Wyniki wyszukiwania - BazTech

1

Tectonic evolution of the Sicilian Thrust System (central Mediterranean)

Napoli G., Nigro F., Renda P., Ślqczka A., Favara R.

Geological Quarterly

|

2012

|

Vol. 56, No. 4

579--600

EN

The Sicilian Thrust System (STS) is a south-verging (Africa-verging) fold-and-thrust belt including a Mesozoic-Paleogene sedimentary sequence. This thrust stack owes its origin to the deformation of pre-orogenic strata deposited in different palaeogeographic domains belonging to passive margins of the African plate. The STS was deformed during the Neogene, following the closure of the Tethys Ocean and the continental collision between the Sardo-Corso Block and the north Africa margins. The thrust pile was detached from the underlying basement during the Miocene-Pleistocene. The regional-scale structural setting recognized allows us to reconstruct the tectonic evolution of the STS as follows: I - piggy-back thrusting from the Late Oligocene to the Langhian, inducing the building of the Inner Sicilian Chain (ISC); II - piggy-back thrusting from the Langhian to the Tortonian, inducing the formation of the Middle Sicilian Chain (MSC); III - generalized extensional deformation in the chain-foredeep-foreland system from the Tortonian to the Early Pliocene; IV-a new onset of piggy-back thrusting after the Early Pliocene allowed the building of the Outer Sicilian Chain and out-of-sequence thrusting in the previously developed ISC and MSC.

2

Probable root structures and associated trace fossils from the Lower Pleistocene calcarenites of Favignana Island, southern Italy : dilemmas of interpretation

Uchman A., Ślączka A., Renda P.

Geological Quarterly

|

2012

|

Vol. 56, No. 4

745–-756

EN

Two types of large, branched structures from the Lower Pleistocene (Calabrian) high-energy calcarenites of Favignana Island are described: Faviradixus robustus gen. et sp. nov. and Egadiradixus rectibrachiatus gen. et sp. nov. They may be interpreted as root structures of large plants, trees and trees or shrubs, respectively. The former taxon co-occurs with the marine animal trace fossils Ophiomorpha nodosa, Ophiomorpha isp., Thalassinoides isp. and Beaconites isp. The interpretation as root structures although tentative is probable and can be related to short emergence episodes for the formation of E. rectibrachiatus or to longer emergence, responsible for the discontinuity at the base of the overlying Tyrrhenian deposits, for F. robustus. Calcified root mats of smaller plants associated with the Tyrrhenian or younger emergence surfaces are common.

3

Extensional tectonics during Maghrebides Chain building since late Miocene : examples from Northern Sicily

Giunta G., Nigro F., Renda P.

Annales Societatis Geologorum Poloniae

|

2000

|

Vol. 70, No. 1

81-98

EN

The Northern Sicilian-Maghrebian Chain courses W-E from the Trapani Mts to the Peloritani Mts and is composed by a set of tectonic units deriving from the Miocene-Pleistocene deformation of the Northern African Continental Margin. Inside it three main geotectonic elements ("external", Sicilide and "Austroalpine") are present and outcrop juxtaposed with a W-E trend. The external element composes the more western Trapani, Palermo and Western Madonie Mts, the Sicilide composes the Eastern Madonie and Nebrodi Mts, while the "Austroalpine" composes the more eastern Peloritani Mts. The orogen shows a culmination in the Trapani Mts and a depression in the Peloritani Mts. The main plicative stages are relatable to late Oligocene-early Miocene from the more internal sectors, while the deformation of the more external sectors starts from early-middle Miocene. The Sicilian chain body is re-involved in tectonism since late Tortonian, which persists until the recent time. During this interval, the deformation of the Sicilian Chain continued by activation of fault systems with different displacements. In the present paper, an important extensional tectonic stage is recognised, starting from the Tortonian; it is supported by structural data and shows through several geological sections across the northern sectors of the Sicilian orogen. This deformation is of exceeded wedge critical taper values, controls the early stages of the Tyrrhenian Basin opening, and is represented by low-angle fault system, producing tectonic omissions in the stratigraphic sequence. The detachment fault system is subsequently displaced by a complicated grid of Plio-Pleistocene net- and strike-slip fault system that controls the genesis of tectonic depressions in the northern off-shore areas of the Sicilian Chain. This neotectonic system may be reconnect to a W-E trending simple shear system, which controls the more recent Tyrrhenian Basin development.

4

The North-Central Sicily Belt : structural setting and geological evolution

Nigro F., Renda P.

