scholarly journals Neogene-Quaternary magmatic activity and its geodynamic implications in the Central Mediterranean region

1997 ◽  
Vol 40 (3) ◽  
Author(s):  
G. Serri
Keyword(s):  
Middle Miocene ◽  
Structural Evolution ◽  
Space Distribution ◽  
Central Mediterranean ◽  
Arc Volcanism ◽  
Time Space ◽  
Lithospheric Extension ◽  
Geodynamic Models ◽  
Back Arc ◽  
Roman Province

The petrogenesis and time/space distribution of the magmatism associated with the formation of the Northern and Southern Tyrrhenian basins, together with the directions and ages of lithospheric extension and/or spreading north and south of the 410N discontinuity, show that the two arc/back-arc systems have undergone a different structural evolution at least since the middle Miocene (Langhian). The geochemical components involved in the genesis of the heterogeneities of the mantle sources of this magmatism require two separate, compositionally different slabs: 1) an old oceanic (Ionian) lithosphere still seismically active below the Calabrian arc and the Southern Tyrrhenian region; 2) an almost seismically inactive continental (Adriatic) lithosphere which carried large amounts of upper crustal materials within the upper mantle under the NW Roman Province/Tuscan/Northern Tyrrhenian region. The proposed geodynamic models require: 1) for the Northern Tyrrhenian/Northern Apenninic arc/back-arc system, the delamination and foundering of the Adriatic continental lithosphere as a consequence of the continental collision between the Corsica block and the Adriatic continental margin. This delamination process, which is still ongoing, probably started in the early-middle Miocene, but earlier than 15-14 Ma, as indicated by the age and petrogenesis of the first documented magmatic episode (the Sisco lamproite) of the Northern Apennine orogenesis; 2) for the Southern Tyrrhenian/Southern Apenninic-Calabrian arc/back-arc system, the roll-back subduction and back-arc extension driven by gravitational sinking of the Ionian oceanic subducted lithosphere. This process started after the end of the arc volcanism of Sardinia (about 13 Ma) but earlier than the first recorded episode of major rifting (about 9 Ma) in the Southern Tyrrhenian back-arc basin.

scholarly journals Basic Role of Extrusion Processes in the Late Cenozoic Evolution of the Western and Central Mediterranean Belts

Geosciences ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 499
Author(s):  
Marcello Viti ◽  
Enzo Mantovani ◽  
Daniele Babbucci ◽  
Caterina Tamburelli ◽  
Marcello Caggiati ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Mediterranean Area ◽  
Space Distribution ◽  
Tectonic Activity ◽  
Central Mediterranean ◽  
Tectonic Processes ◽  
Time Space ◽  
Back Arc ◽  
Orogenic Belts

Tectonic activity in the Mediterranean area (involving migrations of old orogenic belts, formation of basins and building of orogenic systems) has been determined by the convergence of the confining plates (Nubia, Arabia and Eurasia). Such convergence has been mainly accommodated by the consumption of oceanic and thinned continental domains, triggered by the lateral escapes of orogenic wedges. Here, we argue that the implications of the above basic concepts can allow plausible explanations for the very complex time-space distribution of tectonic processes in the study area, with particular regard to the development of Trench-Arc-Back Arc systems. In the late Oligocene and lower–middle Miocene, the consumption of the eastern Alpine Tethys oceanic domain was caused by the eastward to SE ward migration/bending of the Alpine–Iberian belt, driven by the Nubia–Eurasia convergence. The crustal stretching that developed in the wake of that migrating Arc led to formation of the Balearic basin, whereas accretionary activity along the trench zone formed the Apennine belt. Since the collision of the Anatolian–Aegean–Pelagonian system (extruding westward in response to the indentation of the Arabian promontory) with the Nubia-Adriatic continental domain, around the late Miocene–early Pliocene, the tectonic setting in the central Mediterranean area underwent a major reorganization, aimed at activating a less rested shortening pattern, which led to the consumption of the remnant oceanic and thinned continental domains in the central Mediterranean area.

