High-energy Events Research Articles

Ichnofabrics of the Capdevila Formation (early Eocene) in the Los Palacios Basin (western Cuba): Paleoenvironmental and paleoecological implications

The ichnofabrics present in the early Eocene siliciclastic deposits of the Capdevila Formation exposed in the Pinar del Rio area (Los Palacios Basin, western Cuba) are analyzed in this paper and their paleoecological and paleoenvironmental significance are discussed. Nine ichnofabrics were recognized in the dominantly sandy sedimentary succession: Ophiomorpha, Asterosoma, Thalassinoides, Palaeophycus, Scolicia, Bichordites-Thalassinoides, Rhizocorallium, Scolicia-Thalassinoides and rhizobioturbation. Diversity of ichnofauna is low and burrows made by detritus-feeding organisms in well oxygenated and stenohaline waters predominate. Suites of the Cruziana and Skolithos Ichnofacies lacking their archetypical characteristics were recognized, being impoverished in diversity and presenting dominance of echinoderm and decapods crustacean burrows as a response to the environmental stress caused by the high frequency of deposition. The ichnofabric distribution in the studied succession, its recurrence in the sandstone beds and the presence of a Glossifungites Ichnofacies suite with rhizobioturbation associated reflect a shoaling-upward event with subaerial exposure of the substrate. The integrated analysis of the ichnology and the sedimentary facies suggests deposition in a shallow slope frequently impacted by gravitational flows and high-energy events. The evidence of substrate exposure indicates the occurrence of a forced regression and suggests the existence of a sequence boundary at the top of the Capdevila Formation.

Coastal boulders as evidences of high-energy marine events from Diu Island, west coast of India: storm or palaeotsunami?

The coastal segment of Diu Island from west coast of India has been studied for its boulder deposits. The dimensions, morphology and characteristics of these boulders were studied to elucidate the type of wave responsible for their detachment from jointed shore platform and transport them to their present final position. The generated data were compared with wave height decay curves of strongest storm that has hit the Gujarat coastline (May 2001 storm). It was concluded that even the strongest storm ever recorded in Arabian Sea (Gonu 2007) cannot detach and initiate the transport of these boulders to their final position. However, a tsunami wave of 3.5-m wave height can easily detach and mobilize these boulders to their final position. On the basis of imbrication direction, we postulate that the direction of source of tsunami wave is southwesterly. Owing to the strike-slip nature of Owen Fracture Zone and earlier documented large landslides along the Southern Owen Ridge, we postulate the most likely source of this tsunami wave could be a mega submarine landslide along the Southern Owen Ridge.

Major solar eruptions and high-energy particle events during solar cycle 24

We report on a study of all major solar eruptions that occurred on the front-side of the Sun during the rise to peak phase of cycle 24 (first 62 months) in order to understand the key factors affecting the occurrence of large solar energetic particle events (SEPs) and the ground levels enhancement (GLE) events. The eruptions involve major flares with soft X-ray peak flux >/= 5.0 x10-5 Wm-2 (i.e., flare size >/= M5.0) and accompanying coronal mass ejections (CMEs). The selection criterion was based on the fact that the only front-side GLE in cycle 24 (GLE 71) had a flare size of M5.1. Only ~37% of the major eruptions from the western hemisphere resulted in large SEP events. Almost the same number of large SEP events was produced in weaker eruptions (flare size <M5.0), suggesting that the soft X-ray flare is not a good indicator of SEP or GLE events. On the other hand, the CME speed is a better indicator of SEP and GLE events because it is consistently high supporting the shock acceleration mechanism for SEPs and GLEs. We found the CME speed, magnetic connectivity to Earth, and ambient conditions as the main factors that contribute to the lack of high energy particle events during cycle 24. Several eruptions poorly connected to Earth (eastern-hemisphere or behind-the-west-limb events) resulted in very large SEP events detected by the STEREO spacecraft. Some very fast CMEs, likely to have accelerated particles to GeV energies, did not result in a GLE event because of poor latitudinal connectivity. The stringent latitudinal requirement suggests that the highest energy particles are likely accelerated in the nose part of shocks. There were also well-connected fast CMEs, which did not seem to have accelerated high energy particles due to possible unfavorable ambient conditions (high Alfven speed, overall reduction in acceleration efficiency in cycle 24).

