Garnet-spinel-pyroxenite xenoliths from hyblean plateau (South-eastern Sicily, Italy)

Atzori, Piero; Mazzoleni, Paolo; Punturo, Rosalda; Scribano, Vittorio

doi:10.1007/bf01164494

Cited by 15 publications

(12 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, if the gravity anomaly was related to foreland dynamics, it should run subparallel to the orogenic front like in the Pelagian foreland (Moretti & Royden, ). By contrast, voluminous crustal mafic intrusions previously evoked for the Hyblean region (Atzori et al, ; Schmincke et al, ; Yellin‐Dror et al, ) and evidenced nearby in the Sicily Channel (Civile et al, ; Lodolo et al, ) should also be associated to positive gravity anomalies as observed in the SW Iberia margin (Neres et al, ) or in the Adriatic region (Mancinelli et al, ).…”

Section: Discussionmentioning

confidence: 90%

Deep Origin of the Dome‐Shaped Hyblean Plateau, Southeastern Sicily: A New Tectono‐Magmatic Model

et al. 2019

View full text Add to dashboard Cite

Southeastern Sicily is characterized by a prominent topography known as the Hyblean Plateau.It is commonly considered as a flexural bulge formed by the northwest plunging of the Hyblean-Malta platform beneath the Sicilian Fold and Thrust Belt. However its noncylindrical shape and multiphase uplift history correlated to the Late Miocene and Plio-Pleistocene volcanism outline a possible magmatic control on the Hyblean Plateau topographic expression. We argue, using 2-D flexural models, that the flexural bending alone is unlikely to explain the high anomalous elevation of the Hyblean Plateau. Moreover, topographic analysis show that the Hyblean Plateau has a dome shape composed of radially tilted preserved surfaces defining individual blocks. The block edges seem to be related to deep-seated inherited faults. Using an analogue modeling approach, we show that magmatic intrusions beneath the thick Meso-Cenozoic sedimentary cover can reproduce the first-order morphology of the Hyblean Plateau when a structural inheritance is imposed. Accordingly, we propose a tectono-magmatic model that favors mafic sill intrusions as the major uplift source for the topographic anomaly. However, to explain the strong positive Bouguer anomaly, a deeper high-density intracrustal body is needed. Moho uprising related to Mesozoic rifting or mafic lower crust underplating/intraplating since the Late Cretaceous can be evoked. The small wavelength of the topography and the deep intracrustal mass anomaly makes the lithospheric elastic stresses sufficiently high to maintain a nonisostatic state over the geological time scales.Plain Language Summary A prominent dome-shaped topography known as the Hyblean Plateau overcomes southeastern Sicily. It is commonly considered as originated from foreland flexural bulging of the Hyblean-Malta platform in response to the southeastward migrating Sicilian orogenic wedge. However, its nonlinear shape and its multiphase uplift history correlate to the Late Miocene and Plio-Pleistocene volcanic activity and hence suggest a possible magmatic control on the formation of the Hyblean Plateau. We show that flexural bending alone is unlikely to explain the subcircular topography of the Hyblean Plateau using 2-D flexural models. Moreover, subsurface analysis coupled to an analogue modeling approach shows that the subcircular pattern is subdivided into radially tilted blocks whose edges seem to be related to inherited fault zones. The tectono-magmatic model proposed here minimizes the flexural component to the Hyblean rise and prefers mafic sill intrusions in the upper crust as the major uplift source. However, gravity anomalies suggest a deeper high-density intracrustal body beneath the Hyblean Plateau which can be related to the Meso-Cenozoic history. The lack of isostatic equilibrium in this region can be related to the small length scale of the topography and the inferred intracrustal high-density body which makes the lithosphere rigid enough to support these anomalies.

show abstract

Section: Discussionmentioning

confidence: 90%

Deep Origin of the Dome‐Shaped Hyblean Plateau, Southeastern Sicily: A New Tectono‐Magmatic Model

et al. 2019

View full text Add to dashboard Cite

show abstract

“…1) and the deeper water alkali basaltic Valle Guffari seamount (VGS)-the focus of our study-are characterized by well-exposed subsurface structures and associated tephra rings. These volcanic edifices are wellknown for a wide spectrum of ultramafic and gabbroic xenoliths (Scribano 1987a, b;Tonarini et al 1996;Atzori et al 1999;Punturo et al 2000;Scribano et al (2006), Sapienza et al 2009). …”

Section: Geological Settingmentioning

confidence: 98%

“…Ultramafic xenoliths (ca. 20-25 vol.%) in the diatreme fill are well studied (Scribano 1987a, b;Tonarini et al 1996;Atzori et al 1999;Punturo et al 2000;Sapienza et al 2009). …”