Refining the Paleoproterozoic tectonothermal history of the Penokean Orogen: New U-Pb age constraints from the Pembine-Wausau terrane, Wisconsin, USA

2021 ◽  
Author(s):  
Jian-Wei Zi ◽  
Stephen Sheppard ◽  
Janet R. Muhling ◽  
Birger Rasmussen
Keyword(s):  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Time Frame ◽  
Metamorphic Event ◽  
Published Data ◽  
Banded Iron Formations ◽  
Time Space ◽  
Lithospheric Extension ◽  
History Of ◽  
Back Arc

An enduring problem in the assembly of Laurentia is uncertainty about the nature and timing of magmatism, deformation, and metamorphism in the Paleoproterozoic Wisconsin magmatic terranes, which have been variously interpreted as an intra-oceanic arc, foredeep or continental back-arc. Resolving these competing models is difficult due in part to a lack of a robust time-frame for magmatism in the terranes. The northeast part of the terranes in northern Wisconsin (USA) comprise mafic and felsic volcanic rocks and syn-volcanic granites thought to have been emplaced and metamorphosed during the 1890−1830 Ma Penokean orogeny. New in situ U-Pb geochronology of igneous zircon from the volcanic rocks (Beecher Formation), and from two tonalitic plutons (the Dunbar Gneiss and Newingham Tonalite) intruding the volcanic rocks, yielded crystallization ages ranging from 1847 ± 10 Ma to 1842 ± 7 Ma (95% confidence). Thus, these rocks record a magmatic episode that is synchronous with bimodal volcanism in the Wausau domain and Marshfield terrane farther south. Our results, integrated with published data into a time-space diagram, highlight two bimodal magmatic cycles, the first at 1890−1860 Ma and the second at 1845−1830 Ma, developed on extended crust of the Superior Craton. The magmatic episodes are broadly synchronous with volcanogenic massive sulfide mineralization and deposition of Lake Superior banded iron formations. Our data and interpretation are consistent with the Penokean orogeny marking west Pacific-style accretionary orogenesis involving lithospheric extension of the continental margin, punctuated by transient crustal shortening that was accommodated by folding and thrusting of the arc-back-arc system. The model explains the shared magmatic history of the Pembine-Wausau and Marshfield terranes. Our study also reveals an overprinting metamorphic event recorded by reset zircon and new monazite growth dated at 1775 ± 10 Ma suggesting that the main metamorphic event in the terranes is related to the Yavapai-interval accretion rather than the Penokean orogeny.

Grossplots: a Method for Estimating the Temperature State of the Earth and of Australia, Cretaceous to Middle Miocene

1997 ◽  
Vol 45 (3) ◽  
pp. 359 ◽  
Author(s):  
L. A. Frakes
Keyword(s):  
Middle Miocene ◽  
Global Climate ◽  
Interval Data ◽  
Late Eocene ◽  
Space Distribution ◽  
Mean Annual Temperature ◽  
The North ◽  
Early Oligocene ◽  
Time Space ◽  
Temperature State

Grossplots are compilations of globally distributed palaeotemperature data onto latitude versus age plots, which are then contoured. The results specifically show the distribution of temperature over the globe and its variations over the Cretaceous to Middle Miocene interval. Data for continents and oceans are plotted separately in this investigation, and each such grossplot is in accord with the known climate changes of this time. The general scarcity of quantitative palaeotemperature information for Australia can be rectified by deriving, from the global continental grossplot, the relationship between mean annual temperature and latitude. When these are applied to the latitude band progressively occupied by Australia, the following observations can be made: (1) during the Early Cretaceous, the south-east of the continent was subjected to freezing wintertime temperatures; (2) peak warming of northern Australia was attained in the Turonian–Santonian, but this was followed by cooling later in the Cretaceous; (3) Early Tertiary warming until the Late Eocene particularly affected the northern half of the continent, but this region then underwent the most severe cooling in the Early Oligocene; (4) subsequently, the whole of the continent cooled uniformly from conditions only slightly warmer than at present. Despite Australia’s equatorward march, the Late Cretaceous to Palaeocene climates of the continent have been influenced more effectively by changes in the global climate state. However, global cooling since the Eocene has been less effective than drift in controlling the warming climate of Australia. The time–space distribution of precipitation over Australia is estimated from the global relationship between terrestrial temperature and rainfall. The Eocene experienced the heaviest rainfall (> 1560 mm year-1, in the north only), and the Eocene to Middle Miocene experienced moderately high rates (> 500 mm year-1 in the northern three-quarters of the continent). Tertiary brown coals in southern regions were formed in proximity to areas of high rainfall. Continentwide low rates (< 500 mm year-1; semi-arid) are suggested for the Cretaceous, except for wet conditions in the north during the Albian–Santonian and the Late Maastrichtian. Estimates of precipitation are subject to factors such as continentality and location of moisture sources, which cannot be evaluated at present.

