Mass Transport Complexes in structurally-controlled basins: the Epiligurian Specchio Unit (Northern Apennines, Italy)

Il recente incremento dell’esplorazione geofisica dei margini continentali e il concomitante sviluppo di tecnologie d’indagine, sismiche ed acustiche, sempre più accurate, hanno rivelato la comune presenza di vasti accumuli di sedimenti rimobilizzati a causa di franamenti sottomarini, e comunemente identificati con il termine di Mass Transport Deposit o Complex (MTD e MTC, rispettivamente). Attualmente, queste unità sono intensamente studiate non solo per ragioni strettamente scientifiche, quali il loro significato ambientale, la comprensione dei processi di innesco e il loro ruolo nell’evoluzione dei flussi densi di sedimento, ma anche per ragioni socio-economiche, principalmente nella mitigazione del rischio geologico e nell’esplorazione petrolifera. D’altra parte, gli studi di affioramento su esempi fossili di MTDs sono relativamente scarsi se rapportati all’enorme quantità di dati provenienti dalla geologia marina. Una serie di problemi emerge dai tentativi di comparazione reciproca tra i dati provenienti da questi due tipi di approccio, principalmente a causa dei limiti di risoluzione ed dei problemi di scala insiti nei due metodi, e a causa della relativa scarsità di contesti geodinamici confrontabili, e spesso caratterizzati da interpretazioni discordanti (i.e. contesti di margine convergente/collisionale versus contesti di margine divergente). Questi ultimi punti sono particolarmente evidenti per i prismi di accrezione, dove diversi fattori di controllo convergono nella formazione di “unità caotiche” a differenti scale. Questa situazione mette in luce la necessità di una comparazione sistematica ed un approccio integrato nello studio di questo tipo di unità per una migliore comprensione del loro significato geologico, specialmente per quei bacini che si trovano al di sopra dei prismi di accrezione e che rappresentano il contesto di studio ideale per la comprensione del ruolo che ricoprono i MTDs nell’evoluzione dell’intero sistema collisonale, a dispetto del loro relativamente limitato riconoscimento all’interno del registro geologico, sia recente che fossile. Tenendo conto di queste problematiche e con lo scopo di contribuire in parte a colmare tali lacune, viene qui affrontato lo studio di affioramento di un esempio fossile di MTC, conosciuto come Unità Specchio tra i geologi dell’Appennino, e classicamente ritenuto essersi sviluppato al tetto di un prisma di accezione in formazione. Questa unità è compresa nella parte basale (Rupeliano inferiore) dei depositi sin-orogenici delle Unità Epiliguri eocenico-oligoceniche, affioranti sul margine orientale dell’Appennino Settentrionale, sotto forma di resti isolati di successioni stratigrafiche (i.e. placche epiliguri), e che rappresenterebbero i riempimenti di bacini confinati di scarpata sviluppatisi al tetto della Falda Ligure durante la sua traslazione tettonica (i.e. prisma di accrezione proto-appenninico). Questo studio si compone di analisi stratigrafiche e strutturali, dalla scala cartografica a quella microscopica, svolte direttamente sui corpi da frana, e sulle successioni sedimentarie sovra- e sottostanti, e successivamente integrate da un tentativo di comparazione sistematica con i possibili analoghi moderni finora riconosciuti, focalizzando l’attenzione sugli aspetti legati sia al corpo di frana che alla fisiografia del contesto deposizionale originale. Il primo importante risultato ottenuto attraverso questi dettagliati studi d’affioramento, riguarda la suddivisione dell’Unità Specchio in cinque (5) sotto-unità che rappresentano almeno quattro (4) distinti MTDs: quelli stratigraficamente più bassi, di significato locale, mostrano provenienze dai settori meridionali, mentre quelli sovrastanti, di significato bacinale, mostrano provenienze dai settori settentrionali. Tra questi, il corpo di maggiori dimensioni raggiunge un volume stimabile a circa 150 km3. L’impilamento verticale di questi MTDs e la natura progressivamente sempre più marino-marginale dei suoi componenti, suggeriscono una deposizione da parte di eventi strettamente ravvicinati nel tempo, originatisi in seguito a processi di collasso retrogradazionale a spese di aree sempre più prossimali dell’originario bacino. Le accurate osservazioni sugli elementi interni di queste unità (i.e. matrice e blocchi) hanno permesso di sviluppare ipotesi riguardanti i possibili meccanismi evolutivi interni ai corpi di frana: in primo luogo attraverso la dettagliata descrizione di