Mesozoic volcanics of western sicily

Abstract

ZusammenfassungDie mesozoischen Laven und kleineren Intrusionen innerhalb der Schuppen yon Westsizilien besitzen folgende Charakteristika: 1. Die Laven innerhalb der triassischen Mufara-Formation im Norden sind zerbrochen zu Fragmenten, die unabh/ingig voneinander innerhalb der umgebenden inkompetenten Schichten rotiert wurden. Dieses ist fiir die magmatischen Gesteine der inneren (n6rdli-cheren) Oberschiebungseinheiten typisch. AbstractThe Mesozoic lavas and minor intrusions in the thrust sheets of western Sicily have the following characteristics: I. The lavas in the Triassic Mufara Formation in the north were broken into fragments which rotated independently within the incompetent strata that enclose them. This behavior is characteristic of igneous rocks found within the more internal (northerly) thrust units. 2. The Jurassic lavas in the more external (southerly) units have consistent directions which agree with those of the Ammonitico Rosso limestones in the same zone and lie about 30 ~ clockwise from those of coeval autochthonous formations in Tunisia. SCHULr presumed Cretaceous directions from Custonaci on the north coast (similar to those found in the Cretaceous Scaglia Rossa at Terrasini to the east by CHANNEL et al., 1980) are rotated still more (140 ~ with respect to those of the autochthonous Iblean platform of SE Sicily. These differences are believed to reflect rotation of the thrust R6sum6Leg laves et leg instrusions mineures m6sozoiques pr6sentes dang leg roches charri6es de la Sicile occidentale montrent leg caract6ristiques suivantes:1. Leg laves intercal6es dang la Formation de Mufara d'gtge triasique ont 6t6 morcel6es en fragments qui ont subi des rotations ind~pendantes dang leg marnes incomp6tentes qui leg enrobent. Ce comportement est typique des roches ign6es qui se trouvent dang les unit~s charri~es de la zone plus interne (septentrionale).2. Leg laves jurassiques des unit~s plus externes (m~ridionales) poss~dent des directions d'aimantation qui accordenz avec celles des calcaires de l'ammonitico rosso de la m~me zone externe qui d~vi~es d'environ 30 ~ vers la droite par rapport aux roches de m~me f~ge de la Tunisie. Leg directions, dites cr~tac~es de Schult, de la r6gion de Custonaci sur la c6te septentrionale (qui concordent bien avec celles trouv6es par CHANNELL et al. (1980) & Terrasini) diff+rent encore plus, avec une rotation de 140 ~ par rapport fi la plateforme autochtone d'Iblei (Sicile) SE). Ces diffOrences sont interpr6t6es comme refl6tant la rotation des nappes charri6es au cours du transport tectonique durant le Cenozo~que, la zone interne ayant subi une rotation plus intense.3. Toutes les roches ign+es sont fortement altOr6es; en gOn6ral on ne peut pas identifier les minOraux originels. L'abondance relative de certains des 616ments non-mobiles (Ti, Sr, Y) suggOrent une origine intracratonique. KpaTuoe eo~ep~aHneMe3030~crne naabi ~ He60abLuae !4HTpy3!4!4 BHyTp!4 qeLuyfi 3arIa~Ho~ C!4tlHYlH!4 xapaKxepH3yK)TC~ cJIe~yl~3ttt!4Mrl Oco6eHHOCT~MH:1. 5IaBbt BHyTpH rpriaccoaoi~ d...

The Calabrian Orocline: buckling of a previously more linear orogen

“…Subsequent palaeomagnetic studies (Gattacceca & Speranza 2002;Rosenbaum & Lister 2004;Speranza et al 1998Speranza et al , 1999Speranza et al , 2003 have served to confirm the results of the early palaeomagnetic studies. Rotations attributable to landslides have, at least locally, significantly complicated the story (Catalano et al 1984;Grasso et al 1983;Incoronato & Nardi 1989). Significant rotation of Pleistocene rocks (Scheepers & Langereis 1994) indicates that bend formation is ongoing.…”

Carbonate slope re‐sedimentation in a tectonically‐active setting (Western Sicily Cretaceous Escarpment, Italy)

“…Other studies concentrated on the Cretaceous magmatic intrusions exposed in the south‐western sector of the peninsula (western part of the Mt Sparagio ridge; see Fig. C; Bellia et al ., ; Catalano et al ., ; Speziale, ).…”

Understanding Paleomagnetic Rotations in Sicily: Thrust Versus Strike‐Slip Tectonics

“…The reevaluation of six sites sampled by Channell et al (, ) west of Palermo (Figure b and Table S1) gives for the Panormide Unit an average rotation of 126° ± 15°. Three Panormide sites from other sectors of the Sicily belt gave smaller 87°–95° rotations and were not considered: site P09 (Custonaci, average of four subsites) was sampled by Schult () in upper Cretaceous volcanics NE of Trapani (Figure b), but the work of Catalano et al () later showed that Jurassic‐Cretaceous volcanics of western Sicily yield mostly unreliable paleomagnetic results; sites P07–P08 (Aculeia, Madonie) were sampled by Channell et al () in the Madonie Mts. of central Sicily, which likely underwent a different rotational history.…”

“…They recognized for the first time that the internal units had undergone greater CW rotations than the external units and related the rotation to the dextral shear exerted by the Calabro-Peloritan block (Figure 1a) on the Sicilian Maghrebides. Catalano et al (1984) sampled 16 sites in the Jurassic-Cretaceous volcanics from NW Sicily. They mostly found unreliable data, although they first documented a >90°rotation of the Panormide unit and first proposed that the rotational differences between different localities could reflect differential nappe rotations.…”

“…Tectonics work of Catalano et al (1984) later showed that Jurassic-Cretaceous volcanics of western Sicily yield mostly unreliable paleomagnetic results; sites P07-P08 (Aculeia, Madonie) were sampled by Channell et al (1990) in the Madonie Mts. of central Sicily, which likely underwent a different rotational history.…”