+

o + o o + a

l I

;) N a 2 0 + K 2 0

z~

o

%% o

z~

r i i 5 6 7

+ USTICA o LINOSA z~ PANTELLERIA

FOERSTNER

Si Oz= 47.5 -50.15

I I 1

Si02=45.0-47 .5

l i i i0 8 9

Fig. 4. Alkali-Al2Q-SiO 2 diagram for Ustica and Linosa volcanites and for basic rocks of Pantelleria. Boundary lines as drawn by Ku~o (1968)

1968) shows a remarkably higher iron enrichment. This trend is very similar to the one observed for the alkali-basalt differentiation series of the Hawafian islands (McDoz;A~D and KATSURA, 1964).

166 F. ]~ARBERI, S. BORSI, G. FERRAI~A, a n d F. INNOCENTI:

Fe 0 + Fe~ 0, (as Fe0)

+ USTICA o LtNOSA

PANTELLERIA

Na=O+K20 ~gO

Fig. 5. A-M-F diagram for Ustica, Linosa and Pantelleria volcanites. Dashed area repre- sents the field of Pantelleria acid rocks

The S%r/STSr Ratios of Basic u from Ustica, Linosa and Pantellcria Islands

Analytical Procedures

The chemical and isotopic analyses of Rb and Sr have been carried out following the s tandard procedures. Rb and Sr amounts were measured by isotope dilution techniques using an Atlas CI-I4 mass spectrometer equipped with an ion multi- plier; the uncer ta in ty in l~b and Sr determinations is • 2 % and i 1.5 % respec- tively. The isotopic compositions were measured on separate unspiked samples. The reproducibili ty of sTSr/S6Sr measures can be est imated from determinations carried out on a sea water s tandard and repeated during the progress of this work (Table 4).

Table 4

Dates of runs sTSr/S~Srmeas.

6. 5.1968 0.7090 12. 6. 1968 0.7085 24. 7.1968 0.7079 11.12. 1968 0.7078

Discussion o/Isotopic Results The data of the Rb and Sr contents and the isotopic results are listed in the Tables 5 - - 7 ; all the examined rocks show low initial sTSr/SGSr ratios very close to those commonly found for oceanic basalts (HEDGE, 1966; GAST, 1967).

However some slight variations can be observed within the groups of isotopic results obtained for each island.


I n the rocks of Us t i ea no signif icant var ia t ions can be observed in the sTSr/SGSr values of hawai i tes , mugear i tes and t r achy t e s (a sample of t r achy t i c pumice [U 10] y ie lded a ra t io STSr/S6Sr of 0.7029). Only two basal t ic samples f rom the same lava flow (U24 and U25) gave s l ight ly higher values (0.7055 and 0.7059 respect ively) . F r o m the po in t of view of the i r pe t rograph ica l and chemical character is t ics these two samples do no t differ f rom the other basa l t s s tudied; therefore i t seems diff icult to expla in the above d i sc repan t ra t ios as due to a con tamina t ion of the pa ren t a l magma, expeeia l ly t ak ing into account the re la t ive ly high s t ron t inm con ten t of these samples t h a t will require large amoun t s of con t aminan t mater ia l . These resul ts (perhaps excluding U24 and U25) are consis tent wi th the hypothes is t h a t all the p roduc ts of the Ust iea volcanism have been der ived f rom a common p a r e n t m a g m a of subcrus ta l origin, b y means of a d i f ferent ia t ion process pro- eeeding f rom basa l t s to t r achy t i e t ypes wi thou t involving any ass imi la t ion of crusta l mater ia ls .

Table 5. Rb, Sr data and Sr isotopic ratios o/ Ustica volcanites

Sample Rb Sr Rb/Sr K/Rb STRb s7Sr (ppm) (ppm) s6Sr s6Sr

U 30 Porphyritic basalt 35 976 0.036 277 0.10 0.7020 U 31 Porphyritic basalt 21 998 0.021 474 0.06 0.7016 U 24 Alkali basalt 2~9 884 0.022 394 0.07 0.7057 U 25 Alkali basalt 19 880 0.021 410 0.06 0.7055 U 16 Alkali basalt 21 895 0.023 419 0.07 0.7035 U 17 Alkali basalt dyke 24 863 0.028 395 0.08 0.7040 U 9 ~awaiite 23 582 0.039 404 0.12 0.7037 U 3 I-Iawaiite 12 659 0.018 643 0.05 0.7020 U 2 Muge~rite 46 1,026 0.045 380 0.13 0.7022 U 10 Trachytic pumice 64 338 0.19 464 0.54 0.7029 T 3 ~ 39 ~ 28' 5" N, 14 ~ 50' 5" E 4 . . . . 0.7026 T 4 39 ~ 17' N, 14 ~ 23' E 9l 366 0.27 245 0.71 0.7032

Non magnetic fraction.