corpi sedimentari generati da processi catastrofici, che includono sia facies da slump che da debris flow (i.e. depositi da blocky flow di Mutti et al., 2006), e, secondariamente, con la caratterizzazione di quelle evidenze collegate all’influenza esercitata dal confinamento strutturale sulla messa in posto dei suddetti corpi, principalmente in termini di ridirezionamento forzato della massa franata, sovra-ispessimenti localizzati, “accoppiamento” con il substrato (erosione del fondo in senso sedimentologico), e distribuzione interna degli sforzi indotta da costrizioni morfologiche. In particolare, questo studio mette in luce la possibile presenza di un buckling laterale generalizzato (compressione + transpressione), in senso trasversale alla principale direzione di movimento, e di un taglio generalmente unidirezionale in senso longitudinale allo stesso, con importanti ripercussioni sullo studio della cinematica di questi processi. Questo studio contribuisce inoltre alla comprensione delle configurazioni dei bacini di scarpata ospitanti l’Unità Specchio, evidenziando le differenze che intercorrono tra le associazioni di facies nelle successioni sedimentarie sotto- e sovrastanti l’Unità Specchio, e suggerendo la possibile esistenza di un regime di tettonica “pellicolare” a carico delle coperture sedimentarie epiliguri (tettonica gravitativa al tetto del prisma?). Questo tipo di regime tettonico (“slope-tectonics”-type ?) prevede lo sviluppo sinergico di diapirismo fangoso ricollegabile a fenomeni di thrusting e trascorrenza, e la formazione di MTDs localizzati a piccola scala, a carico dei margini di bacino e degli alti strutturali intrabacinali; questi elementi, combinati, vanno a contribuire alla formazione di una fisiografia generalmente accidentata del profilo di scarpata, con l’enucleazione di depocentri isolati, separati da alti strutturali (i.e. above-grade slope). Infine, vengono qui tentativamente affrontate alcune considerazioni sul contesto paleogeografico generale delle successione epiligure al tempo del Rupeliano inferiore, attraverso l’integrazione delle ipotesi finora classicamente accettate in letteratura con i risultati del presente studio, principalmente in termini di direzioni di trasporto dei MTDs, della loro provenienza e del significato ambientale dei materiali coinvolti. Le evidenze di un documentato vulcanismo calkalcalino attivo, caratterizzato da centri eruttivi distanti (in particolare viene qui riportata la prima segnalazione di strati vulcanoclastici risedimentati all’interno della successione sedimentaria sovrastante l’Unità Specchio nella placca della Val Pessola), assieme alle evidenze di controllo tettonico e climatico mostrate dai depositi che segnano la ripresa della sedimentazione al di sopra del MTC, potrebbero contribuire a vincolare i possibili meccanismi di innesco e i fattori precondizionanti responsabili dello sviluppo dei MTDs costituenti, fornendo inoltre informazioni indirette sulle configurazioni generali delle aree-fonte. Queste osservazioni dimostrano come ulteriori studi specifici condotti su “unità caotiche” precedentemente sottovalutate possano contribuire in modo significativo ad una migliore comprensione del sistema orogenico appenninico, e allo stesso tempo, introdurre nuove sfide nell’applicazione dei risultati su altre catene orogeniche nel resto del mondo. Alcune delle conclusioni qui presentate sono in contrasto con l’attuale linea di pensiero secondo la quale i margini convergenti sismicamente attivi sarebbero caratterizzati dalla presenza di MTDs di dimensioni relativamente piccole, ed in minor numero rispetto a quanto ipotizzato per i margini continentali divergenti. In queste situazioni, le frane sottomarine si originerebbero preferibilmente nelle vicinanze del fronte di deformazione principale, solitamente localizzato in acque relativamente profonde. Tralasciando alcuni margini convergenti specifici (e.g. settore meridionale della fascia convergente di Cascadia, settore nord-orientale della Nuova Zelanda, Arco Aleutino occidentale), e particolarmente quelli caratterizzati da collisione continentale (e.g. settore nord-occidentale del Borneo), dove sono segnalati alcuni esempi di MTDs a grande scala e sviluppo catastrofico, nelle tipiche situazioni di margine convergente (in particolare quelle caratterizzate da consunzione di crosta oceanica; e.g. Perù, Costa Rica), le frane sottomarine con dimensioni comparabili a quelle dei margini divergenti sono invece caratterizzate da una cinematica relativamente lenta, e comunemente attribuite a fenomeni legati