The basal part Modino Unit Succession under the belt-foredeep system of the Northern Apennines (Italy)

The Modino Unit turbidite system of the Northern Apennines foreland basin provides an excellent opportunity to study the sedimentary and structural variations within the context of spatial and temporal distribuition of source rocks during the evolution of foreland basins. The substrate of this Unit was interpreted as a stratigraphic-structural mélange (Plesi et al., 2000), the expression of polyphase tectonic phases of Cretaceous-Eocene accretion that have affected the external part of Ligurian and Subligurian domain. In this article we present the preliminary data of different stratigraphic sections outcropping in Tuscan and Emilian regions, with particulary attention to the lower part of Modino Unit Succession, of pre-Ligurian stage, unconformably deposited at the top of the Ligurian and Subligurian substrate, composed by Fiumalbo Shale Fm. and Marmoreto Marl Fm. The tectonic setting of this Unit is complex and necessitated the use of stratigraphical, biostratigraphical and petrographical studies to achieve this goals. The Modino Unit succession is composed by three different formations: The Fiumalbo Shale Fm. followed in some sections of coarse breccia deposits that cover the substrate (Riccovolto Breccia) are made up of mostly red and green shales with intercalations of limestone and turbidite-like sandstones beds more or less extensive (Rio Acquicciola Sandstones Auctt. or M. Sassolera Sandstones Auctt.). The Marmoreto Marl Fm. are characterized by fine emipelagic sediments, have a massive structure (with rare thin layers of fine sandstones). The Monte Modino Sandstone Fm. are constituted by one or more sequences of turbidite facies with quite variable vertically and laterally . Their deposition occurs preferentially in the middle and front al part of the prism and is quickly interrupted, on its southwestern margin, by the thrust belt materials. From this reason the axis of sedimentation moving outwards. A petrographical study on turbidite-like sandstone beds in Fiumalbo Shale Fm., show a petrofacies characterized by a modal composition of Q48F27L+CE25, according with the composition of Monte Modino Sandstone of this study, while shows different composition in the Fine-Grained Rock Fragments Compositional Mode (LmLvLs plot). The sandstones in Fiumalbo Shale Fm., are composed by different tipology of fine grained lithic fragments, and its composition changes strata-strata in the same stratigraphic sections. The fine grained lithic fragments are composed by dominating metamorphic origin clasts and ophiolithic rock fragment associated with unmetamorphic radiolaritic fragments, The biostratigraphical analysis indicate that the age of theese formations is comprised between Lutetian and Chattian ages. These formations reflect a slope environment, with quite deep and with a strong affinity to Epiligurian sections, which resemble the coeval succession Monte Piano-Ranzano and their sedimentation environment reflects a time and an area of major physiographic expression of the prism. The composition of this arenites is interpreted as being controlled mainly by synsedimentary tectonics connected with the evolution of an accretionary prism east vergent. This composition reflects the different stages of the process of accretion and is the expression of the different sedimentary environments that were gradually generating. The lower part of Modino Unit succession seems to be supplied by two different source areas, the classic Alpine source area and a more proximal "Liguride derived" source, maybe located in the proto-appenninic wedge

Evidences for a Late Cretaceous continental arc in the Central Pontides: new insights on alternative geodynamic reconstructions for the Neotethys in Northern Turkey

The Intra-Pontide Suture Zone (IPSZ) is the less known one among the suture zones present in Turkey. The IPSZ is well exposed along the Daday-Arac-Kursunlu and Tosya – Emirköy geotraverses where several tectonic units can be recognized. Most of these units are characterized by the occurrence of basic rocks reflecting distinct tectonic origins and geochemical signatures. The study of the basic rocks emerges as an important tool for the geodynamic reconstruction as it can reveal the occurrence of of different types of oceanic basins, the development of a magmatic arc or the presence of rifting-related magmatism. The study of the geotraverses indicates that the imbricate stack of the IPSZ consists of four distinct tectonic units whose successions bear basic rocks: the Aylı Dağ ophiolite Unit, the Arkot Dağ Mèlange and two metamorphic units, referred to as Daday and Devrekani Units. This imbricate stack is probably the result of several episodes of out-of-sequence thrusts that affected the whole IPSZ. The Aylı Dağ Unit includes an about 5 km-thick ophiolite sequence topped by the middle Bathonian to early Callovian radiolarian cherts. In addition, a metamorphic sole is present at the base of the serpentinized peridotites. The geochemical evaluation of pillow-basalts and dykes highlights subduction-related characteristics, similar to IAT- and BABB-type lavas generated above intra-oceanic subduction systems. The Arkot Dağ Mèlange consists of an assemblage of slide-blocks, with different size and lithology, enclosed in a Late Santonian sedimentary matrix. The slide-blocks also include ophiolitic lithologies, mainly represented by basalts, but gabbros and peridotites are also found. The slide-blocks of basalts display affinites to IAT- and BABB-type magmas, signifying the involvement of subduction component, whereas no MORB-like basalt have been found. The Daday unit is characterized by metasedimentary and metabasic rocks deformed under blueschist to subgreenschist metamorphic facies conditions. The metasedimentary rocks include mica-bearing schists, fine-grained marbles and black quartzites. The metabasic lithologies, on the other hand, comprise actinolite-bearing schists and Naamphibole- bearing varieties possibly derived from basaltic and gabbroic protoliths. The metabasic rocks have a wide range of chemical compositions, displaying N-MORB-, E-MORB-, OIB- BABB- and IAT-type signatures. The Devrekani Unit is represented by an assemblage of amphibolites, marbles and micaschists showing a metamorphic climax developed under upper amphibolite facies in the Late Jurassic time. The amphibolites display EMORB-, OIB- BABB- and IAT-type signatures. The geochemical signature of the studied basic rocks provide the evidence that all the basic rocks from the tectonic units of IPSZ are derived by a supra-subduction zone. This finding can provide new nsights for the recostruction of the sgeodynamic history of the Intra-Pontide domain

