Preliminary U-Pb Detrital Zircon Ages from Tufiti di Tusa Formation (Lucanian Apennines, Southern Italy): Evidence of Rupelian Volcaniclastic Supply

U-Pb spot ages have been determined on detrital zircons from two samples of volcaniclastic arenites belonging to the Tufiti di Tusa Formation (TTF) outcropping in the Lucanian Apennines (Southern Italy). Many petrographic and geochemical studies have been performed on these sandstones with the aim of defining their detritus source. A new and precise evaluation of the mineralogical composition of metamorphic lithic fragments, together with U-Pb detrital zircon ages, helps to clarify the deposition age of these syn-sedimentary volcaniclastic sandstones and constrains their source areas. Volcaniclastic arenites consist of andesitic fragments and single minerals of plagioclases, clinopyroxenes, and hornblendes, while the metamorphic lithics are mainly fragments of blue amphibole-bearing micaschists, serpentinites, ophicalcites, phyllites, and medium-grade micaschists. Phaneritic plutonic fragments consist of quartz, feldspar, and micas. Carbonate components include biomicritic and biosparitic fragments. Eighty age data collected from 56 zircons reveal a wide age spectrum, ranging from Neoarchean to Rupelian (from 2712 ± 25 to 30 ± 1 Millions of years (Ma)). The age data show that in volcaniclastic sandstones there is evidence of ancient crystalline basements involved in Cadomian and Variscan orogenesis (ages from 2712 ± 25 Ma to ≈260 Ma), whereas the measured ages of 157 Ma testify the events of Pangea fragmentation and the ages between 78 and 67 Ma are related to subduction metamorphism connected to the Alpine orogenesis. Fifty percent of the estimated detrital zircon ages show a mean concordant age of 33 ± 1 Ma, they have been measured on idiomorphic crystals with undisturbed magmatic oscillatory zoning. These data reveal the true sedimentation age of Tufiti di Tusa sandstones at least at the sampled levels, coeval with that recorded in other Rupelian volcaniclastic successions outcropping in the Northern Apennines and in the Western Alps (e.g., Val d’Aveto-Petrignacola Formation, Ranzano Formation and Taveyannaz Sandstone). These data represent preliminary suggestions of the sedimentation age of the Tufiti di Tusa Formation and Rupelian paleogeography in the Western Mediterranean area. During Priabonian-Rupelian times, the volcanic calc-alkaline detritus linked to a widespread syn-sedimentary igneous activity on the hinterland terranes of the foredeep basins in the Apennine-Maghrebian orogen extended from north to south in the Western-Central Mediterranean area.

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Detrital zircon geochronology of metasedimentary rocks in the southern Omineca Belt, Canadian Cordillera

Canadian Journal of Earth Sciences ◽

10.1139/e91-112 ◽

1991 ◽

Vol 28 (8) ◽

pp. 1254-1270 ◽

Cited By ~ 42

Author(s):

Gerald M. Ross ◽

Randall R. Parrish

Keyword(s):