alle dinamiche di subduzione (e.g. collisione di un seamount). Ciononostante, questo lavoro sembra confermare lo sviluppo di MTDs a grande scala e di carattere catastrofico nei dominii deposizionali più interni di un prisma d’accrezione (i.e. in posizione interna rispetto al fronte di deformazione principale, nel senso di vergenza orogenica della catena), originandosi da collassi in ambiente marino-marginale (i.e. acque relativamente basse), anche con il possibile coinvolgimento di aree prossime alla linea di costa, con importanti implicazioni, soprattutto dal punto di vista del rischio geologico (e.g. alto potenziale tsunamigenico). In conclusione è possibile perciò affermare che un approccio di campagna di tipo integrato allo studio dei MTDs contribuirebbe in modo determinante alla risoluzione dei problemi di scala inerenti lo studio dei depositi da frana sottomarina. In particolare, questo tipo di approccio apporterebbe un significativo ausilio alla corretta interpretazione delle “unità caotiche”, sedimentarie e tettoniche, affioranti nelle catene orogeniche, così come quelle che caratterizzano le moderne fasce convergenti sottomarine.The recent increasing in geophysical exploration of continental margins and the concomitant progress of increasingly more sophisticated seismic- and acoustic-imagery technologies have shown the widespread occurrence of large accumulations of remolded sediments generated by submarine landslides, and commonly referred to as Mass Transport Deposits or Complexes (MTD and MTC, respectively). These units are being intensively investigated, not only for strictly scientific reasons, such as their environmental significance, understanding of triggering processes, and their role in the transformation of density flows, but also because of economic and social implications, mainly in terms of hydrocarbon exploration and production, and geohazards. On the other hand, field-based studies on ancient examples of MTDs are relatively scarce with respect to the huge amount of data derived from marine geology. Many problems arise from the tentative comparison of the data derived from these two different approaches, mainly because of the resolution limits and scaling problems between these methods, and for the limited occurrences of comparable geodynamic contexts and relative unambiguous interpretations (i.e. collisional/convergent versus divergent margin settings). This is particularly evident for accretionary systems, where several controlling factors combine to produce “chaotic units” at different scales. This kind of situation highlights the need of a systematic comparison and an integrated approach to the study of such units for a better understanding of their geologic significance, especially for those depositional environments located on top of accretionary prisms, which represent an ideal setting for studying the role of mass transport deposits in the wedge evolution, in spite of their yet relatively poor recognition in the modern and ancient rock record. Keeping in mind the above problems and in order to partly fill this gap, this study has been carried out through a field-based work carried on an ancient example of MTC, known as the Specchio Unit among the Apennine geologists, and typically developed on top of an accretionary prism. This unit occurs within the lower Rupelian rocks of the syn-orogenic sedimentary record of the Eocene-Oligocene Epiligurian succession, cropping out in the eastern side of the Northern Apennines (Italy) as isolated sedimentary remnants (i.e. outliers), representing the fill of local intra-slope basins developed on top of the translating Ligurian Nappe (i.e. proto-Apenninic accretionary wedge). This study has been developed through cartographic- to microscopic-scale stratigraphic and structural analyses, collected directly on the slide bodies and on the over- and under-lying sedimentary succession, along with an attempt of systematic comparison with so far recognized modern analogs, focusing on both the slide-related features and the overall physiography of the original depositional setting. The first important result coming out from these detailed outcrop studies, is the subdivision of this MTC into five sub-units, representing at least four distinct MTDs: the lower ones, of local significance, derived from the southern sectors, and the upper ones, of basin-wide extent, derived from the northern sectors. The largest MTD reaches an inferred volume of involved material of about 150 km3. The vertical stacking of these MTDs and the progressively “shallower water