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Sicily is a thick orogenic wedge formed by (1) the foreland (African) and its Sicilian orogen and (2) the thick-skinned, Calabrian-Peloritani wedge. The crust under central Sicily, from the Tyrrhenian margin to the coastline of the Sicily Channel, has been investigated by the multidisciplinary (SI.RI.PRO.) research project. The project dealt with the nature and thickness of the crust and depth and geometry of the Moho, which is essential in formulating subduction models and improving the knowledge of African and Tyrrhenian-European lithospheres. The results resolve features such as (1) the main orogenic wedge, (2) the very steep, NW-SE-trending regional monocline suggesting inflection of the foreland crust, (3) the deep Caltanissetta synform imaged, for the first time, to about 25 km, and (4) the top of the crystalline basement and the inferred crust-mantle boundary. The SI.RI.PRO. transect confirmed that the NNW-dipping, autochthonous Iblean platform of SE Sicily and its basement extends all the way into central Sicily. Further NW, towards the NNW end of the transect, a large uplift involves the Iblean platform and its underlying basement. The associated gravity anomaly is interpreted as the southern wedge edge of the Tyrrhenian mantle that splits the subducting Iblean-Pelagian (African) continental slab from an overlying synformal stack of allochthonous thrust sheets.

The Neoproterozoic Jiangnan orogenic belt delineates the suture zone between the Cathaysia and Yangtze blocks of the South China Craton. The western part of the belt, in the Longsheng region, consists of a disrupted mafic-ultramafic assemblage of pillow basalt, gabbro, diabase, and peridotite along with siliceous marble, ophicalcite, and jasper mixed with basalt. Significant talc deposits occur on the margins of the ultramafic bodies as well as in the transition zone between marble and basalt. Primary rock relations are largely overprinted by pervasive shearing, resulting in disruption of the assemblage into series of discontinuous blocks within a phyllite matrix. West-dipping thrust faults mark the eastern contact of blocks, and the overall succession has the appearance of a tectonic melange. U-Pb zircon age data from the gabbros and diabases yield crystallization ages of 867 ± 10, 863 ± 8, and 869 ± 9 Ma, with positive εHf(τ) values. The gabbro, basalt, serpentinite, and some talc samples display minor light rare earth element-enriched patterns with obvious depletion of Nb and Ta, indicating a subduction-related setting. The tuffaceous phyllite shows similar geochemical features. A few mafic rocks and the altered ultramafic rocks display mid-ocean ridge basalt (MORB) affinity. Overall lithostratigraphic relationships, age data, and geochemical signatures suggest a forearc setting that was imbricated and disrupted within an accretionary prism environment to form an ophiolitic melange. The pillow basalt, red jasper, and MORB-type mafic-ultramafic rocks within the melange occur as exotic blocks derived from the subducting oceanic plate, whereas the arc-type mafic rocks occur as autochthonous blocks, which are all exposed in a matrix of sandy and tuffaceous phyllite.

Late Ordovician (Hirnantian) glacio-marine deposits in the Central and Eastern Taurides and Southeast Anatolian Autochthon Belt (SAAB) in Turkey are mainly composed of diamictites, subrounded granitic pebbles, and rounded/subrounded lonestone pebbles. The granitic pebbles are dated as 576.5 ± 3.3, 576.7 ± 5.7, 598.4 ± 7.5, 717.5 ± 8.0, 789.5 ± 3.7, and 964.6 ± 4.6 Ma. The geochemical signatures and dated granitic pebbles in the Central and Eastern Taurides are interpreted to have been derived from the Late Neoproterozoic granitoids/metagranitic rocks of the Arabian-Nubian Shield (ANS; the Sinai Peninsula and the Eastern Desert of Egypt). The youngest 206Pb/238U ages in the diamictites (499.1 ± 4.2 Ma in the SAAB, 530.5 ± 5.3 Ma in the Eastern Taurides, and 562.5 ± 5.4 Ma in the Central Taurides) and in the lonestones (528.2 ± 4.5 Ma in the Central Taurides, 530.8 ± 5.2 Ma in the Eastern Taurides) indicate that detrital zircons were directly transported mainly from the northern margin of Gondwana and/or Arabia during the Late Ordovician, not from peri-Gondwanan parts of the European margin. Kernel/probability density diagrams of zircon ages from the lonestone pebbles in the Eastern and Central Taurides are interpreted as evidence for their derivation from Late/Middle Cambrian siliciclastic rocks in the Israeli part of the Sinai Peninsula. The provenance of detrital zircon populations in the diamictites in the Central and Eastern Taurides is directly correlated with magmatic activity of the Elat (Taba)–Feiran island arc, the Sa’al island arc, and the postcollisional magmatic suites in the Sinai Peninsula (Egypt). However, the corresponding successions in the SAAB have more abundant Late Cryogenian age components, suggesting the Ha’il/Afif/Ad Dawadimi/Ar-Rayn terranes of the eastern Arabian Shield as their provenance. These distinctive age patterns indicate that glacio-marine successions in the SAAB had different paleogeographic positions than their equivalent units in the Central and Eastern Taurides during deposition of the Late Ordovician glacio-marine units.