I n Table 5 there are also r epor t ed the d a t a ob ta ined on two samples (T3 and T4) represent ing a po rphyr i t i c basa l t and a t r achyandes i t e respect ively , which have been d redged f rom the deep floor of the Tyr rhen i an sea (for thei r locat ion (see Fig. 2). The close s imi la r i ty of pe t rographic character is i t ies and of svSr/S6Sr ra t ios found be tween these samples and the corresponding types occur- r ing a t Ust ica i s land suggests a s imilar genesis.

The rocks of Linosa is land (Table 6) show a l i t t le more dispersed d i s t r ibu t ion of the i r S7Sr/S6Sr ra t io values compared with those of Ust ica. However mos t of t h e m are ve ry close to the mean va lue of 0.7042. The highest ra t ios values were ob ta ined on the samples B 8 (0.7060) and B I4 (0.7066) the l a t t e r represent ing a pier i t ic basal t .

The isotopic resul ts for several specimens of the Pan te l le r ia is land volcani tes are l is ted in Table 7. The mean value of the STSr/S6Sr ra t ios de te rmined on basic rocks (0.7037) is i n t e rmed ia t e be tween the means for Ust ica and Linosa. Moreover i t is to be no ted t h a t the ra t ios of the basic rocks subs tan t i a l ly agree wi th those of the acid products . Only two samples, a pante l le r i te and a basa l t show a higher rat io.

168 F. BARBERI, S. BORSI, G. FERRARA, and F. INNoe]~TI:

Table 6. Rb, Sr data and Sr isotopic ratios o/Linosa volcanites

Sample gb Sr Rb/Sr K/Rb STRb sTSr

(ppm) (ppm) s6Sr s6Sr

fl 9A Alkali basalt 16 451 0.035 560 0.10 0.7026 fi 13 Alkali basalt 22 453 0.048 432 0.14 0.7031 fl 10A Alkali basalt 11 404 0.027 581 0.08 0.7017 fl 10B Alkali basalt 14 451 0.031 500 0.09 0.7022 fl 4A Alkali basalt 5 642 0.008 1,140 0.02 0.7039 fl 7 Alkali basalt 29 617 0.047 365 0.16 0.7042 fl 8 Alkali basalt 28 621 0.045 443 0.13 0.7066 fi 14 Pieritie basalt 18 435 0.041 410 0.12 0.7060 fl 16 Hawaiite 22 464 0.047 584 0.14 0.7054 /~ 2A Hawaiite 30 493 0.061 483 0.18 0.7054

Table 7. Rb, Sr and Sr isotopic ratios o/ Pantelleria volcanites

Sample and location Rb Sr Rb/Sr K/Rb STRb svSr

(ppm) (ppm) s6Sr s6Sr

P l Alkali basalt (Cala dell'Alca) 13 431 0.030 615 0.09 0.7048 P 6 Alkali basalt (Monte S. Elmo) 19 615 0.031 505 0.09 0.7066 P 3 tIawaiite (Cuddia del Monte) 17 520 0.033 520 0.10 0.7023 P 4 tIawaiite (Campobello) 12 516 0.023 658 0.07 0.7046 P 5 Mugearite (Le Balate) 35 688 0.051 440 0.15 0.7047 P 10 Sodatrachyte (Montagna Grande) 64 183 0.449 520 1.0 0.7024 P 7 Sod~ryolite (Campobello) 173 4 43.25 237 119 0.7045 P 8 Pantellerite (Porto di Nika) 173 13 13.31 215 38 0.7027 P 9 Pantellerite (Cala Tramontana) 198 14 14.14 175 41 0.7067

t Ustica, Linosa and [ ~ Pantelleria i~lands

10 ~ l Ischia and Ponbine islands

8 ~l~ Recent igneous rocks IIII Of Tuscanl 9

4

700 702 704 700 708 710 712 714 715 S?Sr/85Sr

7~8

Fig. 6. Distribution plot of sTSr/S6Sr ratios of samples of Ustica, Linosa and Pantelleria (present work), of Pontine islands voleanites (BARBERI et al., 1967) and of rocks of the Tertiary and Quaternary magmatic province of Tus- cany (FEl%ttARA, 1968)