nature” of the internal components, seems to represent the deposition from closely spaced events, originated through a retrogressive failure process, involving progressively more proximal areas. Careful observations carried on the internal elements of these units (i.e. matrix and blocks) allow considerations on slide mechanics, with the detailed characterization of sedimentary bodies generated by catastrophic processes, which include both slump- and debris flow-like facies (i.e. blocky-flow deposits of Mutti et al., 2006), and the influence exerted by structural confinement on the slide emplacement, mainly in term of forced slide direction, localized over-thickening, substrate coupling (bed erosion in a sedimentological sense) and margin-induced strain partitioning. In particular, this study highlights the likely occurrence of a generalized lateral buckling (compression + transpression), transversally to the main sliding direction, and an overall unidirectional shearing in the longitudinal sense, giving important information on the slide kinematics. This study also contributes to the understanding of the local intra-slope basin configuration, highlighting the differences in facies associations between pre- and post-slide emplacement sedimentary successions, and the possible existence of an overall shallow level tectonism (gravity-related?). This kind of “slope-tectonics”-type regime forecasts the synergic development of thrust- and strike slip-related shale diapirism and local, small-scale MTDs, affecting basin margins and intrabasinal highs, and contributing to the development of an overall above-grade slope physiography. Moreover, some regional considerations on the palaeogeograhic setting of the lower Rupelian Epiligurian succession can be made, integrating the so far accepted hypothesis from the literature with the results of this study, mainly in terms of transport directions, provenance and environmental significance of the involved material. The evidence of a far-located calcalkaline volcanism (in particular here I report the first recognition of resedimented volcaniclastic beds in the sedimentary succession on top of the Specchio unit, in the Pessola Valley outlier), along with the climatic- and tectonic-related signatures characterizing the restored sedimentation, could contribute in constraining the possible triggering mechanisms and preconditioning factors of slide development, thus giving indirect information on the general configurations of source areas. These observations demonstrate that further specific studies on previously overlooked “chaotic” units may significantly contribute to a better understanding of the Apenninic orogenic system, and, at the same time, introducing new challenges for their application into other orogenic belts worldwide. Part of these conclusions are in contrast with the nowadays-generalized belief that seismically active convergent margins are characterized by the occurrence of relatively few and smaller scale MTDs, if compared to divergent margin settings. In such contexts, submarine landslides are thought to develop close to the main deformation front, commonly located in deep-water settings. Apart from some specific convergent margins (e.g. southern Cascadia, NE New Zealand, western Aleutinian Arc), particularly those involving a continental collision (e.g. NW Borneo), where some catastrophic, large-scale MTDs are observed to occur, in typical convergent margin settings (particularly those involving oceanic crust consumption; e.g. offshore Perù, Costa Rica), MTDs sharing huge dimensions with those of divergent margins are instead characterized by overall slow-rate motion, and are thought to be commonly linked to subduction dynamics (e.g. colliding seamount). In spite of these interpretations, this work seems to confirm the possible occurrence of catastrophic, large-scale MTDs on the internal depositional domains of an accretionary prism (i.e. internally from the main tectonic front), which may originate from shallow-water regions, also possibly involving near-shore areas, with consequent important implications, for example, in terms of geohazard purposes. In summary, it is possible to suggest that an integrated field-based approach to the study of MTDs may significantly contribute to solve some scaling problems about submarine landslide deposits. In particular, this approach should be useful in facing the difficulties regarding the interpretation of “chaotic” units cropping out in orogenic belts, as well as those characterizing modern submarine collisional belts

