Ofioliti最新文献

{"title":"THE PERMIAN VOLCANICS OF CENTRAL ALBORZ: IMPLICATIONS FOR PASSIVE CONTINENTAL MARGIN ALONG THE SOUTHERN BORDER OF PALEOTETHYS","authors":"M. Delavari, A. Dolati, A. Mohammadi, Farzaneh Rostami","doi":"10.4454/OFIOLITI.V41I2.442","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V41I2.442","url":null,"abstract":"The Permian volcanics of Central Alborz (PVCA) crop out between the Ruteh and Nesen Formations in the Baladeh-Siahbisheh area. The volcanics are predominantly basaltic and plagioclase-phyric. Ferromagnesian minerals such as clinopyroxene and olivine are not modally abundant and sometimes are totally altered. Chemical composition of clinopyroxene is characterized by high TiO2 contents (4.9-7.2 wt.%). Based on whole rock geochemistry, the samples display sodic alkaline nature (Na2O = 3.7 to 7.8 wt.%). Chondrite-normalized rare earth element (REE) patterns are extremely LREE-enriched with (La/Yb)N of 8.3-20.5. Both normalized REE and multi-element diagrams represent ocean island basalt (OIB) characteristics. Modeling based on trace element values, and the content of some major elements reveal low partial melting degree (< 10%) of a deep garnet-bearing mantle source. As the samples geochemically show an intra-plate tectonomagmatic setting without subduction zone signatures, during the Permian (and earlier times), the Alborz area was possibly a passive continental margin along the southern border of Paleotethys. As a result, the Alborz Permian magmatism could have  been reasonably induced by an extensional tectonic regime along the northward-moving Cimmerian terranes during the early stages of Neotethys development.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2016-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70970292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TIMING OF LOWER CRUST GENERATION IN THE VOYKAR OPHIOLITE MASSIF, POLAR URALS, RUSSIA: U-Pb (LA-ICP-MS) DATA FROM PLAGIOGRANITE ZIRCONS","authors":"G. Queiroga, Maximiliano D. Martins, N. Kuznetsov, F. Chemale, I. Dussin, A. Pedrosa-Soares, K. Kulikova, M. P. Castro","doi":"10.4454/OFIOLITI.V41I2.443","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V41I2.443","url":null,"abstract":"The Uralide Orogen is one of the main Paleozoic belts formed during the assembly of Pangea. The present-day Urals (Uralian Mountains, N-S-trending through northern Eurasia) expose the relics of this Paleozoic orogen. The Voykar Massif, located at the Polar Urals, is an ophiolite assemblage composed mainly of mantle tectonite, gabbroic to ultramafic plutonic sequence and sheeted dikes with a MORB-type source. Geochronological data for this region show a wide range of ages and are mainly based on U-Pb zircon data, although some Rb-Sr and Sm-Nd are available. We present high-resolution U-Pb (LA-ICP-MS) analyses performed on zircon crystals extracted from a plagiogranite vein associated with a porphyritic dolerite dike. Magmatic zircon grains yielded a U-Pb age of 428.1±7.4 Ma, corresponding to the Wenlock Period (middle Silurian). This age suggests a late stage of oceanic crust generation in the Voykar basin. Different ages from plagiogranite and gabbroic bodies suggest that oceanic spreading lasted from ca. 490 to 425 Ma, i.e., at least 65 Ma or even longer, in the Voykar basin.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2016-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70970332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quartz fabric variations across the greenschist facies shear zone separating the Zermatt-Saas and combin ophiolitic zones, Upper Val Gressoney, Western Alps","authors":"E. Savignano, S. Reddy, J. Bridges, S. Mazzoli","doi":"10.4454/OFIOLITI.V41I2.444","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V41I2.444","url":null,"abstract":"The Gressoney Shear Zone (GSZ) consists of a ca. 500 m thick, intensely deformed rock panel located at the top of the high-pressure ophiolitic rocks of the Zermatt-Saas Zone in the Western Alps. This greenschist-facies shear zone accommodated multiple non-coaxial deformation events with contrasting kinematics. In this study, detailed field mapping and structural analysis were integrated with the study of crystallographic preferred