Petrographic Characteristics of the Proterozoic Vempalle Carbonates, Cuddapah Basin, India and their Implications

Abstract: The Vempalle Formation of the Proterozoic Cuddapah basin has a well developed sequence of carbonate rocks, which are interbedded with shales, siltstones and chert. The stromatolitic carbonates are conspicuous at many places but the oolitic carbonates are less prominent and are present only in some areas. All the carbonates are pervasively dolomitized. Petrographic examination of these carbonates revealed that they are predominantly made up of fine grained micrite with patchy development of sparite and chert/quartz. The stromatolitic carbonates show distinct banding of alternate carbonate and cherty layers. The latter are rich in organic matter indicating prevalence of profuse biogenic activity. The oolitic carbonates comprise of ooids showing both concentric and radial patterns and made up of carbonate/ chert and cemented by micro/mega quartz or carbonate itself. Diagenetic and post depositional features are reflected in cementation, recrystallization, compaction, stylolite formation and silicification processes. Various stages of cementing material are observed. Secondary vein fillings of carbonate or quartz traverse the carbonate/cherty groundmass. Intraclasts present suggest occasional erosional destruction of associated sediments, short lived transport and local redeposition. Accessory silicate minerals represent terrigenous influx during deposition. Dolomitization of the carbonates was fabric retentive and early diagenetic. The environmental conditions were characterised by low energy, within a shallow water zone, in occasional higher energy events and turbulence. The carbonates appear to have been deposited on a shallow water ramp within a tidal regime.

Flavor composition of the high-energy neutrino events in IceCube.

The IceCube experiment has recently reported the observation of 28 high-energy (>30 TeV) neutrino events, separated into 21 showers and 7 muon tracks, consistent with an extraterrestrial origin. In this Letter, we compute the compatibility of such an observation with possible combinations of neutrino flavors with relative proportion (αe:αμ∶ατ)⊕. Although the 7∶21 track-to-shower ratio is naively favored for the canonical (1∶1∶1)⊕ at Earth, this is not true once the atmospheric muon and neutrino backgrounds are properly accounted for. We find that, for an astrophysical neutrino E(-2) energy spectrum, (1∶1∶1)⊕ at Earth is disfavored at 81% C.L. If this proportion does not change, 6 more years of data would be needed to exclude (1∶1∶1)⊕ at Earth at 3σ C.L. Indeed, with the recently released 3-yr data, that flavor composition is excluded at 92% C.L. The best fit is obtained for (1∶0∶0)⊕ at Earth, which cannot be achieved from any flavor ratio at sources with averaged oscillations during propagation. If confirmed, this result would suggest either a misunderstanding of the expected background events or a misidentification of tracks as showers, or even more compellingly, some exotic physics which deviates from the standard scenario.

Taphonomy and ichnology: tools for interpreting a maximum flooding interval in the Berriasian of Tlemcen Domain (Western Tellian Atlas, Algeria)

