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In the mid-1850s, Thomas Henry Huxley, who coined the term 'coccolith', described their presence in oceanic sediments dredged from the sea floor. Subsequent recognition of their occurrence in the Upper Cretaceous English Chalk, largely unconsolidated pelagic sediment, and similar, more lithified limestones in the Jurassic of the Alps, led to their being considered major rock-forming elements through much of geological time, although they are now known to be limited to the Late Triassic–Recent interval. Unlike Charles Darwin, who did not travel abroad following the voyage of the Beagle, Huxley made a number of trips to Italy and Switzerland and is recorded as a guest in the exclusive Hotel Kursaal Maloja in the Engadin in 1893. While staying there, he made a number of excursions on foot and his presence was thought significant enough that it is recorded in an inscribed granitic stone tablet, erected in 1896, describing him as'the illustrious writer and naturalist'. His rambles would have led him past outcrops of tectonically emplaced true oceanic calcareous sediment of Early Cretaceous age, here shown to have originally contained coccoliths that were largely destroyed under the imprint of Alpine metamorphism of sub-greenschist to greenschist facies. To this extent, Huxley could have come close to recognizing true oceanic sediments exposed on land, but the dissimilarity between these Swiss Alpine deposits and the friable English Chalk would not obviously have led to the investigation of the former for the organisms he had christened as 'coccoliths'. [ABSTRACT FROM AUTHOR]

In 1890, former students of Arnold Guyot at the University of Neuchàtel dedicated a 'large glacial boulder from Neuchâtel' to his memory, now in front of Guyot Hall at Princeton University. We established that this block originated with all certainty from Upper Carboniferous conglomerates of the Salvan–Dorénaz Basin, the relics of which crop out in the Alps of western Switzerland and eastern France. During the Last Glacial Maximum, the boulder travelled from the lower Rhône Valley on the back of the Pleistocene Rhône Glacier to Neuchâtel from where, later, it crossed the Atlantic and was transported to Princeton. Guyot's name is familiar to geologists because of the term 'guyot', introduced 1946 by Harry Hess for 'curious flat-topped peaks scattered over millions of square miles in the Pacific basin', many of which are now known to represent drowned carbonate platforms. [ABSTRACT FROM AUTHOR]

Tectono-sedimentary breccias, known as ophicalcites, overlie serpentinised peridotites at a Jurassic ocean–continent transition along the Penninic-Austroalpine transition in the Eastern Alps of Switzerland. Deformation of the exhumed mantle rocks and breccia formation occurred under decreasing temperatures and along low-angle detachment faults exposing the mantle rocks at the sea floor and was coupled with hydrothermal activity and carbonation of the serpentinites at shallow depth and/or at the sea floor. Carbon isotopes in the ophicalcites persistently show marine values; however, the interpretation of oxygen-isotope values remained controversial: are they related to Jurassic hydrothermal activity or do they reflect Alpine metamorphic overprint? Here we discuss recent interpretations that relate oxygen isotope values measured in ophicalcites exclusively to Jurassic hydrothermal activity; to this end we use data that we earlier obtained along a north–south profile across Graubünden (eastern Switzerland). We revisited the sites of controversial interpretation along a north–south profile in eastern Switzerland. Along this profile, oxygen isotope values in ophicalcites and overlying pelagic sediments, up to 25 my younger than the ophicalcites, show identical values and become systematically lower with increasing Alpine metamorphism; they strongly deviate from values in ophicalcites and pelagic sediments measured along the Mid-Atlantic Ridge or ancient Atlantic ocean-continent transitions as e.g. in the Iberia–Newfoundland transect. The oxygen-isotope values measured in Alpine ophicarbonates thus reflect isotopic resetting during the Alpine orogeny, related to fluid-rock interaction during regional metamorphism. Hydrothermal processes that accompanied the formation of ophicalcites are not disputed; however, they cannot be traced by oxygen isotope geochemistry. [ABSTRACT FROM AUTHOR]

They do not reflect the temperatures of carbonation of the serpentine host rocks or the formation of calcite in veins and cements or of marine biogenic calcite in pelagic sediments associated with the ophicalcites. However, at other localities like Arosa, the ophicalcites co-occur with basalts, similar to the ophicalcites at Falotta (Platta Nappe). 4), with the oxygen isotope values from Marmorera-Cotschens (Coltat et al. [4]) added Coltat et al. ([5]) distinguish between "cooler ophicalcites" in the South-Penninic nappes and the ophicalcites of the Platta Nappe. [Extracted from the article]