orientation (CPO) from mylonites associated with the GSZ. Quartz CPO displays a systematic variation across the shear zone: moving from the basal shear zone boundary, the c-axes pattern changes from type II cross-girdle distribution, to an asymmetric pattern characterized by clustering of c-axes on one side of the Z-direction (inclined single girdle), to a central cluster in the Y-direction. The observed CPO patterns are consistent with increasing shear strain toward the basal contact, which probably controls the transition from broad peripheral maxima indicative of basal slip to an inclined single girdle with no maxima, which is indicative of prism slip, and finally an elongate single maximum at the girdle centre produced by a combination of prism and rhomb slip. Our results further indicate that basal slip is dominant in pure quartz domains, whereas with increasing proportion of second phases, prism slip is activated. These features confirm that CPOs obtained from the almost pure quartzites analysed in most published studies, and generally associated with the activation of distinct slip systems controlled by temperature, cannot be straightforwardly applied to the analysis of heterogeneous shear zones and/or polymineralic mylonites. From a regional point of view, the structures observed in the field and the fabric analyses are consistent with top-to-the-SE extension post-dating subduction-related high-pressure metamorphism and collisional nappe stacking in the studied sector of the Western Alps.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2016-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70970377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DEPLETED TO REFERTILIZED MANTLE PERIDOTITES HOSTING CHROMITITES WITHIN THE TUNCELI OPHIOLITE, EASTERN ANATOLIA (TURKEY): INSIGHTS ON THE BACK ARC ORIGIN","authors":"Okay Çimen, F. Toksoy-Köksal, Ayten Öztüfekçi-Önal, Alican Aktaǧ","doi":"10.4454/OFIOLITI.V41I1.439","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V41I1.439","url":null,"abstract":"The Tunceli Ophiolite, which represents the eastern part of the Izmir-Ankara-Erzincan Suture Belt (IAESB), hosts several chromite mines. The petrological characteristics of these deposits and their host rocks were investigated here for the first time. This ophiolite includes serpentinized peridotites, harzburgites, dunites, gabbros, sheeted dykes, pillow lavas and mudstones. The chromite occurrences are hosted in the mantle peridotites. The spinel group minerals in the ore and in ultramafic samples were sampled in seven different chromite mines (Yildirim, Aksu, Hasangazi, Atilla, Eskigedik, Isikvuran and Oymadal). The chromitite spinels display podiform characteristics. The Cr# = (0.39-0.89) and Mg# = values (0.43-0.74 ) of these spinel group minerals mainly correspond to magnesiochromite and chromite compositions. The silicate assemblage of the cpx-poor harzburgites include Mg-rich olivine (Fo91), enstatite and diopside. The occurrence of Ti-enriched secondary clinopyroxenes likely reflect refertilization processes which may have originated by interaction between Ti-rich melts and highly depleted peridotites. The average Cr2O3 (15.46 %wt) and ΣPGE (92.10 pbb) contents of the chromitites from the Tunceli ophiolite are lower than those of other chromitite-bearing ophiolites in Turkey. The consistent geochemical and mineral chemistry data from the mantle peridotites and chromitites within the Tunceli Ophiolite suggest formation in an intra-oceanic back-arc basin which may have been active during the closure of northern branch of the Neotethyan ocean.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2016-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70970090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogy, petrology and geochemistry of amphibolites from the Kalnik mt. (Sava Unit, North Croatia): implications for the evolution of north-westernmost part of the Dinaric-Vardar branch of Mesozoic Tethys","authors":"B. Šegvić, B. Lugović, Damir Slovenec, H. Meyer","doi":"10.4454/OFIOLITI.V41I1.441","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V41I1.441","url":null,"abstract":"This paper brings a first comprehensive set of mineralogical, petrological and geochemical data of