TECHNICAL FACTORS REQUIRED FOR PROPER BODY TRANSLATION IN THE DISCUS THROW

The purpose of this study was to gain knowledge about technical requirement in male discus throwers, specific to their performance level, by comparing the parameters of body translation. The performances of 22 male discus throwers were analyzed. The subjects were divided into the following three groups based on the distance thrown: advanced, medium, and novice. From the results of this study, it can be concluded that the relevant technical requirement for novice is a dynamic shifting of the center of gravity to the left during the first double support phase. Furthermore, pushing into the ground vigorously before push-off the left foot to drive the body toward the throwing direction during the flight phase would enable novice group to create greater momentum and achieve a higher performance level

Origin and significance of olistostromes in the evolution of orogenic belts: A global synthesis

Olistostromes (sedimentary m\ue9langes) represent the products of ancient submarine mass transport processes. We present a comparative analysis of the occurrences and internal structures of these sedimentary m\ue9langes at a global scale with a focus on the Circum-Mediterranean, Appalachian and Circum-Pacific regions, and discuss their formation and time-progressive evolution in different tectonic settings. Lithological compositions, stratigraphy, and structural features of olistostromes reflect the operation of an entire spectrum of mass transport processes during their development through multi-stage deformation phases. The general physiography and tectonic setting of their depocenters, the nature, scale and rate of downslope transformation mechanisms, and global climatic events are the main factors controlling the internal structure and stratigraphy of olistostromes. Based on the tectonic settings of their formation olistostromes are classified as: (i) passive margin, (ii) convergent margin and subduction\u2013accretion, and (iii) collisional and intra-collisional types. Systematic repetitions of these different olistostrome types in different orogenic belts provide excellent markers for the timing of various tectonic events during the Wilson cycle evolution of ocean basins. Olistostromes are best preserved in paleo active margins, covering vast areas of thousands of km2, where they underwent significant downslope translation, up to hundreds of kilometers. Incorporation of olistostromes into subduction\u2013accretion complexes and orogenic belts takes place during discrete episodes of tectonic events, and their primary (sedimentary) fabric may be commonly reworked and overprinted by subsequent phases of tectonic and metamorphic events. We apply the basic nomenclature of structural geology, sedimentology and basin analysis in studying the internal structure, lithological makeup, and mechanisms of formation and extraordinary downslope mobility of olistostromes

COMPARISON OF WORLD ELITE AND JAPANESE ELITE THROWERS IN THE DISCUS THROW

The aim of this study is to clarify the differences between world elite and Japanese elite throwers in the discus throw by comparing their hip-shoulder and shoulder-arm separation angles. The performances of 12 male world elite discus throwers (the World group) and 12 male Japanese elite discus throwers (the National group) were analysed. The hip-shoulder and shoulder-arm separation through the throwing motion were greater in the World group than in the National group. In the World group, the hip-shoulder separation reached its local maximum at the middle of 2nd single support phase, and the shoulder-arm separation reached its local maximum around left-foot touchdown to the ground; whereas in the National group, the former reached its local maximum in the first half of 2nd single support phase, and the latter reached its local maximum in the middle of the delivery phase. Although the shoulder led hip in both the World and National groups, the shoulder led the arm in the National group and the arm led the shoulder in the World group at release. These results showed that the World group released the discus in front of the shoulder while utilising the kinematic-chain appropriately, while the National group released the discus with the arm still trailing behind the shoulder

Experimental Study of a Novel Method of Cardiopulmonary Resuscitation Using a Combination of Percutaneous Cardiopulmonary Support and Liposome-encapsulated Hemoglobin (TRM645)