The Upper Cretaceous (Campanian–Maastrichtian) bioclastic wedge of the Orfento Formation in the Montagna della Maiella, Italy, is compared to newly discovered contourite drifts in the Maldives. Like the drift deposits in the Maldives, the Orfento Formation fills a channel and builds a Miocene delta‐shaped and mounded sedimentary body in the basin that is similar in size to the approximately 350 km2 large coarse‐grained bioclastic Miocene delta drifts in the Maldives. The composition of the bioclastic wedge of the Orfento Formation is also exclusively bioclastic debris sourced from the shallow‐water areas and reworked clasts of the Orfento Formation itself. In the near mud‐free succession, age‐diagnostic fossils are sparse. The depositional textures vary from wackestone to float‐rudstone and breccia/conglomerates, but rocks with grainstone and rudstone textures are the most common facies. In the channel, lensoid convex‐upward breccias, cross‐cutting channelized beds and thick grainstone lobes with abundant scours indicate alternating erosion and deposition from a high‐energy current. In the basin, the mounded sedimentary body contains lobes with a divergent progradational geometry. The lobes are built by decametre thick composite megabeds consisting of sigmoidal clinoforms that typically have a channelized topset, a grainy foreset and a fine‐grained bottomset with abundant irregular angular clasts. Up to 30 m thick channels filled with intraformational breccias and coarse grainstones pinch out downslope between the megabeds. In the distal portion of the wedge, stacked grainstone beds with foresets and reworked intraclasts document continuous sediment reworking and migration. The bioclastic wedge of the Orfento Formation has been variously interpreted as a succession of sea‐level controlled slope deposits, a shoaling shoreface complex, or a carbonate tidal delta. Current‐controlled delta drifts in the Maldives, however, offer a new interpretation because of their similarity in architecture and composition. These similarities include: (i) a feeder channel opening into the basin; (ii) an excavation moat at the exit of the channel; (iii) an overall mounded geometry with an apex that is in shallower water depth than the source channel; (iv) progradation of stacked lobes; (v) channels that pinch out in a basinward direction; and (vi) smaller channelized intervals that are arranged in a radial pattern. As a result, the Upper Cretaceous (Campanian–Maastrichtian) bioclastic wedge of the Orfento Formation in the Montagna della Maiella, Italy, is here interpreted as a carbonate delta drift. [ABSTRACT FROM AUTHOR]

Sparse isolated pebbles and cobbles of extraformational lithologies are occasionally found in fine-grained deep-water sediments. In the Middle and Upper Liassic deep-water marly limestones and marlstones of Rosso Ammonitico facies (Morbio and Rosso Ammonitico Lombardo Formations) in the western Southern Alps, Lombardy and Ticino, outsized 'exotic' clasts of volcanic and basement rocks occur sporadically. The clasts, of pebble size, are typically rounded. The rhyolitic volcanic clasts can be related to the Permian volcanic succession of the western Southern Alps, from which they must have been reworked; a quartzite pebble is obviously derived from the Hercynian basement. The clasts are best interpreted, in analogy to other occurrences, as dropstones transported to the site of final deposition by drift wood that occasionally occurs in the pelagic sediments. The only possible source area must be situated to the west of Lago Maggiore where the Permian volcanic suite was exposed in a fault block uplifted in the course of latest Triassic-Early Jurassic rifting. [ABSTRACT FROM AUTHOR]