Detrital Zircon ◽

Bimodal Distribution ◽

Detrital Zircons ◽

Detrital Zircon Geochronology ◽

Early Proterozoic ◽

Metasedimentary Rocks ◽

Basement Rocks ◽

Two Samples ◽

Alberta Basin ◽

Detrital Zircon Ages

We address two problems of Cordilleran geology in this study using U–Pb dating of single detrital zircon grains from metasedimentary rocks: the provenance of the Windermere Supergroup, and the age and correlation of metasedimentary rocks within the Shuswap Complex that are at high metamorphic grade. Because some of these rocks are clearly of North American affinity, the ages of zircons provide indirect constraints on the age and distribution of continental basement from which the zircons were derived.A consistent pattern emerges from ages of about 50 grains from six rocks. Nearly all samples analyzed (48–53°N) are characterized by a bimodal distribution of zircon ages of 1.65–2.16 Ga and > 2.5 Ga, with a distinct lack of ages between 2.1 and 2.5 Ga. Exceptions to this pattern are young zircons from two samples, from Valhalla and Grand Forks – Kettle complexes of southeastern British Columbia, that have grains 1435 ± 35 and 650 ± 15 Ma, respectively. These younger grains are inferred to have been derived from magmatic rocks, and they have no obvious source in either the Canadian Shield or the Alberta subsurface basement to the east. The Early Proterozoic and Archean ages of detrital zircons resemble those of dated basement rocks beneath the Alberta Basin as well as basement exposed within the Cordilleran hinterland (gneisses of Thor–Odin, Frenchman Cap, and Malton regions). However, 2.1–2.4 Ga rocks that are extensive in the subsurface of northern Alberta are not represented in the inventory of detrital zircon ages presented in this paper.This pattern suggests that much of the Cordilleran basement between these latitudes is underlain by Archean crust of the Hearne–Wyoming provinces that may be mantled to the west by an orogenic–magmatic belt of Early Proterozoic (1.7–1.9 Ga) age which may largely have been parallel to the present Cordilleran orogen.

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U–Pb ages of detrital zircons in Cretaceous–Paleogene/Neogene kaolins within Eastern Dahomey and Niger Delta Basins (Nigeria) as provenance indicators

Scientific Reports ◽

10.1038/s41598-021-93453-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Olaonipekun Oyebanjo ◽

Georges-Ivo Ekosse ◽

John Odiyo

Keyword(s):

Detrital Zircon ◽

Niger Delta ◽

Detrital Zircons ◽

Oscillatory Zoning ◽

Northern Nigeria ◽

Magmatic Origin ◽

Pan African ◽

Parent Rocks ◽

Detrital Zircon Ages ◽

Primary Minerals

AbstractDetrital zircon grains within four (4) deposits including two (2) Cretaceous and two (2) Paleogene/Neogene kaolins in Nigeria were analysed using U–Pb LA-SFICP-MS to determine their provenance. The zircon textures were dominated by xenocrystic cores and oscillatory zoning in the Cretaceous and Paleogene/Neogene kaolins, respectively. The Th/U ratios obtained for the detrital zircon grains within the kaolins were predominantly within known values for rocks with magmatic origin. The age populations obtained for the detrital zircon grains were dominated by values from 529 to 978 Ma within the Neoproterozoic, followed by values from 1754 to 2497 Ma of the Paleoproterozoic. Detrital zircon ages obtained between 553.2 ± 6.2 and 583.5 ± 2.0 Ma represent part of the minimum provenance ages for the primary minerals that were kaolinised. The Cretaceous–Paleogene/Neogene kaolins were derived from parent rocks of Eburnean and Pan African ages within the Western and Northern Nigeria Basements.

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Chromosomal polymorphism in western Mediterranean populations of Drosophila subobscura

Genetics Research ◽

10.1017/s0016672300009575 ◽

1966 ◽

Vol 7 (2) ◽

pp. 149-158 ◽

Cited By ~ 25

Author(s):

Antonio Prevosti

Keyword(s):

Southern Italy ◽

Chromosomal Polymorphism ◽

Mediterranean Area ◽

Western Mediterranean ◽

Adaptive Significance ◽

Central Mediterranean ◽

Mediterranean Populations ◽

The North ◽

Latitudinal Clines ◽

North And South

1. The frequency of the chromosomal types of several western Mediterranean populations of D. subobscura, distributed in a zone running north–south, is analysed and compared with that from an Edinburgh (Knight, 1961) site at a similar meridian as the Mediterranean populations.2. North–south clines are found in the frequencies of several chromosomal types. Some types are more frequent in the north, decreasing gradually southwards; others show the reverse trend of variation.3. The comparison with a similar array of populations from Central Europe and the Central Mediterranean area, indicates that the chromosomal types more frequent in the northern populations are mostly the same, i.e. the standard orders. But chromosomal types with complex inversion orders are the most frequent in southern populations: in some chromosomes, different orders are predominant in Israel, southern Italy and southern Spain.4. The Pyrenees, acting as an ecological barrier, strongly influence the diversity of the populations north and south of the range. This result and the latitudinal clines support the adaptive significance of the chromosomal polymorphism in D. subobscura.5. The index of free recombination of the population from Malaga (in the south of Spain) is higher than in the populations from the northern Mediterranean area. D. subobscura apparently supports the claims of da Cunha & Dobzhansky (1954) and Carson (1955) that a higher level of chromosomal polymorphism occurs in the central areas of the distribution of a species.