During the Middle-Late Berriasian, a long-term climatic and eustatic change occurred, documented in the literature. However, data from the northern Gondwana paleomargin are scarce. This research analyzes the Lamoriciere Clay Formation at the Ouled Mimoun section, focusing on fossil assemblages and using taphonomic and ichnological aspects to interpret a transgressive–regressive cycle. The section starts with mudstones and oolitic grainstones representing shallow-water environments in the top part of the Ouled Mimoun Marly Limestones Formation (Upper Tithonian p.p. to lowermost Berriasian). The base of the Lamoriciere Clay Formation is characterized by a high clay content but was still deposited in shallow water, as indicated by the record of the ostracod Asciocythere, dasyclad green algae, and the sponge Cladocoropsis. The subsequent record of fossil-rich calcareous beds at the beginning of the Upper Berriasian (Boissieri Zone) with ammonoids and calpionellids is congruent with an increase in water depth. The sedimentation rate in the Late Berriasian was reduced, as indicated by the increment of fossil remains and trace fossils. Ammonoid moulds show taphonomic features pointing to long-lasting exposure on the sea floor prior to burial with corrasion and encrustation by sessile organisms such as serpulids, thecideidinids, and bryozoans. During calm periods, crustaceans and worms intensely burrowed the sea floor. The record of Thalassinoides and Rhizocorallium indicates bottom conditions ranging from soft to firm. The low sedimentation rate and sediment by-passing probably favored early lithification. The increasing carbonate content as well as decreasing sedimentation rate is compatible with the maximum distance to emerged areas during maximum flooding. High-energy events, probably related to storms, favored the exhumation and extreme corrasion of ammonite moulds and trace fossils. In the resulting substrate, limonitic films developed and encrusting organisms proliferated (serpulids, bryozoans, and thecideidinids), colonizing both the bottom surface (hardground) and exhumed moulds of ammonoids and Thalassinoides. The uppermost 0.7 m of the section represents the return to shallow conditions, with increasing sedimentation rate and terrigenous detrital content, along with the disappearance of hemipelagic forms (ammonoids); hence it is interpreted as having developed at the beginning of a regressive context.

Reconstructing Anthropocene extreme flood events by using litter deposits

Coastal areas are densely populated and therefore vulnerable to the impact of flooding events induced by tsunami waves or storm surges. The flood risk has increased due to global climate change and an accelerated sea-level rise as observed during the most recent geological times (the Anthropocene). At the same time a concentration of settlements along the world's coastlines is observed. Therefore, knowledge of maximum flooding levels during high-energy events is essential to improve the assessment of risk. We utilise wrack lines composed of litter as in situ physical marks made up of durable, solid matter of various compositions to delineate the maximum flooding level. These deposits may enclose information on production dates, used to precisely reconstruct the timing of the flooding. This approach allows an ultra-high resolution dating. We demonstrate the application of this efficient, fast and cheap method for the coastline of Oman bordering the Arabian Sea (Northern Indian Ocean). The area was recently affected by devastating tropical cyclones as well as tsunamis.

AN INTERPRETATION OF GLE71 CONCURRENT CME-DRIVEN SHOCK WAVE

Particle accelerations in solar flares and CME-driven shocks can sometimes result in very high-energy particle events (>= 1 GeV) that are known as ground level enhancements (GLEs). Recent studies on the first GLE event (GLE71 2012 May 17 01:50 UT) of solar cycle 24 suggested that CME-driven shock played a leading role in causing the event. To verify this claim, we have made an effort to interpret the GLE71 concurrent shock wave. For this, we have deduced the possible speed and height of the shock wave in terms of the frequency (MHz) of the solar radio type II burst and its drift rate (MHz min(-1)), and studied the temporal evolution of the particle intensity profiles at different heights of the solar corona. For a better perception of the particle acceleration in the shock, we have studied the solar radio type II burst with concurrent solar radio and electron fluxes. When the particle intensity profiles are necessarily shifted in time at similar to 1 AU, it is found that the growth phases of the electron and cosmic ray intensity fluxes are strongly correlated (>0.91; >= 0.87) with the frequency drift rate of the type II burst, which is also consistent with the intensive particle accelerations at upper coronal heights (similar to >= 0.80 R-S < 1.10 R-S). Thus, we conclude that the CME-driven shock was possibly capable of producing the high-energy particle event. However, since the peaks of some flare components are found to be strongly associated with the fundamental phase of the type II burst, the preceding flare is supposed to contribute to the shock acceleration process.