Section: Bedrock Xenolithsmentioning

confidence: 99%

Iblean diatremes 3: volcanic processes on a Miocene carbonate platform (Iblean Mountains, SE-Sicily): a comparison of deep vs. shallow marine eruptive processes

Suiting

Schmincke

2011

Bull Volcanol

View full text Add to dashboard Cite

Evolution and magma fragmentation processes of two contrasting, well-exposed diatreme complexes interbedded with Late Miocene calcareous marine sediments in distinct sedimentary environments of a carbonate platform (Iblean Plateau, Sicily) are compared with each other. The nephelinitic Cozzo Molino diatreme (CMD) to the east developed in shallow water (0-80 m water depth); the alkali basaltic Valle Guffari seamount (VGS) to the west grew on a deeper water carbonate ramp (150-200 m water depth). We focus on the dominant boundary conditions inferred to have governed depth of magma fragmentation and subaqueous emplacement mechanisms: water depth, physical nature of host rocks, magma composition, and inferred differences in initial volatile concentrations. There are gross similarities in the composition of the two moderately evolved magmas. The low-viscosity magmas in both diatremes were laden with xenoliths originating from mantle to lower crustal sites. Although similar, the eastern shallow water CMD was likely more volatile-rich, with magma fragmented prior to reaching the surface and the surrounding tephra cone was partly emergent. The eruptions of the entirely submarine VGS diatreme complex in the deeper water environment were dominated by interaction of soft sediment and alkali basaltic magma or a pre-fragmented volatile-particle mixture. Eruption columns were, thus, strongly damped and the submarine complex never pierced the water surface.

show abstract

“…Scribano [37], following an established criterion [38], divided the Hyblean pyroxenites in two major groups on the basis of the composition of their clinopyroxene constituents, the Al-diopside and Cr-diopside groups. Hyblean pyroxenite xenoliths were studied by [33,37,[39][40][41][42][43][44][45]. All these studies agree that the Hyblean pyroxenites are igneous cumulates formed at mantle depths.…”

Section: Hyblean Diatremes and Their Xenolithsmentioning

confidence: 97%

Convective Instability in Intraplate Oceanic Mantle Caused by Amphibolite-Derived Garnet-Pyroxenites—A Xenolith Perspective (Hyblean Plateau, Sicily)

Scribano

Carbone

2020

Geosciences

View full text Add to dashboard Cite

Geochemical characteristics of middle ocean ridge basalts (MORBs) testify partial melting of spinel-peridotite mixed with a few amounts of garnet-pyroxenite. The latter can be considered either autochthonous products of the crystallization of partial melts in the sub-oceanic mantle or allocthonous recycled crustal materials originated in subduction contexts. Here we suggest the “autocthnous recycled” origin for garnet-pyroxenites. Such a hypothesis derives from the study of garnet-bearing pyroxenite xenoliths from the Hyblean Plateau (Sicily). These consist of Al-diopside, pyralspite-series garnet, Al-spinel and Al-rich orthopyroxene. Trace element distribution resembles an enriched MORB but lower chromium. Major-element abundances closely fit in a tschermakitic-horneblende composition. Assuming that a high-Al amphibolite was formed by hydrothermal metasomatism of a troctolitic gabbro in a slow-spreading ridge segment, a transient temperature increasing induced dehydroxilization reaction in amphiboles, giving Al-spinel-pyroxenite and vapor as products. Garnet partially replaced spinel during an isobaric cooling stage. Density measurements at room conditions on representative samples gave values in the range 3290–3380 kg m−3. In general, a density contrast ≥300 kg m−3 can give rise to convective instability, provided a sufficient large size of the heavy masses and adequate rheological conditions of the system. Garnet-pyroxenite lumps can therefore sink in the underlying mantle, imparting the “garnet geochemical signature” to newly forming basaltic magma.

show abstract

Garnet-spinel-pyroxenite xenoliths from hyblean plateau (South-eastern Sicily, Italy)

Cited by 15 publications

References 24 publications

Deep Origin of the Dome‐Shaped Hyblean Plateau, Southeastern Sicily: A New Tectono‐Magmatic Model

Deep Origin of the Dome‐Shaped Hyblean Plateau, Southeastern Sicily: A New Tectono‐Magmatic Model

Iblean diatremes 3: volcanic processes on a Miocene carbonate platform (Iblean Mountains, SE-Sicily): a comparison of deep vs. shallow marine eruptive processes

Convective Instability in Intraplate Oceanic Mantle Caused by Amphibolite-Derived Garnet-Pyroxenites—A Xenolith Perspective (Hyblean Plateau, Sicily)

Contact Info

Product

Resources

About