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Algerian Olive Germplasm and Its Relationships with the Central-Western Mediterranean Varieties Contributes to Clarify Cultivated Olive Diversification

Plants ◽

10.3390/plants10040678 ◽

2021 ◽

Vol 10 (4) ◽

pp. 678

Author(s):

Kamel Atrouz ◽

Ratiba Bousba ◽

Francesco Paolo Marra ◽

Annalisa Marchese ◽

Francesca Luisa Conforti ◽

...

Keyword(s):

Mediterranean Basin ◽

Genetic Relationships ◽

Olive Tree ◽

Mediterranean Area ◽

Western Mediterranean ◽

Central Mediterranean ◽

Western Mediterranean Basin ◽

New Information ◽

Mediterranean History ◽

New Synonymy

Olive tree with its main final product, olive oil, is an important element of Mediterranean history, considered the emblematic fruit of a civilization. Despite its wide diffusion and economic and cultural importance, its evolutionary and phylogenetic history is still difficult to clarify. As part of the Mediterranean basin, Algeria was indicated as a secondary diversification center. However, genetic characterization studies from Maghreb area, are currently underrepresented. In this context, we characterized 119 endemic Algerian accessions by using 12 microsatellite markers with the main goal to evaluate the genetic diversity and population structure. In order to provide new insights about the history of olive diversification events in the Central-Western Mediterranean basin, we included and analyzed a sample of 103 Italian accessions from Sicily and, a set of molecular profiles of cultivars from the Central-Western Mediterranean area. The phylogenetic investigation let us to evaluate genetic relationships among Central-Mediterranean basin olive germplasm, highlight new synonymy cases to support the importance of vegetative propagation in the cultivated olive diffusion and consolidate the hypothesis of more recent admixture events occurrence. This work provided new information about Algerian germplasm biodiversity and contributed to clarify olive diversification process.

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Detrital zircon geochronology of Neoproterozoic to Permian miogeoclinal strata in British Columbia and Alberta

Canadian Journal of Earth Sciences ◽

10.1139/e98-071 ◽

1998 ◽

Vol 35 (12) ◽

pp. 1380-1401 ◽

Cited By ~ 51

Author(s):

George E Gehrels ◽

Gerald M Ross

Keyword(s):

British Columbia ◽

Detrital Zircon ◽

Isotopic Signature ◽

Detrital Zircons ◽

Detrital Zircon Geochronology ◽

Salmon River ◽

Western Canada Sedimentary Basin ◽

Cordilleran Margin ◽

Peace River Arch ◽

Detrital Zircon Ages

U-Pb ages have been determined on 250 detrital zircon grains from Neoproterozoic through Permian miogeoclinal strata in British Columbia and Alberta. Most of the grains in these strata are >1.75 Ga and are interpreted to have been derived from nearby basement provinces (although most grains were probably cycled though one or more sedimentary units prior to final deposition). Important exceptions are Ordovician sandstones that contain grains derived from the Peace River arch, and upper Paleozoic strata with detrital zircons derived from the Franklinian orogen, Salmon River arch (northwestern U.S.A.), and (or) Grenville orogen. These provenance changes resulted in average detrital zircon ages that become progressively younger with time, and may also be reflected by previously reported shifts in the Nd isotopic signature of miogeoclinal strata. In addition to the grains that have identifiable sources, grains of ~1030, ~1053, 1750-1774, and 2344-2464 Ma are common in our samples, but igneous rocks of these ages have not been recognized in the western Canadian Shield. We speculate that unrecognized plutons of these ages may be present beneath strata of the western Canada sedimentary basin. Collectively, our data provide a record of the ages of detrital zircons that accumulated along the Canadian Cordilleran margin during much of Paleozoic time. Comparisons between this reference and the ages of detrital zircons in strata of potentially displaced outboard terranes may help reconstruct the paleogeography and accretionary history of the Cordilleran orogen.