Preface - Human-altered coastal systems: processes, monitoring, and management

The imperatives of economic development have constantly brought pressure to bear on coasts. In many countries throughout the world, the coast is increasingly destabilized by the construction of tourist infrastructure, routes, and harbours. The lessons accumulated from the destabilization of coasts by massive development, commonly resulting in erosion and costly mitigation solutions, are commonly forgotten or deliberately ignored under the pressures of development. At the same time, increasing human occupation of the coastal zone is resulting in alterations of the coast and aggravating exposure of coastal communities to risks arising from high-energy events, global change, and sea-level rise. This special issue of the Journal of Coastal Conservation and Management brings together experiences on human-altered coasts, through case studies, from several countries, that illustrate links between the physical and human dimensions of coasts that subtend the objectives and activities of the Commission on Coastal Systems (CCS) of the International Geographical Union (IGU). The eight papers in this special issue represent a cross-section of the oral presentations contributed under the banner of the CCS at the IGU conference held in Cologne, Germany, in August 2012. The papers address various aspects of coasts. The importance of a good grasp of the morphodynamic functioning of beaches and dunes prior to forms of management is brought out in the paper by Sedrati and Anthony (2013). The paper by van der Meulen et al. (2014) is a good illustration of how coastal defence can work with nature through dune-building, whereas Tresca et al. (2013) propose an interesting case study of dune growth and dynamics on a seawall. The utility of a sediment budget approach in beach management is brought out in the paper by Psuty et al. (2013). Chadenas et al. (2013) and Musereau and Regnauld (2014) propose studies that highlight the impacts of storms and, the former brings out, in particular, the lessons from the devastating 2010 superstormXynthia. Harley et al. (2013) propose a case study of the utility of coastal video monitoring in analysing nourishment and morphological changes on a gravel beach, and Jeanson et al. (2013) show the various stages of building up a GIS-based coastal observation network and its utility in hazard monitoring. Finally, Brooks and Spencer (2013) has documented the decadal-scale patterns of retreat of soft cliffs. It is intended that the papers will contribute to the corpus of research on human-altered coasts and to ways of mitigating coastal destabilization, in line with the objectives of the Journal of Coastal Conservation and Management.

THE INTRINSIC TWO-DIMENSIONAL SIZE OF SAGITTARIUS A*

We report the detection of the two-dimensional structure of the radio source associated with the Galactic Center black hole, Sagittarius A*, obtained from Very Long Baseline Array (VLBA) observations at a wavelength of 7mm. The intrinsic source is modeled as an elliptical Gaussian with major axis size 35.4 x 12.6 R_S in position angle 95 deg East of North. This morphology can be interpreted in the context of both jet and accretion disk models for the radio emission. There is supporting evidence in large angular-scale multi-wavelength observations for both source models for a preferred axis near 95 deg. We also place a maximum peak-to-peak change of 15% in the intrinsic major axis size over five different epochs. Three observations were triggered by detection of near infrared (NIR) flares and one was simultaneous with a large X-ray flare detected by NuSTAR. The absence of simultaneous and quasi-simultaneous flares indicates that not all high energy events produce variability at radio wavelengths. This supports the conclusion that NIR and X-ray flares are primarily due to electron excitation and not to an enhanced accretion rate onto the black hole.

Search for neutrinoless double-beta decay ofMo100with the NEMO-3 detector

We report the results of a search for the neutrinoless double-$\beta$ decay (0$\nu\beta\beta$) of $^{100}$Mo, using the NEMO-3 detector to reconstruct the full topology of the final state events. With an exposure of 34.7 kg.y, no evidence for the 0$\nu\beta\beta$ signal has been found, yielding a limit for the light Majorana neutrino mass mechanism of $T_{1/2}(0\nu\beta\beta)>1.1 \times 10^{24}$ years (90% C.L.) once both statistical and systematic uncertainties are taken into account. Depending on the Nuclear Matrix Elements this corresponds to an upper limit on the Majorana effective neutrino mass of $< m_{\nu} > < 0.3-0.9$ eV (90% C.L.). Constraints on other lepton number violating mechanisms of 0$\nu\beta\beta$ decays are also given. Searching for high-energy double electron events in all suitable sources of the detector, no event in the energy region [3.2-10] MeV is observed for an exposure of 47 kg.y.