U-Pb laser ablation inductively coupled plasma mass spectrometry ages and Hf isotopes in zircons were used to constrain the nature of two geological units representative of the basement of the Central Cordillera of Colombia. Graphite-quartz-muscovite schists from the Cajamarca Complex show inherited detrital zircons supplied mostly from Late Jurassic (ca. 167 Ma), Ediacaran (ca. 638 Ma), and Tonian (Grenvillian; ca. 1000 Ma) sources. These marine volcanosedimentary deposits form an N-trending metamorphic belt in fault contact to the east with orthogneisses and amphibolites of the Tierradentro unit. Zircon U-Pb determinations of the Tierradentro rocks—previously interpreted as Grenvillian basement slices—yielded crystallization ages between 271 and 234 Ma. Initial Hf data reveal that the Tierradentro unit shares isotopic characteristics similar to other Permo-Triassic rocks of the Central Cordillera. In contrast, inherited detrital zircons from the Jurassic metasedimentary rocks suggest that their sources are distinct from the plutonic rocks that crop out in the Central Cordillera with Jurassic crystallization ages. Large xenoliths of the Tierradentro unit within the Ibagué batholith indicate that the granodioritic magma mostly intruded a Permo-Triassic basement possibly by exploiting the Otú-Pericos fault. The Jurassic metasedimentary belt is correlated further south with a similar sequence in the Ecuadorian Andes named Salado terrane.

In the region of the Caucasus considered herein two large structural complexes have been identified: an autochthone, including the Gagra-Java zone (GJZ) of the Greater Caucasus fold-and-thrust belt, the Kura foreland basin (KFB), and an allochthone consisting of the Utsera-Pavleuri, Alisisgori-Chinchvelta, Sadzeguri- Shakhvetila, Zhinvali-Pkhoveli nappes and Ksani-Arkala parautochthone. The nappes are established on the basis of paleogeographic reconstructions, structural data, as well as drilling and geophysical data. The leading mechanism for the nappe formation is the advancement to the north and the underthrusting of the autochthone under the Greater Caucasus (A-type subduction). The nappes were formed mainly in the Late Alpine time (Late Eocene–Early Pliocene) and include only the sedimentary cover of the Earth’s crust (thin-skinned nappes). However the basal detachment (décollement) of the nappes, according to seismic data, penetrates deeply and cuts the pre-Jurassic crystalline basement, and even the entire Earth’s crust representing thick-skinned deformation. The total horizontal displacement of the flysch nappes of the southern slope of the Greater Caucasus in their eastern (Kakhetian) part is 90–100 km. While, considering the folding of the entire Greater Caucasus, the total transverse shortening of the Earth‘s crust within its limits is equal to 190–200 km.

The δ13C profile from an interval of the Martin Point section in western Newfoundland (Canada) spans the upper Furongian (uppermost Cambrian). The interval (~90 m) is a part of the Green Point Formation of the Cow Head Group and consists of the Martin Point (lower) and the Broom Point (upper) members. It is formed of slope marine carbonates alternating with shales (rhythmites) and conglomeratic interbeds. The preservation of the investigated micritic carbonates was meticulously evaluated by multiple petrographic and geochemical screening tools. The δ13C and δ18O values (−0.5 ± 0.8 ‰VPDB and −7.1 ± 0.3 ‰VPDB, respectively) exhibit insignificant correlation (R2 = 0.002) and similarly the correlation of δ13C values with their Sr and Mn counterparts, which supports the preservation of at least near-primary δ13C signatures that can be utilized to construct a reliable high-resolution carbon-isotope profile for global correlations. The δ13C profile exhibits two main negative excursions, a lower broad excursion (~3 ‰) that reaches its maximum at ~70 m below the Martin Point / Broom Point members boundary and an upper narrow excursion (~2.5 ‰) immediately below the same boundary. The lower excursion can be correlated with the global latest Furongian HERB event (TOCE), which is also recognized in the C-isotope profile of the GSSP boundary section at Green Point whereas the upper excursion matches with that of the Cambrian‒Ordovician boundary in the same section. The peak of the HERB δ13C excursion is correlated with positive shifts on the Th/U and Ni profiles (redox and productivity proxies).

Three paleogeographic scenarios have been proposed for the Mesozoic volcano-sedimentary successions that compose the Guerrero terrane, western Mexico. In the type 1 scenario, the Guerrero terrane is an exotic Pacific arc accreted to nuclear Mexico by the consumption of a pre-Cretaceous oceanic basin, named Arperos Basin. The type 2 scenario considers the Guerrero terrane as a fringing multiarc system, accreted by the closure of pre-Cretaceous oceanic basin substrates at multiple subduction zones with varying polarities. In the type 3 scenario, the Guerrero terrane is interpreted as a North American west-facing para-autochthonous arc, which was drifted in the paleo-Pacific domain by the opening of the Cretaceous back-arc oceanic Arperos Basin. To test these reconstructions, we present here a combined study that includes geologic mapping, stratigraphy, U-Pb geochronology, and sandstone provenance data from the Arperos Basin in the Sierra de Guanajuato, central Mexico. Our data document that the Arperos Basin developed in a back-arc setting and evolved from continental to open oceanic conditions from the Late Jurassic to the Early Cretaceous. Sandstone provenance analysis shows an asymmetric distribution of the infill sources for the Arperos Basin: continent-recycled sedimentary rocks were deposited along its northeastern side, whereas magmatic arc-recycled clastic rocks developed at its southwestern side. Such asymmetric distribution closely fits with sedimentological models proposed for present-day continent-influenced back-arc basins. On the basis of this evidence, we favor a type 3 scenario for the Guerrero terrane, which is then considered to represent a detached slice of the Mexican leading edge that drifted in the paleo-Pacific domain during back-arc extension and subsequently accreted back to the Mexican craton.