In the Argolis, the Basal Sequence, constituting the eastern Pelagonian margin which bordered the Maliac-Vardar oceanic domain, includes shallow-water carbonates of Late Triassic-Early Jurassic, condensed pelagic limestones of Early-Middle Jurassic, radiolarian cherts of late Middle-Late Jurassic age and siliceous mudstones and sandstones rich in ophiolite fragments. Up-section, coarse breccias, including clasts of boninites derived from the ophiolite obducted onto the Pelagonian margin in Late Jurassic times crop out. Near Angelokastron a small quarry exposes pervasively sheared dark reddish-brown, radiolarian-bearing cherty shales with disrupted fragments of chert and chert nodules impregnated by ferro-manganese oxides. These shales occur in the footwall of a thrust bringing them into contact with the Pantokrator Limestone of the Basal Sequence. We collected more than 30 samples of the chert fragments and the shaly matrix. Thirteen nodules and one matrix sample yielded determinable radiolarians. Low to non-detectable concentrations of trace metals such as Co, Cr, Cu, Ni, Zn, and Pb indicate a hydrothermal origin of the ferro-manganese mineralization. The radiolarian taxa found indicate four age groups for the nodules that are embedded in the siliceous shale matrix that yielded a Middle Jurassic age (middle Bathonian). The first group includes a nodule of Late Triassic age (late Norian to Rhaetian); the second group nodules of Early Jurassic age (late early to late Pliensbachian and probably middle-late Toarcian); the third group nodules of early Middle Jurassic age (Aalenian-Bajocian); the last group finally includes nodules of late Middle Jurassic age (Bajocian-Bathonian). The presence of Upper Triassic to Middle Jurassic Mn-impregnated chert nodules in a Middle Jurassic matrix indicates a deep oceanic environment of deposition outside the Pelagonian realm (easternmost Adria Plate), which at that time was a shallow-water carbonate platform with a thin pelagic limestone cover. The chert nodules are with all certainty derived from the oceanic Maliac-Vardar domain and were, together with their host formation, tectonically emplaced onto the Pelagonian margin. We speculate that these nodules, more lithified than their matrix, were exhumed on the slope of an intra-oceanic accretionary wedge and were redeposited in the Middle Jurassic siliceous mudstones on the floor of the subducting Maliac-Vardar Ocean. [ABSTRACT FROM AUTHOR]

Rudolf Trümpy (1921-2009) was one of the great Alpine geologists of the twentieth century and an influential figure in the international geological community. He played a dominant role in the change of opinion concerning the Alpine evolution by showing that normal faulting dominated the early development of the Alpine realm from the Triassic to the early Cretaceous. This provided a convenient model for later plate-tectonic interpretations of collisional mountain belts. His further recognition of strike-slip faulting during all stages of the Alpine evolution presaged the realisation that the Alps were not built by a simple open-and-shut mechanism. Trümpy was educated during an intellectual lull, a time when simplistic models of the earth behaviour inherited from the middle of the nineteenth century became prevalent under the influence of a close-minded, positivist approach to geological problems. This period, which we term the Dark Intermezzo, lasted from about 1925 to 1965. The grand syntheses of Suess and Argand which preceded this period were viewed from this narrow angle and consequently misunderstood. It was thought that earth history was punctuated by global orogenic events of short duration taking place within and among continents and oceans whose relative positions had remained fixed since the origin of the planet. These views, summarised under the term 'fixism', were developed when the ocean floors were almost totally unknown. When data began coming in from the post World War II oceanographic surveys, the world geological community was slow to receive and digest them. Trümpy followed these developments closely, realising that his work was important in placing the geology of the mountain belts within the emerging, new theoretical framework. He adopted the position of a critic and emphasised where detailed knowledge of the Alps, unquestionably the best known mountain belt in the world, supported and where it contradicted the new ideas. His voice was listened to carefully and subsequent developments have shown his critique to have been prescient. It is regrettable that he did not publish some of the theoretical criticisms he communicated to his colleagues during scientific meetings and informal conversations. His hesitance in becoming involved in theoretical arguments in geology may have stemmed partly from his scientific upbringing during the Dark Intermezzo and partly because he genuinely believed that he was better off sticking to what he thought he knew for sure. He nevertheless stressed that it is important for geologists 'to dream'. It is often said about teachers that one should do what they say, not what they do. In Trümpy's case, it was the opposite. Both scientifically and as a human being, he was a most admirable man. [ABSTRACT FROM AUTHOR]