Significance of extreme hydro-geomorphological events in the transformation of mountain valleys (Northern Slopes of the Western Tatra Range, Carpathian Mountains, Poland)

Extreme events disturb the development paths of geomorphological systems. The effect of such events on relief tends to persist for long periods of time and affects the future development of such systems. This paper focuses on changes in middle mountain valleys associated with an extreme hydro-geomorphological event that occurred in the Western Tatra Mountains (Polish Carpathian Mountains) in June of 2007. The geomorphological effects were mapped and an analysis of valley-bottom deposits and dendro-geomorphological data on tree roots and stems was used to identify patterns in the geomorphological transformation taking place during such events. In addition, the organic material obtained from fans was dated by means of carbon-14 dating. The effects of previous extreme events in the study area and their geomorphological outcomes were compared. Four main valley section types were identified in the valley longitudinal profile. Unevenly aged (from 14C 390±30years YBP (1441–1631calAD) to 14C 3760±70 YBP (4318–3962cal BP)) organic material was revealed at different depths of each studied fan. A complex structure with alternating layers of fine and coarse material from the analysed fans was identified. The colluvial-alluvial structure of fans suggests that extreme high-energy events did occur more than once per century during the Holocene. This type of fan structure can be referred to as a patchwork. In the study area, rainfall with high energy potential occurs once in every 6–9 years and extreme hydro-geomorphological events occur every 15years. This type of extreme event may not be exceptional in the history of middle mountain areas.

Dust from collisions: A way to probe the composition of exo-planets?

In order to link infrared observations of dust formed during planet formation in debris disks to mid-infrared spectroscopic data of planetary materials from differentiated terrestrial and asteroidal bodies, we obtained absorption spectra of a representative suite of terrestrial crustal and mantle materials, and of typical martian meteorites.A series of debris disk spectra characterized by a strong feature in the 9.0–9.5μm range (HD23514, HD15407a, HD172555 and HD165014), is comparable to materials that underwent shock, collision or high temperature events. These are amorphous materials such as tektites, SiO2-glass, obsidian, and highly shocked shergottites as well as inclusions from mesosiderites (group A).A second group (BD+20307, Beta Pictoris, HD145263, ID8, HD113766, HD69830, P1121, and Eta Corvi) have strong pyroxene and olivine bands in the 9–12μm range and is very similar to ultramafic rocks (e.g. harzburgite, dunite) (group B).This could indicate the occurrence of differentiated materials similar to those in our Solar System in these other systems.However, mixing of projectile and target material, as well as that of crustal and mantle material has to be taken into account in large scale events like hit-and-run and giant collisions or even large-scale planetary impacts. This could explain the olivine-dominated dust of group B.The crustal-type material of group A would possibly require the stripping of upper layers by grazing-style hit-and run encounters or high energy events like evaporation/condensation in giant collisions. In tidal disruptions or the involvement of predominantly icy/water bodies the resulting mineral dust would originate mainly in one of the involved planetesimals. This could allow attributing the observed composition to a specific body (such as e.g. Eta Corvi).

SU-E-T-81: Comparison of Microdosimetric Quantities Calculated Using the Track Structure Monte Carlo Algorithms Geant4-DNA and NOREC

Purpose: Microdosimetric quantities, such as the lineal energy, have been shown to correlate with the biological response to radiation and the relative biological effect of different radiation types. Track-structure Monte Carlo simulations are an important tool for investigating these responses and for developing mechanistic models to explain them. However, some of the cross-sectional data used in these algorithms has large uncertainties; thus, it is important to investigate how the implementation of the different codes affects the quantities of interest. Methods: Two of the most widely-used publicly available track-structure Monte Carlo codes, Geant4-DNA and NOREC, were used generate electron tracks for two particle sources. One source was a mono-energetic parallel beam of electrons with energies from 5 to 500-keV, and the lineal energy for each track was calculated in 1-mm-spheres arranged in planar arrays at multiple distances from the source. The second source was mono-energetic, uniformly-distributed, and isotropic source, and the lineal energy was scored in a single 30-mm-sphere for energies between 300-eV and 5-keV. Results: The dose-mean lineal energy for the parallel-beam simulations almost all agreed within 5%. For the uniformly-distributed source, at the lowest energies there was strong agreement between the algorithms, but the Geant4-DNA simulations showed slightly more high-energy events for more energetic electrons, but the dose-mean lineal energy agreed to within 4% for all energies. Conclusion: While there were slight differences in the results between the codes, these were consistent with previous studies of the stopping power and angular scattering distributions. Importantly, the computation time for Geant4-DNA was larger than for NOREC, largely due to approximations used in the NOREC for energies below 10-eV. This study shows that these approximation does not have a major impact on the microdosimetry on the energy and length scales investigated.