amphibolites associated with mantle peridotites in the Upper Jurassic to mid Lower Cretaceous ophiolite melange of Kalnik Mt. in northern Croatia. This melange is emplaced in a Paleogene sedimentary succession. Metamorphic evolution of the amphibolites and the nature of their igneous protoliths are discussed in the frame of late history development of north-western branch of Dinaric-Vardar Tethys. Primary amphibolite assemblages consist of pargasite-magnesio-hornblende and oligoclase-bytownite (common amphibolite) + almandine-grossular-rich garnet (garnet amphibolites) + clinopyroxene (clinopyroxene amphibolites). Minimum equilibration temperature for the amphibole-plagioclase pairs was estimated at 660±40°C, whereas the peak conditions (790±20°C at 0.79 to 1.04 Gpa) were recorded in garnet amphibolite. Retrograde parageneses (albite, actinolite, clinozoisite, titanite, chlorite, pumpellyite, and ‘metamorphic vermiculite’) correspond to greenschist to sub-greenschist facies conditions. Protolith REE patterns match modern ocean ridge basalts (LaN/LuN = 0.51-0.82) whilst the normalized multi-element diagram shows slight negative HFSE anomalies (NbN/LaN = 0.44-0.90), diagnostic for a subduction-zone geochemical signature. Overall, geochemical data suggest back-arc basin (BAB) tholeiitic mafic extrusives (lack of Eu anomaly) and IAT-like cumulates (Eu positive anomaly) as amphibolite precursors. We propose that the protoliths of the Kalnik Mt. amphibolites represented a metamorphic sole formed at the expense of an oceanic crust originated at the ridge of a back-arc marginal basin. The metamorphism must have taken place during Tithonian (?) as inferred from the protolith age. According to the geological evidences the back-arc magmatic regime was active until the final closure of Mesozoic Tethys in Cretaceous by the obduction of Dinaric ophiolites onto the NW margins of Adria microplate, when part of the metamorphic sole must have been exhumed and obducted together with the rest of ophiolite sequence.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2016-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70970200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ASSOCIATION OF MORB AND SSZ OPHIOLITES ALONG THE SHEAR ZONE BETWEEN COLOURED MÉLANGE AND BAJGAN COMPLEXES (NORTH MAKRAN, IRAN): EVIDENCE FROM THE SORKHBAND AREA","authors":"M. Delavari, A. Dolati, M. Marroni, L. Pandolfi, E. Saccani","doi":"10.4454/OFIOLITI.V41I1.440","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V41I1.440","url":null,"abstract":"One of the largest worldwide accretionary wedges is exposed in the Makran region (SE Iran). The backstop of this accretionary wedge consists of an imbricate stack of continental and oceanic units, referred as North Makran domain. This domain is characterized by a km-thick shear zone, along which the metamorphic Bajgan Complex is thrust onto the Coloured Melange Complex. Along this shear zone two slices of ophiolites have been identified in the Sorkhband area. The upper tectonic slice consists of gabbros, whereas the lower tectonic one consists of mantle peridotites associated with dunites and chromitite ore deposits. Petrography and geochemistry of gabbros clearly indicate an N-MORB-type affinity, suggesting that they were generated at mid-ocean ridge setting. In contrast, mantle peridotites consist of harzburgites and depleted harzburgites, both showing geochemical features suggesting their genesis in a SSZ setting. The new data presented in this paper indicate that the slices of ophiolites from Sorkhband area derived from two different oceanic domains representing two different geodynamic settings. This occurrence provide new evidence that the boundary between the Coloured Melange and the Bajgan Complexes represents a first-order tectonic structure that played an important role in the geodynamic evolution of the Makran area.