In the Kraishte region, near the junction of the Balkanides and Dinarides, late Early Cretaceous compression led to the thrusting of the Morava unit over the Struma unit. Structural investigations, combined with zircon fission track and 40Ar/39Ar analyses, have been used to reconstruct the geological history of the area and to clarify the original tectonic position of the main units before Cenozoic extension. The results show that Early Cretaceous lower amphibolite facies metamorphism and deformation in the Osogovo-Lisets Metamorphic Complex were related to top-to-the-NE directed nappe stacking, whereas the deeper parts of the allochthonous Morava unit experienced low-grade metamorphic overprint at temperatures >∼260°C. The structurally intermediate Struma Diorites and their Mesozoic cover experienced temperatures between ∼170°C and 300°C. Thrusting of the Morava onto the Struma unit started probably in Valanginian times (140-136 Ma), soon after the cessation of preorogenic to synorogenic turbidite sedimentation on Struma. The metamorphic peak was reached before 112 Ma. Subsequent extension-related cooling of both units was probably accompanied by the formation of low-angle normal faults. [ABSTRACT FROM AUTHOR]

An obituary for Hans P. Laubscher, Professor emeritus of Geology at the University of Basel, is presented.

In contrast to Northern Europe where, in the 19th Century, a coherent lithostratigraphy and biostratigraphy was established, many of the ‘odd rocks of mountain belts’ (as christened by Alfred G. Fischer) of the Alpine-Mediterranean region defied an easy interpretation in terms of the simple English layer-cake stratigraphy mapped by William Smith. However, as early as 1862, Eduard Suess recognized close affinities between Mesozoic faunas of the Alps and those of the Himalaya. Suess also described many such Alpine sedimentary rocks as pelagic (a term discussed by Antoine Lavoisier in the context of sea-level change), and the results of the Challenger Expedition (1872 to 1876) convinced the Viennese school of geologists of their deep-water nature. Based on the composition of Jurassic–Cretaceous faunas, Melchior Neumayr postulated the existence of an equatorial ocean, the ‘Central Mediterranean’ which extended from Central America through the Alpine belt to the Himalaya and beyond, an ocean which Suess subsequently named ‘Tethys’. The question of whether or not deep-sea sediments could occur on land, as deliberately posed by Gustav Steinmann in 1925, became central to the long-lasting controversy on the permanency of continents and ocean basins. Indeed, the occurrence of deep-sea deposits in mountain belts required the disappearance of oceanic areas and a mobilist concept of orogeny that was subsequently applied to the Tethyan region by Emile Argand in the wake of the continental drift hypothesis of Alfred Wegener. Implicit in the views of Wegener and Argand is the concept of an oceanic crust fundamentally different from that of the continents. Although ophiolites had been recognized as a special group of rocks in the early 19th Century, Steinmann was the first to interpret the association of (serpentinized) peridotite, ‘diabase’ (dolerite–basalt) and radiolarite (Steinmann Trinity) in a geodynamic context and to consider it as characteristic of the deep ocean. The comparison of Alpine radiolarites with Recent radiolarian oozes deposited below the calcite compensation depth did not remain unchallenged, because of the local association of these siliceous rocks with coarse clastic deposits. However, after the advent of the turbidity-current hypothesis, these detrital deposits were reinterpreted as submarine mass-flow deposits. Consequently, such typical Tethyan facies as Rosso Ammonitico, Maiolica/Biancone and black shales, found in close stratigraphical association with the radiolarites, could be interpreted as deposited on deeply submerged continental and/or oceanic crust where they recorded faithfully a range of interdependent palaeoceanographic phenomena: changes in the relative proportion of siliceous, carbonate and organic-walled biota, in carbonate saturation of sea water, in oceanic circulation and in the impact of orbital-climatic cycles. The results of the Deep Sea Drilling Project, with its discovery of typical Jurassic and Cretaceous Tethyan facies in the Atlantic Ocean, dramatically confirmed the early interpretations of European geologists of the 19th and early 20th Centuries. [ABSTRACT FROM AUTHOR]

The concept of turbidite has evolved so much since its original definition by Kuenen and Migliorini in 1950 – i.e. the deposit of turbidity currents exemplified by the sandy flysch successions of the Northern Apennines – that it is now used to define a variety of deposits, some of which have little in common with sandy flysch formations in terms of facies, geometry and geological significance. The extension of the concept to other geodynamic settings and deposits of non-siliciclastic composition is considered only briefly in the concluding sections. With the diffusion of the concept of turbidity current, in the 1950s and early 1960s, an entirely new branch of sedimentology came into being, concerned with the inventory of sedimentary structures, palaeocurrent measurements and bedding patterns. The most representative expression of this branch came from the ‘Dutch school’ of Philip H. Kuenen and his students. Between the late 1960s and the mid-1970s, there was a new development: facies analysis, in terms of modern environments and depositional systems. This development led to the introduction and discussion of ‘fan models’ that became an increasingly thorny issue with the accumulation of data from modern deep-marine settings. In particular, most researchers emphasized the importance of channel and lobe elements and their mutual relationships in space and time... [ABSTRACT FROM AUTHOR]