Rock magnetic signature of the Middle Eocene Climatic Optimum (MECO) event in different oceanic basins

The Middle Eocene Climatic Optimum (MECO) event at ~40 Ma was a greenhouse warming which indicates an abrupt reversal in long-term cooling through the middle Eocene. Here, we present environmental and rock magnetic data from sedimentary successions from the Indian Ocean (ODP Hole 711A) and eastern NeoTethys (Monte Cagnero section - MCA). The high-resolution environmental magnetism record obtained for MCA section shows an interval of increase of magnetic parameters comprising the MECO peak. A relative increase in eutrophic nannofossil taxa spans the culmination of the MECO warming and its aftermath and coincides with a positive carbon isotope excursion, and a peak in magnetite and hematite/goethite concentrations. The magnetite peak reflects the appearance of magnetofossils, while the hematite/goethite apex are attributed to an enhanced detrital mineral contribution, likely related to aeolian dust transported from the continent adjacent to the Neo-Tethys Ocean during a drier, more seasonal MECO climate. Seasurface iron fertilization is inferred to have stimulated high phytoplankton productivity, increasing organic carbon export to the seafloor and promoting enhanced biomineralization of magnetotactic bacteria, which are preserved as magnetofossils during the warmest periods of the MECO event. Environmental magnetic parameters show the same behavior for ODP Hole 711A. We speculate that iron fertilization promoted by aeolian hematite during the MECO event has contributed significantly to increase the primary productivity in the oceans. The widespread occurrence of magnetofossils in other warming periods suggests a common mechanism linking climate warming and enhancement of magnetosome production and preservation

Multiple Orbitoides d’Orbigny lineages in the Maastrichtian? Data from the Central Sakarya Basin (Turkey) and Arabian Platform successions (Southeastern Turkey and Oman)

The standard reconstruction of species of Orbitoides d’Orbigny into a single lineage during the late Santonian to the end of the Maastrichtian is based upon morphometric data from Western Europe. An irreversible increase in the size of the embryonic apparatus, and the formation of a greater number of epi-embryonic chamberlets (EPC) with time, is regarded as the main evolutionary trends used in species discrimination. However, data from Maastrichtian Orbitoides assemblages from Central Turkey and the Arabian Platform margin (Southeastern Turkey and Oman) are not consistent with this record. The Maastrichtian Besni Formation of the Arabian Platform margin in Southeastern Turkey yields invariably biconvex specimens, with small, tri- to quadrilocular embryons and a small number of EPC, comparable to late Campanian Orbitoides medius (d’Archiac). The upper Maastrichtian Taraklı Formation from the Sakarya Basin of Central Turkey contains two distinct, yet closely associated forms of Orbitoides, easily differentiated by both external and internal features. Flat to biconcave specimens possess a small, tri- to quadrilocular embryonic apparatus of Orbitoides medius-type and a small number of EPC, whereas biconvex specimens possess a large, predominantly bilocular embryonic apparatus, and were assigned to Orbitoides ex. interc. gruenbachensis Papp–apiculatus Schlumberger based on morphometry. The flat to biconcave specimens belong to a long overlooked species Orbitoides pamiri Meriç, originally described from the late Maastrichtian of the Tauride Mountains in SW Turkey. This species is herein interpreted to be an offshoot from the main Orbitoides lineage during the Maastrichtian, as are forms that we term Orbitoides ‘medius’, since they recall this species, yet are younger than normal occurrence with the accepted morphometrically defined lineage. The consistent correlation between the external and internal test features in O. pamiri implies that the shape of the test is not an ecophenotypic variation, but appears to be biologically controlled. We, therefore, postulate that more than one lineage of Orbitoides exists during the Maastrichtian, with a lineage that includes O. ‘medius’ and O. pamiri displaying retrograde evolutionary features

Genome analysis and avirulence gene cloning using a high-density RADseq linkage map of the flax rust fungus, Melampsora lini

Agroinfiltration of avirulence gene constructs. The response of flax cultivars and near-isogenic lines to expression of avirulence gene candidates (AvrM14-A, AvrM14-B and AvrL2-A) using Agrobacterium tumefaciens-mediated transient transformation. (PDF 2637 kb