Fig. 6 shows a plot of the f requency di t r ibut ion of the sTSr/SGSr ratios obta ined

on all the studied samples. I t is clear t h a t most of the ratios range be tweea 0.702

and 0.704. This fact indicates t ha t the source mater ia l f rom which these rocks originated had the typical s t ron t ium isotopic composi t ion of uncon tamina ted subcrustal magmas. However several samples show slightly higher STSr/S6Sr ratios.

Strontium Isotopic Composition of Some Recent Basic Voleanites 169

87Sr~s6 S r

0 . 706

0 .704 -

0 . 702 -

C O

O O

D

O

O

0 . 7 0 0

O

I 500

O

Q

�9 L I N O S A

o U S T I C A

c~ P A N T E L L E R I A

[] D

4~0 600 K/~b

Fig. 7. Plot of K/Rb versus sTSr/S6Sr for Ustica, Linosa and Pantelleria volcanites

Since the emplacement ages of all the analyzed rocks are only slightly different and very young, the higher sTSr/S6Sr ratios can not be explained as due to a Rb decay which took place within differentiates melts characterized by high Rb/Sr ratios. Only for some alkaline volcanites of Pantelleria, characterized by high Rb/Sr ratios (samples P 7, P 8, P 9), a significant correction could be applied 1.

Other explanations are necessary. A first possibility is that the relative amounts of t~b and Sr are unhomogeneously distributed in the mantle. Therefore it could be possible to have two or more primary magmas bearing strontium with different isotopic compositions.

A second possibility is that the composition of the primary magma was everywhere uniform in the investigated area, and the observed higher ratios are to be considered a result of local interaction with crustal materials.

In the Fig. 7 the sTSr/SGSr ratios are related with K/Rb values. A correlation between these two parameters is to be expected if the variations of the sTSr/S6Sr ratios in a suite of volcanic rocks are due to contamination of suberustal magma with crustal material (L~ssI~G and C~TA~ZAI~O, 1964). In the ease of southern thyrrenian voleanites no correlation between sTSr/SaSr and K/Rb can be observed.

This fact, together with the lacking of any petrological indication of assimilation processes, seems to rule out the possibility of explaining the observed variations in the sTSr/S6Sr ratios by means of contamination.

In the Fig. 8 the Sr isotopic results are related with the Solidification Index (MgO'100/MgO-4-FeO+Fe203~-Na~O~-K20) for all the analyzed samples of Ustiea and Linosa and for the basic voleanites of Pantelleria. In this diagram no significant variations of STSr/S6Sr ratios with S.I. can be noted. A distinction seems possible between two groups of samples, each characterized by sTSr/S6Sr ratios practically constant in a range of variation of S.I. values. A first group shows sTSr/S~Sr values around 0.7055 and S.I. ranging from 12 to 45. The second group is characterized by lower STSr/S6Sr ratios (less than 0.704) and S.I. values comprised between 5 and 36.

1. Assuming an age of 0.5 lV[Y, the corrected 87Sr/S6Sr value of the sample P7 will be 0.7035.

12 Contr. Mineral. and Petrol., Vol. 23

170 F. BARBER][, S. BORSI, G. FERRARA, and F. INNOCE~TI:

87sr/__ ~86Sr

0.706-

0.704-

0.702-

0.700

�9 L INOSA o UST ICA [] PANTELLERIA

t t

5'0 40 30 20 lJO SI.

Fig. 8. Plot of Solidification Index (MgO-100/MgO--FeO+F%O3+Na20--K20) versus STSr/S~Sr for Ustiea, Linosa volcanites and for Pantelleria basic rocks

If the existence of any sensible contamination of subcrustal magma is excluded, these differences in the sTSr/S6Sr ratios can be explained only admitting an unhomogeneons distribution of Rb/Sr ratios in the mantle. This possibility has been already envisaged to explain the observed variations in Sr and Pb isotopic composition in the volcanic rocks of some oceanic islands (GAsT et al., 1964).