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2016-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70970181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magmatic and post-magmatic signatures of chromian spinels in podiform chromitites from the cheshmeh-bid chromitite deposit, khajeh-jamali ophiolitic massifs, Iran","authors":"A. Eslami, M. Ghaderi, W. Griffin, Sarah Gain, G. Grieco, J. González-Jiménez","doi":"10.4454/OFIOLITI.V40I2.437","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V40I2.437","url":null,"abstract":"Podiform bodies of high-Cr chromitite in the Cheshmeh-Bid chromitite deposit are located at the mantle-lower crust transition zone (MTZ) of the Late Cretaceous Khajeh-Jamali ophiolitic massifs, Iran. The unaltered core of chromian spinels has retained their magmatic composition but post magmatic sub-solidus re-equilibration changed significantly minor and trace elements (Ga, Ti, Ni, Zn, Co, Mn, V and Sc) composition. Minor disseminated chromites also occur and show lower chromite/silicate ratios than massive chromitites and were much more affected by the subsolidus mobility of minor and trace elements. Using the composition of the unaltered chromites preserved in the cores we have estimated the Al content and Fe/Mg ratios of their potential parental melts. The results of our computations show that Cheshmeh-Bid massive chromitites were crystallized from supra-subduction zone melts with boninitic affinity, consistent with the fact that minor and trace elements distributions in the studied chromite match well with that of chromian spinel from boninite lavas. The chromitites would have formed as a result of the reaction of migrating boninitic melts within host peridotite close to the MTZ in a supra-subduction zone setting. Post-magmatic processes (i.e., serpentinization) have only partially obliterated the magmatic fingerprints in some of the chromite grains.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2015-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70969968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The boeotian flysch revisited: New constraints on ophiolite obduction in central Greece","authors":"G. Nirta, G. Moratti, L. Piccardi, D. Montanari, R. Catanzariti, N. Carras, M. Papini","doi":"10.4454/OFIOLITI.V40I2.438","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V40I2.438","url":null,"abstract":"This paper reports new data on biostratigraphy, stratigraphy and syn-sedimentary deformation of the so-called “Boeotian Flysch” cropping out in key areas in Central Greece (Levadhia, Parnassus, Iti). Because of its age, sedimentary evolution and mechanisms of the syn-sedimentary deformation, the Boeotian Flysch represents a key element providing useful hints on the Cretaceous paleogeography reconstruction of the Dinaric-Hellenic Chain and in particular on the obduction at the Jurassic-Cretaceous transition in the eastern continental margin of the Adria plate. We provide here a new detailed study of different features of the Boeotian Flysch, with particular emphasis on reconstructing and dating its stratigraphy. In particular, we recognized two distinct turbiditic systems: the Lower Boeotian Flysch (Tithonian?-Aptian) and the Upper Boeotian Flysch (Cenomanian-Coniacian), which are separated by a main unconformity marking a sedimentary hiatus lasting from Aptian p.p. to Albian. By means of the improvement of the age, stratigraphy and deformation history of this syn-tectonic turbidite deposit, we therefore contribute to better define the chronology of the early phases of continental stage of obduction, and the following continental collision between Adria and Eurasia. The analyses of the collected data allowed us to propose for the Boeotian Flysch a deposition within an obduction-related foredeep basin associated with a flexural depression/flexural bulge due to crustal loading of westerly-directed ophiolite obduction.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2015-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70969623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geological and geochemical evidences for a Late Cretaceous continental arc in the Central Pontides, Northern Turkey","authors":"A. Ellero, G. Ottria, Kaan Sayıt, R. Catanzariti, C. Frassi, M. C. Göncüoğlu, M. Marroni, L. Pandolfi","doi":"10.4454/OFIOLITI.V40I2.436","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V40I2.436","url":null,"abstract":"In the Central Pontides (Northern Turkey), south of Tosya, a tectonic unit consisting of non-metamorphic volcanic rocks and overlying sedimentary succession is exposed inside