Analogue modeling and tectono-stratigraphic evolution of the eastern Sicilian fold-and-thrust belt

2020 ◽  
Author(s):  
Maxime Henriquet ◽  
Stéphane Dominguez ◽  
Giovanni Barreca ◽  
Jacques Malavieille ◽  
Carmelo Monaco
Keyword(s):  
Large Scale ◽  
Middle Miocene ◽  
General Structure ◽  
Foreland Basin ◽  
Accretionary Wedge ◽  
Thrust Belt ◽  
Central Mediterranean ◽  
Fold And Thrust Belt ◽  
Structural Architecture ◽  
Back Arc

&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; In Central Mediterranean, the Sicilian Fold and Thrust Belt (SFTB) and Calabrian Arc, as well as the whole Apennine-Maghrebian belt, result from the subduction and collision with drifted micro-continental terranes. These terranes detached from the European margin and migrated southeastward in response to Neogene slab roll-back and associated back-arc extension. From N to S, the SFBT is divided in 4 main tectono-stratigraphic domains: (1) the Calabro-Peloritani terrane, drifted from the European margin and detached from the Corso-Sarde block since the back-arc opening of the Tyrrhenian basin, (2) the Neotethyan pelagic cover, constituting the remnants of the Alpine Tethys oceanic accretionary wedge, (3) the folded and thrusted platform (Panormide) and basinal (Imerese-Sicanian) series of the down-going African margin, and (4) the undeformed african margin foreland (Hyblean).&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; The scarce good quality outcrops of key tectono-stratigraphic units and crustal scale seismic lines makes the structural architecture of the SFTB very controversial, as testified by the wide variety of tectonic interpretations (Bianchi et al., 1987; Roure et al., 1990; Bello et al., 2000; Catalano et al., 2013). Major outstanding issues particularly concern: (1) the occurence of Alpine Tethys units far from the region where the remnants of the Tethyan accretionary wedge outcrop (Nebrodi range); in a forearc position above the Peloritani block north of the SFTB and in an active foreland context along the southern front of SFTB; (2) the diverging suggested tectonic styles, from stacked large-scale tectonic nappes to foreland imbricated thrust systems rooted into a main basal d&amp;#233;collement; and (3), the deposition environnement of substantial units such as the widespread Numidian Flyschs, from syntectonic foreland basin to wedge-top sedimentation.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; We used 2D analogue models to investigate the mechanical processes involved in the formation of the SFTB starting from the Oligocene Tethys subduction to the Middle Miocene - Late Pliocene continental collision with the African paleo-margin. Based on a detailed tectono-stratigraphic synthesis, complemented by field observations, we reproduce the first-order mechanical stratigraphy of the sedimentary and basement units involved in the SFTB as well as the structural inheritance of the African margin. Our models also include: syntectonic erosion and sedimentation, syn-orogenic flexure and adjustable material output via a &amp;#8220;subduction channel&amp;#8220;.&amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; The analog models succeed in reproducing the general structure of the SFTB and main tectono-stratigraphic correlations. For instance, the Panormide platform is underthrusted beneath the Alpine Tethys accretionary wedge, then stacked above the Imerese basinal units and belatedly exhumed in response to basement anticlinal stack. Our results also suggest that the Alpine Tethys units couldn&amp;#8217;t overthrust the whole African foreland in the Middle Miocene, nor be back-thrusted over the forearc basin during the Burdigalian. We rather favor a gravity-induced sedimentation process inducing reworking of the tethysian sediments at specific building stages of the accretionary wedge. The structural architecture of the modeled orogenic wedge is also consistent with a SFTB growing by frontal accretion and basal underplating of mechanically resistant stratigraphic units rather than by large-scale nappe overthrusting.&amp;#160;&amp;#160;&lt;/p&gt;