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U–Pb Dating and Hf Isotopes Analysis of Detrital Zircons of the Shanxi Formation in the Otuokeqi Area, Northwestern Ordos Basin

Geofluids ◽

10.1155/2021/6693005 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Jiaxuan Song ◽

Hujun Gong ◽

Jingli Yao ◽

Huitao Zhao ◽

Xiaohui Zhao ◽

...

Keyword(s):

Detrital Zircon ◽

North China ◽

Ordos Basin ◽

Detrital Zircons ◽

Oscillatory Zoning ◽

Edge Structure ◽

Material Recycling ◽

The North ◽

Upper Paleozoic ◽

The Ordos Basin

The Paleozoic strata are widely distributed in the northwest of the Ordos Basin, and the provenance attributes of the basin sediments during this period are still controversial. In this paper, the detrital zircon LA-MC-ICPMS U-Pb age test was conducted on the drilling core samples of the Shanxi Formation of the Upper Paleozoic in the Otuokeqi area of the Ordos Basin, and the provenance age and the characteristic of the Shanxi formation in the Otuokeqi area in the northwest were discussed. The cathodoluminescence image shows that the detrital zircon has a clear core-edge structure, and most of the cores have clear oscillatory zonings, which suggests that they are magmatic in origin. Zircons have no oscillatory zoning structure that shows the cause of metamorphism. The age of detrital zircon is dominated by Paleoproterozoic and can be divided into four groups, which are 2500~2300 Ma, 2100~1600 Ma, 470~400 Ma, and 360~260 Ma. The first two groups are the specific manifestations of the Precambrian Fuping Movement (2.5 billion years) and the Luliang Movement (1.8 billion years) of the North China Craton. The third and fourth groups of detrital zircons mainly come from Paleozoic magmatic rocks formed by the subduction and collision of the Siberian plate and the North China plate. The ε Hf t value of zircon ranges from -18.36 to 4.33, and the age of the second-order Hf model T DM 2 ranges from 2491 to 1175 Ma. The source rock reflecting the provenance of the sediments comes from the material recycling of the Paleoproterozoic and Mesoproterozoic in the crust, combined with the Meso-Neoproterozoic detrital zircons discovered this time, indicating that the provenance area has experienced Greenwellian orogeny.

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Late Paleozoic tectonism of the Bogda region in Chinese North Tianshan: Insights from sedimentary provenance analysis

10.5194/egusphere-egu21-16422 ◽

2021 ◽

Author(s):

Qian Wang ◽

Guochun Zhao ◽

Yigui Han ◽

Jinlong Yao

Keyword(s):

Detrital Zircon ◽

Detrital Zircons ◽

Late Paleozoic ◽

Provenance Analysis ◽

The North ◽

Tectonic Transition ◽

Isotopic Analyses ◽

Zircon Morphology ◽

Detrital Zircon Ages ◽

T Values

The Chinese North Tianshan (CNTS) extends E-W along the southern part of the Central Asian Orogenic Belt and has undergone complicated accretion-collision processes in the Paleozoic. This study attempts to clarify the late Paleozoic tectonism in the region by investigating the provenance of the Late Paleozoic sedimentary successions from the Bogda Mountain in the eastern CNTS by U-Pb dating and Lu-Hf isotopic analyses of detrital zircons. Detrital zircon U-Pb ages (N=519) from seven samples range from 261 &#177; 4 Ma to 2827 &#177; 32 Ma, with the most prominent age peak at 313 Ma. There are Precambrian detrital zircon ages (~7%) ranged from 694 to 1024 Ma. The youngest age components in each sample yielded weighted mean ages ranging from 272 &#177; 9 Ma to 288 &#177; 5 Ma, representing the maximum depositional ages. These and literature data indicate that some previously-assumed &#8220;Carboniferous&#8221; strata in the Bogda area were deposited in the Early Permian, including the Qijiaojing, Julideneng, Shaleisaierke, Yangbulake, Shamaershayi, Liushugou, Qijiagou, and Aoertu formations. The low maturity of the sandstones, zircon morphology and provenance analyses indicate a proximal sedimentation probably sourced from the East &#173;Junggar Arc and the Harlik-Dananhu Arc in the CNTS. The minor Precambrian detrital zircons are interpreted as recycled materials from the older strata in the Harlik-Dananhu Arc. Zircon &#603;Hf(t) values have increased since ~408 Ma, probably reflecting a tectonic transition from regional compression to extension. This event might correspond to the opening of the Bogda intra-arc/back arc rift basin, possibly resulting from a slab rollback during the northward subduction of the North Tianshan Ocean. A decrease of zircon &#603;Hf(t) values at ~300 Ma was likely caused by the cessation of oceanic subduction and subsequent collision, which implies that the North Tianshan Ocean closed at the end of the Late Carboniferous. This research was financially supported by the Youth Program of Shaanxi Natural Science Foundation (2020JQ-589), the NSFC Projects (41730213, 42072264, 41902229, 41972237) and Hong Kong RGC GRF (17307918).