The Qin-Fang Trough, South China, trends northeast-southwest, orthogonal to the adjoining southern margin of the craton. The Devonian strata within the trough are unconformable on late Neoproterozoic units of the Yunkai Massif, indicating that strata within the trough are autochthonous. U-Pb ages and Hf isotope compositions of detrital zircons from the Silurian to Devonian succession are consistent with derivation from the massif. In comparisons of our data with those from equivalent units in the Ailaoshan Belt and Hainan Island, detrital zircons from the Silurian strata show similar age distributions and Hf isotope compositions, indicating that the three areas shared a common source and were adjacent to each other during the Silurian. In contrast, the age distributions of detrital zircons preserved in Devonian strata in the Qin-Fang area are different from those of equivalent units in the Ailaoshan Belt. This, along with the absence of Devonian strata on Hainan Island, suggests that the Qin-Fang area had separated from the Ailaoshan Belt by the Devonian. This change is linked to opening of the Ailaoshan Ocean, which was synchronous with expansion of the Qin-Fang Trough and the adjoining Youjiang Basin into epicontinental basins during the Devonian and Carboniferous. Combining these findings with temporal and spatial correlations, we conclude that the Qin-Fang Trough originated as an aulacogen: a “failed” rift of a three-armed rift system, with the other two rift arms evolving into the Ailaoshan Ocean during the opening of Paleo-Tethys. The Ailaoshan Ocean was an Atlantic-type oceanic basin with rifting commencing in the Early Silurian.

Flysch-type, syn-orogenic deposits of Carboniferous age occur in relation to the emplacement of a large allochthonous nappe stack in the Variscan belt of NW Iberia. New U–Pb age populations of detrital zircons obtained using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are considered together with others from previously dated samples to establish the relationships between sedimentation and thrusting. The age populations of four syn-orogenic formations are compared with those of the pre-orogenic sequence in the Autochthon and Parautochthon, representing the Gondwanan passive margin, and in the Allochthon, formed by peri-Gondwanan and oceanic terranes. In addition, a new structural study has been carried out to understand the relationships between the syn-orogenic deposits and the development of Variscan structures. The aims are to identify the sources of sediments and to establish the relationship between Variscan structural evolution and syn-orogenic sedimentation. Development of a forebulge outwards from the allochthonous front, deduced from the structural study, suggests the existence of depocentres that hosted the syn-orogenic sediments. Together with the trend shown by the more recent zircons in each formation, that are younger towards the external zones, the data suggest that sedimentation occurred in progressively migrating depocentres formed in front of the allochthonous wedge during its emplacement. The zircon age populations point to the Allochthon as the main source of detritus for the syn-orogenic basins, with perhaps a limited participation of the Parautochthon and Autochthon in the younger formations.

Three models are evaluated for restoring basement rocks coring tectonic windows (Window-Basement) in the Scandinavian Caledonides; parautochthonous (Model I) and allochthonous (models II/III), with initial imbrication of the Window-Basement post-dating or pre-dating, respectively, that in the external imbricate zone (Lower Allochthon). In Model I, the Window-Basement comes from the eastern margin of the basin now imbricated into the Lower Allochthon, while in models II/III it comes from the western margin. In Model II, the Window-Basement formed a basement-high between Tonian and Cryogenian sediments imbricated into the Middle and Lower allochthons; in Model III deposition of the Lower Allochthon sediments commenced in Ediacaran times. Balanced cross-sections and branch-line restorations of four transects (Finnmark–Troms, Västerbotten–Nordland, Jämtland–Trøndelag, Telemark–Møre og Romsdal) show similar restored lengths for the models in two transects and longer restorations for models II/III in the other transects. Model I can result in c. 280 km wide gaps in the restored Lower Allochthon, evidence for which is not seen in the sedimentology. The presence of <3 km thick alluvial-fan deposits at the base of the Middle Allochthon indicates proximal, rapidly uplifting basement during Tonian–Cryogenian periods, taken as the origin of the Window-Basement during thrusting in models II/III. Model I requires multiple changes in thrusting-direction and predicts major thrusts or back-thrusts, currently unrecognized, separating parts of the Lower Allochthon; neither are required in models II/III. Metamorphic data are consistent with models II/III. Despite considerable along-strike structural variability in the external Scandinavian Caledonides, models II/III are preferred for the restoration of the Window-Basement.