We challenge the former interpretation of the ‘sedimentary mélange’ of the Makran accretionary complex as a tectonic mélange diapirically emplaced from below and provide evidence for its sedimentary gravitational emplacement from the north during Tortonian–Messinian times (between 11.8 and 5.8 Ma). It is an olistostrome that includes blocks of ophiolites and oceanic sediments derived from the ‘coloured mélange’ to the north, and reworked chunks of the turbidites on which it rests with an erosional truncation. The chaotic scattering of blocks of any size and lithology and the weak, soft-sediment deformation of the matrix argue against a tectonic emplacement of the chaotic formation. Its size and internal structure, together with the size of the individual blocks, make the olistostrome a fossil equivalent of the large, gravitationally emplaced debris flows observed along present-day continental margins and unstable volcanic edifices. [ABSTRACT FROM AUTHOR]

A correlation of tectonic units of the Alpine-Carpathian-Dinaridic system of orogens, including the substrate of the Pannonian and Transylvanian basins, is presented in the form of a map. Combined with a series of crustal-scale cross sections this correlation of tectonic units yields a clearer picture of the three-dimensional architecture of this system of orogens that owes its considerable complexity to multiple overprinting of earlier by younger deformations. The synthesis advanced here indicates that none of the branches of the Alpine Tethys and Neotethys extended eastward into the Dobrogea Orogen. Instead, the main branch of the Alpine Tethys linked up with the Meliata-Maliac-Vardar branch of the Neotethys into the area of the present-day Inner Dinarides. More easterly and subsidiary branches of the Alpine Tethys separated Tisza completely, and Dacia partially, from the European continent. Remnants of the Triassic parts of Neotethys (Meliata-Maliac) are preserved only as ophiolitic mélanges present below obducted Jurassic Neotethyan (Vardar) ophiolites. The opening of the Alpine Tethys was largely contemporaneous with the Latest Jurassic to Early Cretaceous obduction of parts of the Jurassic Vardar ophiolites. Closure of the Meliata-Maliac Ocean in the Alps and West Carpathians led to Cretaceous-age orogeny associated with an eclogitic overprint of the adjacent continental margin. The Triassic Meliata-Maliac and Jurassic Western and Eastern Vardar ophiolites were derived from one single branch of Neotethys: the Meliata-Maliac-Vardar Ocean. Complex geometries resulting from out-of-sequence thrusting during Cretaceous and Cenozoic orogenic phases underlay a variety of multi-ocean hypotheses, that were advanced in the literature and that we regard as incompatible with the field evidence. The present-day configuration of tectonic units suggests that a former connection between ophiolitic units in West Carpathians and Dinarides was disrupted by substantial Miocene-age dislocations along the Mid-Hungarian Fault Zone, hiding a former lateral change in subduction polarity between West Carpathians and Dinarides. The SW-facing Dinaridic Orogen, mainly structured in Cretaceous and Palaeogene times, was juxtaposed with the Tisza and Dacia Mega-Units along a NW-dipping suture (Sava Zone) in latest Cretaceous to Palaeogene times. The Dacia Mega-Unit (East and South Carpathian Orogen, including the Carpatho-Balkan Orogen and the Biharia nappe system of the Apuseni Mountains), was essentially consolidated by E-facing nappe stacking during an Early Cretaceous orogeny, while the adjacent Tisza Mega-Unit formed by NW-directed thrusting (in present-day coordinates) in Late Cretaceous times. The polyphase and multi-directional Cretaceous to Neogene deformation history of the Dinarides was preceded by the obduction of Vardar ophiolites onto to the Adriatic margin (Western Vardar Ophiolitic Unit) and parts of the European margin (Eastern Vardar Ophiolitic Unit) during Late Jurassic to Early Cretaceous times. [ABSTRACT FROM AUTHOR]