Age, chemistry, and tectonic setting of Miramichi terrane (Early Paleozoic) volcanic rocks, eastern and east-central Maine, USA

2021 ◽  
Vol 57 ◽  
pp. 239-273
Author(s):  
Allan Ludman ◽  
Christopher McFarlane ◽  
Amber T.H. Whittaker
Keyword(s):  
New Brunswick ◽  
Subduction Zone ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Calc Alkaline ◽  
East Central ◽  
Arc Volcanism ◽  
Middle Ordovician ◽  
Volcanic Suite ◽  
Back Arc

Volcanic rocks in the Miramichi inlier in Maine occur in two areas separated by the Bottle Lake plutonic complex: the Danforth segment (Stetson Mountain Formation) north of the complex and Greenfield segment to the south (Olamon Stream Formation). Both suites are dominantly pyroclastic, with abundant andesite, dacite, and rhyolite tuffs and subordinate lavas, breccias, and agglomerates. Rare basaltic tuffs and a small area of basaltic tuffs, agglomerates, and lavas are restricted to the Greenfield segment. U–Pb zircon geochronology dates Greenfield segment volcanism at ca. 469 Ma, the Floian–Dapingian boundary between the Lower and Middle Ordovician. Chemical analyses reveal a calc-alkaline suite erupted in a continental volcanic arc, either the Meductic or earliest Balmoral phase of Popelogan arc activity. The Maine Miramichi volcanic rocks are most likely correlative with the Meductic Group volcanic suite in west-central New Brunswick. Orogen-parallel lithologic and chemical variations from New Brunswick to east-central Maine may result from eruptions at different volcanic centers. The bimodal Poplar Mountain volcanic suite at the Maine–New Brunswick border is 10–20 myr younger than the Miramichi volcanic rocks and more likely an early phase of back-arc basin rifting than a late-stage Meductic phase event. Coeval calc-alkaline arc volcanism in the Miramichi, Weeksboro–Lunksoos Lake, and Munsungun Cambrian–Ordovician inliers in Maine is not consistent with tectonic models involving northwestward migration of arc volcanism. This >150 km span cannot be explained by a single east-facing subduction zone, suggesting more than one subduction zone/arc complex in the region.

scholarly journals Regional Seismic Attribute Analysis and Tectono-Stratigraphy of Offshore South-Western Taranaki Basin, New Zealand

2021 ◽  
Author(s):  
◽  
Jan Robert Baur
Keyword(s):  
New Zealand ◽  
Deep Water ◽  
Middle Miocene ◽  
Plate Boundary ◽  
Water Area ◽  
Passive Margin ◽  
Extensional Faulting ◽  
Deep Water Area ◽  
Back Arc ◽  
Shelf Margin

