Lipari obsidian is of excellent quality, black per colour, very shiny and sometimes perlitic

It is generally subaphyric and contains clinopyroxene micro-phenocrysts (10–50 m), almost always con synneusis with magnetite and olivine micro-phenocrysts (Acquafredda et al., 1999).

3.2. Sardinia: Caterva Arci

30 km 2 and located durante the comprensorio of the gulf of Oristano. The volcanic activity developed during two distinct cycles per the Pliocene and Pleistocene, and therefore it belongs onesto the latest volcanism in Sardinia. The magmatic products erupted during the second cycle, can be divided into four phases. The lavas erupted in the first phase were very rich sopra silica, and consisted mainly of rhyolites, either massive or perlitic-obsidianaceous. Dacites and andesites, trachytes and trachyrhyolites followed mediante chronological succession, until the last stages of volcanic activity, which were characterized by quiet eruptions of basaltic lava flows (Piras, 2002; Bigazzi et al., 2005).

The obsidian outcrops were described for the first time per the 19 th century by De La Marmora (1839–40). Subsequently, sopra the 1980s, several independent studies contributed preciso the characterization of the multiple Ammasso Arci obsidian outcrops. Unfortunately, the results of these studies are available only per brief conference papers (Francaviglia, 1986; Mackey and Warren 1983) or sopra an unpublished dissertation (Herold, 1986).

More recently, considering the geochemical features the obsidian of Caterva Arci, Tykot (2002) subdivided them into four groups, SA, SC, SB1 and SB2. The obsidian sampled near Lavabo Cannas and Uras are clustered within the SA group; those sampled near Pau, Perdas Urias and Sonnixeddu belong to the SC group; those sampled at Santa Maria Zuarbara and Marrubiu are mediante the SB1 and SB2 groups, respectively (Tykot, 2002; Nave et al., 2007; De Francesco et al., 2008). Coppia puro their geochemical similarity, SB1 and SB2 have been grouped under the name SB sopra the present study.

Mucchio Arci obsidian populations are characterized by large biotite micro-phenocrysts (50–200 ?m), abundant crystals of feldspar (plagioclase and alkali feldspar) 50 ?m per size, orthopyroxene, magnetite, monazite and ilmenite (Acquafredda et al., 1999).

3.3. Palmarola

Geochronological momento, obtained by fission-track analyses, indicate an age of 1.7±0.3 Tuttavia for obsidian from Montagna Settentrione (Bigazzi et al., 1971; Bigazzi and Radi, 1981). Con a recent rete informatica Tykot et al. (2005) provided verso detailed geochemical study of 80 samples, and were able puro distinguish three source localities: Striscia Vardella, the northern end of Striscia Vardella and Montagna Tramontana. However, given the small size of the island, this distinction can be considered irrelevant from an archaeological point of view.

Palmarola obsidian contains micro-phenocrysts of clinopyroxene (5–20 ?m) and biotite. It is generally black in colour, glassy, poorly shiny and semi-opaque (Acquafredda et al., 1999). However, verso small amount of highly transparent obsidian was found at Lingua Vardella by Tykot et al. (2005).

3.4 Pantelleria

90 km east of Cape Bon, Tunisia. Pantelleria is famous for its peralkaline rocks, and especially for its greenish obsidian enriched per sodium and iron, known as Pantellerite (Farfallina et al., 1998; Acquafredda et al., 1999). Pantelleria has verso bimodal distribution of magmatic products. Mafic lavas, exposed con the NW calcio d’angolo of the island, include transitional basalt and hawaiite (from

62 seniorblackpeoplemeet sito mobile to 72 wt.% SiO₂), prevail in the SE sector (White et al., 2009). K–Ar determinations of mafic lavas done on different basaltic units give ages of 118 ± 9, 83 ± 5 and

29 ka BP (Civetta et al., 1984). Ages determined on felsic volcanic rocks range from 324 ka BP onesto 4 ka BP (Fraschetta et al., 1984, 1988, 1998; Mahood and Hildreth, 1986). The volcanic history of the island is characterized by large explosive eruptions, some of which produced caldera collapses, alternating with periods dominated by less energetic eruptions (Fraschetta et al., 1998). The oldest caldera, named La Ava, is dated at 114 ka BP (Mahood and Hildreth, 1986); the youngest caldera, named the Chiesa caldera by Cornette et al. (1983) and the Cinque Denti caldera by Mahood and Hildreth (1983), is related sicuro the eruption of the Green Tuff (50 ka BP; Orsi and Sheridan, 1984). The more recent (post-50 ka) history of the island has been subdivided by Farfallina et al. (1998) into six sialic eruptive cycles, intercalated with basaltic eruptions. The Green Tuff is considered the first of these six cycles. All the others are dated at around 35–29, 22, 20–15, 14–12 and 10–4 ka BP, respectively (Civetta et al., 1998).