Percutaneous cardiopulmonary support (PCPS) has been applied for cardiopulmonary arrest (CPA). We have developed a novel method of cardiopulmonary resuscitation using PCPS combined with liposome-encapsulated hemoglobin (TRM645) to improve oxygen delivery to vital organs. Ventricular fibrillation was electrically induced to an adult goat for 10 min. Next, PCPS (30 ml/kg/min, V/Q: 1) was performed for 20 min. Then, external defibrillation was attempted and observed for 120 min. The TRM group (n5) was filled with 300 mL of TRM645 for the PCPS circuit. The control group (n5) was filled with the same volume of saline. The delivery of oxygen (DO2) and oxygen consumption (VO2) decreased markedly by PCPS after CPA, compared to the preoperative values. DO2 was kept at a constant level during PCPS in both groups, but VO2 slowly decreased at 5, 10, and 15 min of PCPS in the control groups, demonstrating that systemic oxygen metabolism decreased with time. In contrast, the decreases in VO2 were small in the TRM group at 5, 10, and 15 min of PCPS, demonstrating that TRM645 continuously maintained systemic oxygen consumption even at a low flow rate. AST and LDH in the TRM group were lower than the control. There were significant differences at 120 min after the restoration of spontaneous circulation (p&#60;0.05).</p

Architecture, deformation style and petrophysical properties of growth fault systems: the Late Triassic deltaic succession of southern Edgeøya (East Svalbard)

The Late Triassic outcrops on southern Edgeøya, East Svalbard, allow a multiscale study of syn‐sedimentary listric growth faults located in the prodelta region of a regional prograding system. At least three hierarchical orders of growth faults have been recognized, each showing different deformation mechanisms, styles and stratigraphic locations of the associated detachment interval. The faults, characterized by mutually influencing deformation envelopes over space‐time, generally show SW‐ to SE‐dipping directions, indicating a counter‐regional trend with respect to the inferred W‐NW directed progradation of the associated delta system. The down‐dip movement is accommodated by polyphase deformation, with the different fault architectural elements recording a time‐dependent transition from fluidal‐hydroplastic to ductile‐brittle deformation, which is also conceptually scale‐dependent, from the smaller‐ (3rd order) to the larger‐scale (1st order) end‐member faults respectively. A shift from distributed strain to strain localization towards the fault cores is observed at the meso to microscale (<1 mm), and in the variation in petrophysical parameters of the litho‐structural facies across and along the fault envelope, with bulk porosity, density, pore size and microcrack intensity varying accordingly to deformation and reworking intensity of inherited structural fabrics. The second‐ and third‐order listric fault nucleation points appear to be located above blind fault tip‐related monoclines involving cemented organic shales. Close to planar, through‐going, first‐order faults cut across this boundary, eventually connecting with other favourable lower‐hierarchy fault to create seismic‐scale fault zones similar to those imaged in the nearby offshore areas. The inferred large‐scale driving mechanisms for the first‐order faults are related to the combined effect of tectonic reactivation of deeper Palaeozoic structures in a far field stress regime due to the Uralide orogeny, and differential compaction associated with increased sand sedimentary input in a fine‐grained, water‐saturated, low‐accommodation, prodeltaic depositional environment. In synergy to this large‐scale picture, small‐scale causative factors favouring second‐ and third‐order faulting seem to be related to mechanical‐rheological instabilities related to localized shallow diagenesis and liquidization fronts.publishedVersio

円盤投における高い初速度獲得のための動作要因間の因果関係

The purpose of this study was to investigate, using path analysis, causal relationships among motion factors for achieving a high release velocity in the male discus throw. The throwing motions of 61 male discus throwers were analyzed using three-dimensional motion analysis. Variables such as release velocity, velocities gained by each body segment, body segment velocity, body angle and angular velocity were obtained. The path model indicating the causal relationships among these factors was constructed by path analysis.　The main results were as follows:　Influences of velocities gained by each body segment on release velocity were largest for the arm, followed in order by the trunk and legs.　Motion factors such as weight shift, acquisition of the velocity of the center of gravity, sweeping the legs, rotations of the hip and shoulder, twisting and untwisting of the trunk, acquisition of the velocity of the right knee and extension of the left knee had direct or indirect influences on the velocities gained by each body segment.　Motion factors in the path model revealed causal relationships along the time sequence of the throwing motion. In addition, the path model in this study indicated the cause and effect structure of the throwing motion by which Japanese male discus throwers were able to achieve a high release velocity. The results of this study can be utilized for technical coaching of the discus throw based on causal relationships