Annales Societatis Geologorum Poloniae

|

1999

|

Vol. 69, No. 1-2

49-61

EN

North-Central Sicily represents an Apenninic-Maghrebian Chain sector, deriving from the Miocene- Pliocene deformation of different palaeogeographic domains-derived successions (carbonate platforms and pelagic basins), piled-up in ramp-flat and duplex style, and belonging during the Mesozoic-Tertiary to the Northern African Continental Margin. These domains are represented by outcropping basinal sedimentary successions (Imerese-Sicanian Basin), geometrically interposed between carbonate platform rock bodies: the Panormide (innermost) and the Hyblean-Pelagian Domains (more external). In this paper, using stratigraphic and structural data, we propose a new palaeogeographic model, in which the main differences from previous interpretations consist in the position of the Imerese Basin, here identified as the juncture between the Panormide Domain and the Sicanian Basin Auct., and the position of the Trapanese pelagic carbonate platform, considered as the juncture between the Hyblean-Pelagian Domain and the Sicanian Basin Auct. Tectono-sedimentary steps characterising the evolution of the Sicilian Miocene-Pliocene Foredeep illustrate the deformational history of the area. Two geological cross-sections depict the structural architecture of the tectonic edifice, characterised by different thrust sheets piled-up during the Miocene-Pleistocene time. The more external tectonic units are formed by elements deriving from the Plio-Pleistocene deformation of the northern margin of the Hyblean-Pelagian Domain. The "intermediate" tectonic units derive from the Miocene-Pliocene deformation of the Imerese- Sicanian Domain and the inner tectonic units are constituted by Panormide and Sicilide Domains-derived successions, deformed during the Miocene. A mostly neotectonics-related transcurrent faults reoriented the previous thrust sheets through NW-SE and W-E trending faults, producing large-scale positive flower structures which involved the geometrically deepest Hyblean-Pelagian substrate.

5

Plio-Pleistocene wrench tectonics in the Western Sicily Chain

Nigro F., Renda P.

Annales Societatis Geologorum Poloniae

|

1999

|

Vol. 69, No. 3-4

99-112

EN

Western Sicily represents a fragment of the Apenninic-Maghrebian Chain, largely built during the Miocene and formed by a set of tectonic units with southern vergence of folds and ramp-flat style of thrust surfaces. The thrust tectonics-related structures are displaced by a high-angle fault system, which bounds the main Mesozoic "carbonatic massifs" and generally interpreted as a neotectonic dip-slip extensional tectonics-related faults. The present paper, with the support of mesostructural analysis, presents an important Plio-Pleistocene strike-slip tectonics, represented by high-angle net- and strike-slip fault system. Different scale flower structures and associated fold systems, which cut the Miocene tectonic units, characterise the areas along the main transcurrent fault zones. Strike-slip neotectonics is mostly represented by right-lateral NW-SE/W-E and left-lateral N-S/NE-SW transcurrent faults, which may represent a W-E trending deep-seated Riedel system connected to the Tyrrhenian spreading. The NW-SE first order synthetic structures appear to control the opening of several rhomboidal tectonic depressions located in north-western Sicily and its offshore, and are counteracted by W-E trending transpressional structures located in the central Sicily mainland. An attempt at semi-quantitative restoration shows the neotectonic evolution of north-western Sicily during the Pliocene and Pleistocene, characterised by the progressive activation towards the east of en-échelon strike-slip fault strand, in an overall horsetail splay geometry, which produced releasing bends in off-shore and restraining bends in the mainland.

6

Depositional processes in a Late Miocene posttectonic basin: Terravecchia Formation, Scillato Basin, Sicily

Abbate B., Incandela A., Renda P., Ślączka A.

Annales Societatis Geologorum Poloniae

|

1999

|

Vol. 69, No. 1-2

27-48

EN

Terravecchia Formation in the Scillato Basin is a good example of development of a post-tectonic basin. Practically continuous exposures across that basin give the rare possibility to observe the lateral distribution of lithofacies and gradual changes of sedimentary succession from an alluvial fan, fluvial plan to lacustrine and, eventually, to marine setting. The alluvial fan deposits are generally represented by polymictic, disorganised or crudely organised conglomerates representing mainly flow and debris flow deposits. The fluvial plain association is characterized generally by cross-bedded sandstones with streaks of conglomerates laid down within a channel bar system. Flood-plain deposits are subordinate. Sedimentary structures suggest deposition in a braided river. The fluvial plain association pass laterally to lacustrine/fluvial plain deposits represented by grey to pinkish mudstones with channelised sandstones. As an effect of subsidence the Scillato Basin was invaded by marine/brackish environment, and marly mudstones and siltstones with subordinate sandstones were deposited. That variability of sedimentary facies can be explained by vertical tectonic movements.

PL

Późnomioceńska formacja Terravecchia zachowana w basenie Scillato, stanowi dobry przykład rozwoju basenu posttektonicznego. Ciąg bardzo dobrych odsłonięć w poprzek basenu pozwolił na szczegółowe obserwacje rozkładu litofacji, struktur sedymentacyjnych oraz asocjacji facjalnych i ich wzajemnych związków. Wyróżnionych zostało kilka środowisk sedymentacyjnych, od stożka aluwialnego, przez rzekę roztokową po środowisko jeziorne i morskie. Osady stożka aluwialnego reprezentowane są przez czerwone i żółte, polimiktyczne zepieńce, o strukturach zarówno bezładnych jak i uporządkowanych, powstałe w wyniku działania prądów i spływów rumoszowych. Osady rzeki roztokowej to głównie przekątnie warstwowane piaskowce związane z różnego rodzaju łachami piaszczystymi. Mułowcowe osady równi zalewowych zachowały się tylko sporadycznie. Osady rzeczne przechodzą lateralnie w mułowcowe osady jeziorne z licznymi osadami kanałowymi w ich dolnej części. Pod koniec rozwoju basenu, w rezultacie subsydencji tektonicznej, nastąpiła ingresja morska i powyżej osadów rzeczno-jeziornych rozpoczęła się sedymentacja osadów brakiczno-morskich z poziomami fauny.