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Detrital zircons from Late Paleozoic Ice Age sequences in Victoria Land (Antarctica): New constraints on the glaciation of southern Gondwana

Geological Society of America Bulletin ◽

10.1130/b35905.1 ◽

2021 ◽

Author(s):

Luca Zurli ◽

Gianluca Cornamusini ◽

Jusun Woo ◽

Giovanni Pio Liberato ◽

Seunghee Han ◽

...

Keyword(s):

Detrital Zircon ◽

Detrital Zircons ◽

Ice Age ◽

Late Paleozoic ◽

Lower Permian ◽

Petrographic Composition ◽

Ice Cap ◽

Victoria Land ◽

Two Samples ◽

Late Paleozoic Ice Age

The Lower Permian tillites of the Beacon Supergroup, cropping out in Victoria Land (Antarctica), record climatic history during one of the Earth’s coldest periods: the Late Paleozoic Ice Age. Reconstruction of ice-extent and paleo-flow directions, as well as geochronological and petrographic data, are poorly constrained in this sector of Gondwana. Here, we provide the first detrital zircon U-Pb age analyses of both the Metschel Tillite in southern Victoria Land and some tillites correlatable with the Lanterman Formation in northern Victoria Land to identify the source regions of these glaciogenic deposits. Six-hundred detrital zircon grains from four diamictite samples were analyzed using laser ablation−inductively coupled plasma−mass spectrometry. Geochronological and petrographic compositional data of the Metschel Tillite indicate a widespread reworking of older Devonian Beacon Supergroup sedimentary strata, with minor contribution from Cambro-Ordovician granitoids and meta-sedimentary units as well as Neoproterozoic metamorphic rocks. Euhedral to subhedral Carboniferous−Devonian zircon grains match coeval magmatic units of northern Victoria Land and Marie Byrd Land. This implies, in accordance with published paleo-ice directions, a provenance from the east-southeast sectors. In contrast, the two samples from northern Victoria Land tillite reflect the local basement provenance; their geochronological age and petrographic composition indicates a restricted catchment area with multiple ice centers. This shows that numerous ice centers were present in southern Gondwana during the Late Paleozoic Ice Age. While northern Victoria Land hosted discrete glaciers closely linked with the northern Victoria Land-Tasmania ice cap, the west-northwestward flowing southern Victoria Land ice cap contributed most of the sediments comprising the Metschel Tillite.

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Permo-Carboniferous conglomerates in the Trinity Peninsula Group at View Point, Antarctic Peninsula: sedimentology, geochronology and isotope evidence for provenance and tectonic setting in Gondwana

Geological Magazine ◽

10.1017/s001675681100080x ◽

2011 ◽

Vol 149 (4) ◽

pp. 626-644 ◽

Cited By ~ 26

Author(s):

JOHN D. BRADSHAW ◽

ALAN P. M. VAUGHAN ◽

IAN L. MILLAR ◽

MICHAEL J. FLOWERDEW ◽

RUDOLPH A. J. TROUW ◽

...