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Albert W. Bally, Professor emeritus of Geology at Rice University in Houston, passed away on the 30th of July in Houston. In Switzerland, Bally obtained his baccalaureate and began to study Geology at Zurich University. As Bally noted in his curriculum vitae, 'August 1981 marked my return as geologist to Italy, almost 30 years after publication of my Ph.D. thesis in 1954'. [Extracted from the article]

The Broccatello lithological unit (Lower Jurassic, Hettangian to lower parts of Upper Sinemurian) near the village of Arzo (southern Alps, southern Switzerland) is a mound-shaped carbonate deposit that contains patches of red stromatactis limestone. Within the largely bioclastic Broccatello unit, the stromatactis limestone is distinguished by its early-diagenetic cavity system, a relatively fine-grained texture, and an in-situ assemblage of calcified siliceous sponges (various demosponges and hexactinellids). A complex shallow subsurface diagenetic pathway can be reconstructed from sediment petrography in combination with comparative geochemical analysis (carbon and oxygen isotopes; trace and rare earth elements, REE + Y). This pathway includes organic matter transformation, aragonite and skeletal opal dissolution, patchy calcification and lithification, sediment shrinkage, sagging and collapse, partial REE remobilization, and multiple sediment infiltration. These processes occurred under normal-marine, essentially oxic conditions and were independent from local, recurring syn-sedimentary faulting. It is concluded that the stromatactis results from a combination of calcite mineral authigenesis and syneresis-type deformation. The natural stromatactis phenomenon may thus be best explained by maturation processes of particulate polymer gels expected to form in fine-grained carbonate sediments in the shallow subsurface. Conditions favorable for the evolution of stromatactis appear to be particularly frequent during drowning of tropical or subtropical carbonate platforms. [ABSTRACT FROM AUTHOR]

At Montagna della Maiella and at Gola del Furlo (central Apennines) two discrete layers of bentonic clay are intercalated within the pelagic (Furlo) and turbiditic/pelagic limestones (Maiella) of the Upper Cretaceous basinal succession of the Umbrian basin (Scaglia facies). The bentonite layers are dated by planktonic foraminifera to the Globotruncanita elevata zone, early Campanian, and by calcareous nannofossils to the Aspidolithus parcus zone (CC 18); they fall into the reversed interval of chron 33. Detailed correlation shows the layers to be of exactly the same age. The upper layer is dated by U/Pb on magmatic zircons to 81.67±0.21 Ma, an age compatible with the Cretaceous time-scale of Obradovich. The mineralogy of the bentonitic clays is almost pure montmorillonite and contrasts sharply with the clay mineral assemblage of the enclosing pelagic and turbiditic limestones, which is dominated by soil-derived smectite and illite in different proportions. The bentonite seams are interpreted as the submarine alteration products of wind-borne volcanic ashes. They can be followed with only minor changes in thickness over 200 km and must be derived from distant volcanic sources and related to extreme volcanic events. A possible source area is present in the Dinarides where Upper Cretaceous subduction-related magmatic rocks are widespread. [ABSTRACT FROM AUTHOR]

Top-basement detachment faults (TBDF) represent exhumed segments of downward-concave detachments accommodating tens of kilometers of offset. TBDFs are key structures of magma-poor rifted margins, but are difficult to identify in seismic profiles, because they coincide with top-basement reflections. We have constructed realistic seismic models of an Alpine example, which were used to simulate full marine seismic surveys and to identify the seismic fingerprint of TBDFs in CMP-stacked and time-migrated sections. Minor extensional allochthons, which locally cap TBDFs, give rise to pronounced diffractions, which are in stark contrast to continuous reflections from uncapped segments of TBDFs. In time-migrated synthetic sections we find a continuous and constant amplitude reflection alternating with a laterally discontinuous reflection of variable amplitude. These diagnostics were also identified in the Lusigal 12 seismic profile imaging the Hobby High detachment, a TBDF in the Iberia Abyssal Plain. Using these diagnostics, small extensional allochthons and high-angle faults cutting the Hobby High detachment are observed in Lusigal 12 and the entire sedimentary cover can be shown to be postrift. [ABSTRACT FROM AUTHOR]