<p>This study investigates the nature, origin, and distribution of Cretaceous to Recent sediment fill in the offshore Taranaki Basin, western New Zealand. Seismic attributes and horizon interpretations on 30,000 km of 2D seismic reflection profiles and three 3D seismic surveys (3,000 km²) are used to image depositional systems and reconstruct paleogeography in detail and regionally, across a total area of ~100,000 km² from the basin's present-day inner shelf to deep water. These data are used to infer the influence of crustal tectonics and mantle dynamics on the development of depocentres and depositional pathways. During the Cretaceous to Eocene period the basin evolved from two separate rifts into a single broad passive margin. Extensional faulting ceased before 85 Ma in the present-day deep-water area of the southern New Caledonia Trough, but stretching of the lithosphere was higher (β=1.5-2) than in the proximal basin (β<1.5), where faulting continued into the Paleocene (~60 Ma). The resulting differential thermal subsidence caused northward tilting of the basin and influenced the distribution of sedimentary facies in the proximal basin. Attribute maps delineate the distribution of the basin's main petroleum source and reservoir facies, from a ~20,000 km²-wide, Late Cretaceous coastal plain across the present-day deep-water area, to transgressive shoreline belts and coastal plains in the proximal basin. Rapid subsidence began in the Oligocene and the development of a foredeep wedge through flexural loading of the eastern boundary of Taranaki Basin is tracked through the Middle Miocene. Total shortening within the basin was minor (5-8%) and slip was mostly accommodated on the basin-bounding Taranaki Fault Zone, which detached the basin from much greater Miocene plate boundary deformation further east. The imaging of turbidite facies and channels associated with the rapidly outbuilding shelf margin wedge illustrates the development of large axial drainage systems that transported sediment over hundreds of kilometres from the shelf to the deep-water basin since the Middle Miocene. Since the latest Miocene, south-eastern Taranaki Basin evolved from a compressional foreland to an extensional (proto-back-arc) basin. This structural evolution is characterised by: 1) cessation of intra-basinal thrusting by 7-5 Ma, 2) up to 700 m of rapid (>1000 m/my) tectonic subsidence in 100-200 km-wide, sub-circular depocentres between 6-4 Ma (without significant upper-crustal faulting), and 3) extensional faulting since 3.5-3 Ma. The rapid subsidence in the east caused the drastic modification of shelf margin geometry and sediment dispersal directions. Time and space scales of this subsidence point to lithospheric or asthenospheric mantle modification, which may be a characteristic process during back-arc basin development. Unusual downward vertical crustal movements of >1 km, as inferred from seismic facies, paleobathymetry and tectonic subsidence analysis, have created the present-day Deepwater Taranaki Basin physiography, but are not adequately explained by simple rift models. It is proposed that the distal basin, and perhaps even the more proximal Taranaki Paleogene passive margin, were substantially modified by mantle processes related to the initiation of subduction on the fledgling Australia-Pacific plate boundary north of New Zealand in the Eocene.</p>

About this title - Volcanism in Antarctica: 200 Million Years of Subduction, Rifting and Continental Break-up

10.1144/m55 ◽  
2021 ◽  
Vol 55 (1) ◽  
pp. NP-NP
Keyword(s):  
Lava Lake ◽  
Rift System ◽  
West Antarctic ◽  
Continental Arc ◽  
Lithospheric Extension ◽  
Break Up ◽  
Felsic Volcanic ◽  
Mafic Volcanism ◽  
Back Arc ◽  
West Antarctic Rift System

This memoir is the first to review all of Antarctica's volcanism between 200 million years ago and the Present. The region is still volcanically active. The volume is an amalgamation of in-depth syntheses, which are presented within distinctly different tectonic settings. Each is described in terms of (1) the volcanology and eruptive palaeoenvironments; (2) petrology and origin of magma; and (3) active volcanism, including tephrochronology. Important volcanic episodes include: astonishingly voluminous mafic and felsic volcanic deposits associated with the Jurassic break-up of Gondwana; the construction and progressive demise of a major Jurassic to Present continental arc, including back-arc alkaline basalts and volcanism in a young ensialic marginal basin; Miocene to Pleistocene mafic volcanism associated with post-subduction slab-window formation; numerous Neogene alkaline volcanoes, including the massive Erebus volcano and its persistent phonolitic lava lake, that are widely distributed within and adjacent to one of the world's major zones of lithospheric extension (the West Antarctic Rift System); and very young ultrapotassic volcanism erupted subglacially and forming a world-wide type example (Gaussberg).

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