Archean and paleoproterozoic high-energy impact events and their influence on tectonic evolution of the early Earth in the context of comparative planetology

499 The causeandeffect relations between Precam� brian highenergy impact events and the timevariable rotation regime of the Earth and, consequently, the dependence of the early Earth's evolution trend on these two global processes represent one of the most important fundamental problems of the Earth sci� ences. In this context, this problem has never been considered with due regard for the comparative plane� tology approach. At the same time, these impact events could eventually affect processes of the tectonic evolution of the Earth (4), since the energy produced by the impact of a single asteroid 15-20 km across is

Laser cosmology

Recent years have witnessed tremendous progress in our understanding of the cosmos, which in turn points to even deeper questions to be further addressed. Concurrently the laser technology has undergone dramatic revolutions, providing exciting opportunity for science applications. History has shown that the symbiosis between direct observations and laboratory investigation is instrumental in the progress of astrophysics. We believe that this remains true in cosmology. Current frontier phenomena related to particle astrophysics and cosmology typically involve one or more of the following conditions: (1) extremely high energy events;(2) very high density, high temperature processes; (3) super strong field environments. Laboratory experiments using high intensity lasers can calibrate astrophysical observations, investigate underlying dynamics of astrophysical phenomena, and probe fundamental physics in extreme limits. In this article we give an overview of the exciting prospect of laser cosmology. In particular, we showcase its unique capability of investigating frontier cosmology issues such as cosmic accelerator and quantum gravity.

Spatial distribution of storm wave energy dissipation for the assessment of beach morphodynamics

ABSTRACT Guisado-Pintado, E., Malvarez, G., Navas, F., Carrero, R., 2014. Storms based morphodynamics from wave energy dissipation for beach characterisation. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 259–265, ISSN 0749-0208. High energy events are responsible for most significant and visible changes in beach morphology and sediment disposal in a short temporal scale. Storms are associated with damage to the coastal ecosystem and societal services such as severe shoreline erosion, collapse of coastal infrastructures and properties (ports, seawalls). These also affect the effectiveness of coastal defence works such as beach nourishment. In a scenario of climate change, with predictions of sea level rise and an increase in storminess being the most important threats affecting the coastal environments, the understanding of wave climate and the role of high energy events are of key ...

Morphodynamic characterization of beaches on a Pacific atoll island: Tetiaroa, French Polynesia

Jeanson, M., Anthony, E.J., Etienne, S., Dolique, F., 2014. Morphodynamic characterization of beaches on a Pacific atoll island: Tetiaroa, French Polynesia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 176–181, ISSN 0749-0208.Beach profile types and wave characteristics were monitored in April 2013 on the small islet of Onetahi in the south Pacific coral reef atoll of Tetiaroa, French Polynesia, with the aim of characterizing atoll islet beach morphodynamics. Twelve beach profiles were each surveyed using a theodolite, and water levels and wave characteristics measured over four semi-diurnal tidal cycles using four miniature pressure sensors deployed in the subtidal zone. Water levels corresponded to a very narrow microtidal range (~0.2 m). Wave heights were extremely low throughout (<0.15 m), and spectral decomposition showed a mix between gravity and infragravity energy. The latter dominant at high water, whereas energy was virtually nil at low tide. The wave characteristics, which reflect significant filtering of large Pacific waves by the atoll reef, were not in phase with the intertidal beach morphology. These were interpreted as largely inherited from differential exposure to higher-energy events that occasionally impacted the atoll, notably Cyclone Oli in February 2010. Sand aprons in the lagoon, moving from the eastern to the southern and ultimately the western shores of the island in response to wave pumping, locally enhance build-up of the lower beach where shoreline orientation changes. Confrontation of these observations with long-term islet shoreline trends identified by Le Cozannet et al. (2013) suggests that high-energy event-scale changes and daily background beach cosmetic changes associated with subtidal sand apron mobility, and intertidal swash reworking during the narrow tidal excursion are embedded in long-term morphological stability likely hinged on sand circulation around the islet.