a fault-bounded elongated block. It is restrained within a wide shear zone, where the Intra-Pontide Suture zone, the Sakarya Terrane and the Izmir-Ankara-Erzincan Suture zone are juxtaposed as result of strike-slip activity of the North Anatolian Shear Zone. The volcanic rocks are mainly basalts and basaltic andesites (with their pyroclastic equivalents) associated with a volcaniclastic formation made up of breccias and sandstones that are stratigraphically overlain by a marly-calcareous turbidite formation. The calcareous nannofossil biostratigraphy points to a late Santonian-middle Campanian age (CC17-CC21 Zones) for the sedimentary succession. The geochemistry of the volcanic rocks reveals an active continental margin setting as evidenced by the enrichment in Th and LREE over HFSE, and the Nb-enriched nature of these lavas relative to N-MORB. As highlighted by the performed arenite petrography, the occurrence of continent-derived clastics in the sedimentary succession supports the hypothesis of a continental arc-derived volcanic succession. Alternative geodynamic reconstructions are proposed, where this tectonic unit could represent a slice derived from the northern continental margin of the Intra-Pontide or Izmir-Ankara-Erzincan oceanic basins.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2015-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70969908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry of volcanic and subvolcanic rocks and biostratigraphy on radiolarian cherts from the Almopias ophiolites and Paikon Unit (Western Vardar, Greece)","authors":"M. Chiari, E. Saccani, V. Bortolotti, A. Photiades, G. Principi","doi":"10.4454/OFIOLITI.V40I1.432","DOIUrl":"https://doi.org/10.4454/OFIOLITI.V40I1.432","url":null,"abstract":"The Almopias and Paikon “sub-zones” in northern Greece represent the easternmost part of the Vardar Domain. Volcanic sequences in the Paikon sub- zone largely consist of calc-alkaline volcanic rocks with very minor normal-type (N-) mid-ocean ridge basalts (MORB) and boninites. These data confirm that the Paikon volcanics have originated in a volcanic arc setting developed during the Middle to Late Jurassic times on the westernmost continental margin of the European plate. The Almopias “sub-zone” consists of several ophiolite-bearing tectonic units showing a complex combination of different metamorphic, litho-stratigraphical, and age characteristics. The Liki, Nea Zoi, and Vrissi units (central Almopias) are ophiolitic melanges, the Mavrolakkos and Krania units (eastern Almopias) consist of volcanic sequences, and the Ano Garefi unit (eastern Almopias) includes serpentinized peridotites and overlying basaltic lavas. The Liki unit underwent metamorphism and deformation under amphibolite-facies condition and includes rocks showing N-MORB and low-K island arc tholeiitic affinities. The Nea Zoi unit incorporates N-MORBs of unknown age and Late Triassic calc-alkaline rocks. The Vrissi unit includes an incomplete volcanic sequence consisting of MORB-type volcanics linked with and crosscut by Middle-Late Jurassic arc-type volcanic rocks and dykes. The Mavrolakkos unit consists of sheeted dykes, lavas, and individual dykes with N-MORB affinity, which are crosscut by dykes showing volcanic arc affinity. The Krania unit consists of Middle-Late Jurassic N-MORB series tectonically associated with calc-alkaline volcanics and dykes. Basalts of the Ano Garefi unit have alkaline affinity, whereas dikes cutting the peridotites show enriched-type MORB chemistry. Our data show the occurrence in the Almopias units of Middle-Late Jurassic N-MORB lavas associated with overlying coeval volcanic arc-type lavas and/or intruded by volcanic arc-type dykes. A major point arising from this paper is that some of the Almopias ophiolitic units do not correlate with the other ophiolitic units in the Dinaride-Hellenide belt and some could correlate with the northernmost extension of the Vardar zone in the South Apuseni - Transyl- vanian ophiolitic belt in Romania.","PeriodicalId":54690,"journal":{"name":"Ofioliti","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2015-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70969741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}