I t is to be noted that the different STSr/S6Sr ratios have been found in the volcanites of the same island (particularly Linosa and Pantelleria); this suggests a vertical variation of the t~b/Sr composition in the mantle.

The present data, together with those previously available from literature enable us to envisage the origin of some typical products of recent Italian volcanism.

Fig. 6 shows the plot of the distribution of the STSr/S6Sr ratios obtained in the present research compared with the previously published data on the Pontine islands volcanites (BAI~BEt~I et al., 1967), on Ischia island rocks (I-IvuL~u et al., 1966) and on rocks of the Tertiary and Quaternary magmatic province of Tuscany ( F ~ A ~ A , 1968); it is to be noted that an anatectie origin for the magmatic reeks of Tuscany has been recognized on the basis of petrographical and geo- chemical arguments (MARI~LLI, 1961; BARBEI~I et al., 1967). A crustal deriva- tion is also confirmed by the results of a Sr isotope study in progress on this subject (F~nRARA, 1968). The s7 St/S6 Sr ratios of the tuscan igneous reeks commonly range as high as 0.710 and are therefore strildngly higher than those obtained on the basic rocks of the islands of the southern Tyrrhenian sea and of the Sicily Channel. Between these two groups of values the ratios STSr/S6Sr of the Pontine volcanitcs occupy an intermediate position. At present it seems unlikely that these volcanites, characterized by higher ratios than the typical mediterranean basic reeks, have been originated from a mantle portion relatively enriched in Rb. In fact the subcrnstal magmas of the mediterranean area have I~b/Sr and STSr/S6Sr ratios quite similar to typical oceanic basalts; furthermore only slight variations in the isotopic composition of the pr imary magmas of this zone have been observed. The frequency distribution plot (Fig. 6) shows tha t the STSr/S6Sr ratios of the southern italian volcanites are distributed in a rather narrow range.


T h e i n t e r v e n t i o n of c rus ta l m a t e r i a l in t h e genesis of t h e P o n t i n e a n d I s ch i a

I s l ands v o l c a n i s m sti l l appea r s v e r y p robab le . This m a y h a v e occu r r ed e i the r

t h r o u g h c o n t a m i n a t i o n of subc rus t a l m a g m a w i t h u p p e r c rus ta l m a t e r i a l of h igh

STSr/SGSr r~t io or by d i r ec t d e r i v a t i o n of t h e m a g m a f r o m a lower c rus ta l r eg ion

w i t h l~b /S r a n d s~Sr/Sr ra t ios i n t e r m e d i a t e b e t w e e n those of u p p e r c rus ta l rocks

a n d t h e m a n t l e .

Acknowledgements. The authors are indebted with Drs. E. BARBIER and L. VILLAI~I for some specimens of Pantelleria island and with Dr. E. BO~ATTI for providing the two dredged samples of Southern Tyrrhenian Sea. Dr. H. SCUWARCZ kindly revised the English text. The work has been carried out with the financial support of the Consiglio Nazionale delle t~icerche and of the contract CNEN-CNR n ~ 115/1159/1427.

R e f e r e n c e s

BAR'BEI~I, F., S. BO~SI, G. Iq~ERRARA e F. I~OCE:NTI: Contribute alia conoscenza vulcano- logica e magmatologica delle Isole dell'Arcipelago Pontino. Mere. See. Geol. It. 4, 58]--606 (1967).

- - , F. I~OCE~TI e 1~. MAZZUOLI: Contribute alla conoscenza chimico-petrogrMica e magmatologica delle rocce intrusive, vuleaniche e filoniane del Campigliese (Toseana). Mere. Soc. Geol. It. 6, 643--681 (1967).

BoasI, S. : Contribute alla conoscenza dell'ets e della origine magmatica del vulcanismo dell'Isola di Capraia (Arcipelago toseano). Atti Soc. Toscana Sci. Nat. Mem., Ser. A 74, 232--243 (1967).

BURRL C. : Problemi petrochimici del vulcanismo italiano. Mere. Aec. Patav. SS.LL.AA., C1. Sci. Mat. Nat. 78, 109--133 (1966).