Clustering of mining-induced seismic events in equivalent dimension spaces

High energy release during seismic events induced by mining operation is one of the major dangers perturbing production in underground mines. In this work, temporal changes of seismic event parameters for one of the Rudna Mine (Poland) panels are investigated. The study aim was to find whether the temporal clustering of smaller events in different parameters can be observed before and after the high energy events (Ml ≥ 3) in the mining panel. The method chosen for analysis was the study of temporal variation of fractal dimension of the seismic events parameter sets composed from: the interevent epicentral distance (dr), logarithm of seismic energy (lE), and interevent energy coefficient (dlE), which is the absolute difference between logarithms of energy of two consecutive events. Temporal variations study was performed in equivalent dimension (ED) space. The transformation of the seismic source parameters into ED space allowed to estimate and compare the temporal changes of the fractal dimension of different parameter spaces using the same method—correlation fractal dimension, and then easily compare the obtained temporal changes of fractal dimension of different parameter sets. The effect of grouping is expressed by decrease of fractal dimension, which is connected with the similarity of events parameter values. The temporal changes of the fractal dimension of seismicity before the strong induced events would indicate some initiation phase of the process leading to the high energy release. In the case of the studied Rudna Mine panel, the temporal behavior of the fractal dimension values in different parameter spaces before seismic events showed significant changes before three out of four events with CLVD dominant source mechanisms.

Integrated diagenetic and sequence stratigraphy of a late Oligocene–early Miocene, mixed-sediment platform (Austral Basin, southern Patagonia): Resolving base-level and paleoceanographic changes, and paleoaquifer characteristics

A condensed (~20-m-thick) marine transgressive-highstand succession comprises the upper San Julián Formation (upper Oligocene–lower Miocene) of the northern retroarc Austral Basin, southern Patagonia. Mixed-sediment facies identify a shelf-interior setting, part of an overall warm-temperate regional platform of moderate energy. Giant oyster-dominated skeletal–hiatal accumulations along the maximum flooding surface and forming high-energy event beds in the highstand succession preserve relict micrite in protected shelter porosity, and identify periods of reduced sediment accumulation. The stratigraphic distribution of marine-derived glaucony and diagenetic carbonates is spatially related to sequence development. Depositional siderite coincides with prominent marine transgression, defining transient mixing of marine and meteoric waters across coastal-plain deposits. Chemically evolved autochthonous glaucony coincides with periods of extended seafloor exposure and transgressions that bracket the marine succession, and within the oyster-dominated skeletal accumulations. Seafloor cement, likely once magnesian calcite, formed in association with an encrusting/boring biota along the maximum flooding surface in concert with incursion of cool (11–13°C) water. The cement is present locally in skeletal event beds in the highstand succession suggesting a possible association with high-order base-level change and cooler water. As the highstand succession coincides with elevated global sea level in the late Oligocene–early Miocene, the locally marine-cemented glauconitic skeletal event beds in the highstand succession may identify higher order glacio-eustatic control. Local stratal condensation, however, is best explained by regional differences in basement subsidence. In the burial realm, carbonate diagenesis produced layers of phreatic calcrete coincident with skeletal-rich deposits. Zeolite (clinoptilolite-K) cement is restricted to the lowermost marine transgressive interval probably due to initial elevated metastability of reworked weathered silicates. Clay (illite)-cement is restricted to siliciclastic-rich intervals wherein skeletal carbonate did not buffer pore-water pH. Diagenetic carbonate geochemistry (Sr, Na, and δ18O and δ13C) shows that, with burial, the transgressive and highstand system tracts developed as distinct paleoaquifers resulting from different proximities to meteoric recharge zones.