The tectonic interpretation of basement structures in seismic reflection profiles from ocean-continent transitions (OCT) of magma-poor rifted margins is notoriously difficult due to the scarcity of borehole information. Low-angle intra-basement reflections are frequently interpreted as detachment faults, and in certain locations the drilled top of the basement is interpreted as exhumed detachment fault. The seismic expression of such detachment faults is, however, poorly understood. We address this problem by comparing synthetic seismic data from the Tasna OCT, an exposed remnant of a Tethyan margin, with seismic reflection data from Hobby High, a drilled basement high within the west Iberian margin. Both sites are widely considered as being representative of OCT zones. Their geological similarity and the complementary nature of the data enable us to perform a detailed investigation of the seismic structure and response of these OCT zones. This provides insights into the seismic imaging of OCT zones in general and the tectonic evolution of the associated detachment systems in particular. On the basis of the Tasna OCT models and their seismic responses we have identified some potential characteristics of intra- and top-basement detachments: (i) variable amplitudes and numerous diffractions from the top of exhumed subcontinental mantle, (ii) a continuous and strong reflection imaging the top of exhumed lower crustal rocks, and (iii) a weak and discontinuous reflection of inverse polarity representing a shallow intra-basement crust-mantle detachment. Similar features are consistently observed at geologically equivalent positions in the seismic data from Hobby High and may thus serve as guidelines for interpretation of seismic data from un-drilled OCT zones. [ABSTRACT FROM AUTHOR]

We provide new geological and isotope geochemical constraints on the evolution from continental rifting to sea-floor spreading along a segment of the Jurassic Tethyan margin exposed in the Platta and Err nappes (eastern Central Alps). Field observations show that the ocean–continent transition zone is characterized by oceanward-dipping detachment faults leading to the exhumation of subcontinental mantle rocks subsequently intruded by gabbro bodies and dolerite dikes, and covered by pillow basalts and radiolarites. Zircons extracted from gabbros and albitite yield concordant U–Pb ages of 161 ± 1 Ma; their initial ℇHf (+ 14.4 to + 14.9) as well as bulk rock ℇNd values of from gabbros and basalts (+ 7.3 to + 9.5) point to a MORB-type depleted mantle source. These data suggest that the onset of magmatic activity coincides with the latest phase of mantle exhumation along low-angle detachment faults and may be controlled by upwelling asthenosphere beneath a zone of exhumed continental mantle. [ABSTRACT FROM AUTHOR]

Presents a study which compared the history of the Cretaceous margin of Galicia with that of the Jurassic margin of the Alpine Tethys involved in Alpine thrusting and nappe formation. Anatomy of the margins; Discussion; Conclusions.

Although of different age, the undeformed Cretaceous Iberia/Newfoundland margins and the relics of the Jurassic Briançonnais/Adriatic margins preserved in the Alps document a similar spatial and temporal evolution of rifting suggesting that the evolution of both pairs of margins was controlled by the same processes. Rifting appears to depend strongly on the thermal history of the lithosphere, which controls the rheology and consequently also the structural evolution of the margin. The tectonic evolution of non-volcanic margins appears to be distinctly different from that of volcanic ones. [ABSTRACT FROM AUTHOR]

The article announces that A. M. Celâl Şeng ör has received the Gustav-Steinmann-Medal 2010.

The article presents the author's comments on the contribution of the association Geologische Vereinigung to the development of the field of geology and earth sciences. He says that the organization is celebrating its 100th anniversary in 2010. Its first meeting was held in 1910 at the Senckenberg Museum in Frankfurt, Germany. The author also talks about the periodical "Geologische Rundschau," published by the association.

The article presents a response by the author to Ganapathy Shanmugam comments on the article "Turbidities and turbidity currents from Alpine flysch to the exploration of continental margin". He apologizes for not being clear about the turbidite origin of the coarse-grained division in his paper. He states that Shanmugam did not give much importance to J. E. Sanders while introducing the problem of high-density turbidity currents and sandy debris flows.

The article discusses several issues including the International Geological Congress held in Florence, Italy, the introductory chapter in the 2009 issue and people who made their contributions. The theme of the congress held from 20-28 August 2008 was 'From the Mediterrranean toward a Global Renaissance'. The introductory chapter focuses on chapters which document significance of Mediterranean geology. Several people have been thanked for their contributions including Darrel Cowan and Chim Kopf.