CAI~!VIICt~AEL, I. S. E.: Pantelleritic liquids and their phenocrysts. Mineral. Mag. 83, 86--113 (1962).

DI PAOLA, G. M. : Studio vuleanologico-petrografico dell'Isola di Linosa. Tesi di laurea in Sci. Geol. Pisa (1967).

FERRARA, G.: Rapporti fra la composizione isotopica dello Sr e i fenomeni anatettici nelle rocee della provincia anatettica toseana (Abstract). XXV Congr. See. It . Min. Petr. Napoli (196s).

GAST, P. W.: Isotope geochemistry of volcanic rocks. In: Basalts, the Poldervaart treatise on rocks of basaltic composition, eel. 1. New York-London-Sydney: John Wiley & Sons. 1967.

- - G . l~,. TILTO_X, and C. E. HEDGE: Isotopic composition of lead and strontium from Ascension and Gough Islands: Science 145, 1181--1185 (1964).

H~DGE, C. E. : Variations in radiogenic strontium found in volcanic rocks. J. Geophys. Res. 71, 6119--6126 (1966).

HOEFS, J., and K. H. WEI)EPGRL: Strontium isotope studies on young volcanic rocks from Germany and Italy. Contr. Mineral. and Petrol. 19, 328--338 (1968).

HVRL~Y, P. M., H. W. FAn~BAII~, and W. H. PINSO~, JR.: Rb-Sr isotopic evidence in the origin of potash-rich lavas of western Italy. Earth and Plan. Sci. Left. 1, 301--306 (1966).

Kv~,-o, I t . : Differentiation of basalt magma. In: Basalts: the Poldervaart treatise on rocks of basaltic composition, vol. 2. New u John Wiley & Sons. 1968.

MAcDonALD, G.A., and T. KATSV~A: Chemical composition of Hawaiian lavas. J. Petrol. 5, 82--133 (1964).

MARI~ELLr, G. : Genesi e classificazione delle vulcaniti recenti toscane. Atti Soc. Toscana Sci. l~'at., Ser. A 6S, 74--116 (1961).

- - Gen~se des magmas du voleanisme plio-qnaternaire des Apennins. Geol. Rundschan 57, 127--141 (1967).

PICKLER, g . : Zur Altersfrage des Vulkanismus des Aolischen Archipels und der Insel Ustica (Sizilien). Geol. Mitt. 7, 299--332 (1968).

12"

172 F. BARBERI et &l.: Strontium Isotopic Composition of Some l~ecent Basic Volcanites

I~ITTMA72~T, A.: Studio geovulcanico magmatologico dell'Isola di Pantelleria (with the collaboration of L. VILLARI, M. DIRE, and R. I~o~A~o): Riv. Mineraria Siciliana 106--108, 147--182 (1967).

ROMA~O, R. : New petrochemical data of volcanites from the Island of Pantelleria (Channel of Sicily) Geol. Rundschau 57, 3, 773--783 (1968).

SEGn]~, A. G.: Risultati preliminari dell'esplorazione ecometrica del Basso Tirreno. Rend. Accad. Naz. Lincei 15, 95--101 (1953).

- - Geologia. In: E. ZAVATTARI e coll., Biogeografia delle Isole Pel~gie. Rend. Accad. Naz. XL 11, Ser. 4, 115--162 (1960).

STV~IALE, C. : La formazione vulcanica submarina affiorante nell'Isola di Ustica. Boll. Ac. Gioenia Sci. Nat. Catania, Ser. IV 7, 24--34 (1962).

- - Pillows and hyaloclastites on the island of Ustica (Sicily). Bull. Voleanol. 25, 159--262 (1963).

ZI:ES, E. G. : A titaniferous Basalt from the island of Pantelleria. J. Petrol. 8, 177--180 (1962). WASI~I~GTO~, H. S. : The submarine eruption of 1831 and 1891 near Pantelleria. Am. J. Sei.

27, 131--150 (1909). - - The volcanoes and rocks of Pantelleria. J . Geol. 21, 653--669, 683--713; 22, 1--27

(1913--1914).

Dr. F. Bxanm~i Dept. of Earth Sciences University of Pisa Pisa, I taly