Keyword(s):

Antarctic Peninsula ◽

Detrital Zircon ◽

Tectonic Setting ◽

Detrital Zircons ◽

View Point ◽

Transport Distance ◽

Clastic Sedimentary ◽

Detrital Zircon Ages ◽

The Antarctic ◽

The Trinity

AbstractField observations from the Trinity Peninsula Group at View Point on the Antarctic Peninsula indicate that thick, southward-younging and overturned clastic sedimentary rocks, comprising unusually coarse conglomeratic lenses within a succession of fine-grained sandstone–mudstone couplets, are the deposits of debris and turbidity flows on or at the foot of a submarine slope. Three detrital zircons from the sandstone–mudstone couplets date deposition at 302 ± 3 Ma, at or shortly after the Carboniferous–Permian boundary. Conglomerates predominantly consist of quartzite and granite and contain boulders exceeding 500 mm in diameter. Zircons from granitoid clasts and a silicic volcanic clast yield U–Pb ages of 466 ± 3 Ma, 373 ± 5 Ma and 487 ± 4 Ma, respectively and have corresponding average εHft values between +0.3 and +7.6. A quartzite clast, conglomerate matrix and sandstone interbedded with the conglomerate units have broadly similar detrital zircon age distributions and Hf isotope compositions. The clast and detrital zircon ages match well with sources within Patagonia; however, the age of one granite clast and the εHf characteristics of some detrital zircons point to a lesser South Africa or Ellsworth Mountain-like contribution, and the quartzite and granite-dominated composition of the conglomerates is similar to upper Palaeozoic diamictites in the Ellsworth Mountains. Unlike detrital zircons, large conglomerate clasts limit possible transport distance, and suggest sedimentation took place on or near the edge of continental crust. Comparison with other upper Palaeozoic to Mesozoic sediments in the Antarctic Peninsula and Patagonia, including detrital zircon composition and the style of deformation, suggests deposition of the Trinity Peninsula Group in an upper plate basin on an active margin, rather than a subduction-related accretionary setting, with slow extension and rifting punctuated by short periods of compression.

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A Tarim-South China-North India connection in the periphery of Rodinia: Constraints from provenance of middle Neoproterozoic sedimentary rocks in the Altyn Tagh orogen, southeastern Tarim

10.5194/egusphere-egu2020-2108 ◽

2020 ◽

Author(s):

Qian Liu

Keyword(s):

South China ◽

Detrital Zircon ◽

Sedimentary Rocks ◽

Detrital Zircons ◽

Close Linkage ◽

North India ◽

Hf Isotopes ◽

Altyn Tagh ◽

Detrital Zircon Ages ◽

Rule Out

Locating Tarim during assembly and breakup of Supercontinent Rodinia remains enigmatic, with different models advocating a Tarim-Australia linkage or a location between Australia and Laurentia at the heart of unified Rodinia. In this study, zircon U-Pb dating results first revealed middle Neoproterozoic sedimentary rocks in the Altyn Tagh orogen, southeastern Tarim. These sedimentary rocks were deposited between ca. 880 and 750 Ma in a rifting-related setting slightly prior to breakup of Rodinia at ca. 750 Ma. A compilation of Neoproterozoic geological records indicates that the Altyn Tagh orogen in southeastern Tarim underwent ca. 1.0-0.9 Ga collision and ca. 850-600 Ma rifting related to assembly and breakup of Rodinia, respectively. In order to place Tarim in Rodinia, available detrital zircon U-Pb ages and Hf isotopes from Meso- to Neoproterozoic sedimentary rocks in relevant Rodinia blocks are compiled. Comparable detrital zircon ages (at ca. 0.9, 1.3-1.1, and 1.7 Ga) and Hf isotopes indicate a close linkage among southeastern Tarim, Cathaysia, and North India, but rule out a North or West Australian affinity for Tarim. In addition, detrital zircons from northern Tarim exhibit a prominent age peak at ca. 830 Ma with minor spectra at ca. 1.9 and 2.5 Ga but lack Mesoproterozoic ages, which are comparable to those from northern and western Yangtze. Together with comparable geological responses to assembly and breakup of Rodinia, a new Tarim-South China-North India connection is inferred in the periphery of Rodinia.

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