ALBERT

Beschreibung: Rincón de Parangueo is a Quaternary maar that has been recently desiccated. The crater was partially occupied by a soda lake, and near the shoreline microbialites have formed. Evaporites (mainly trona and halite) precipitated as the water level dropped. Active subsidence of the lake floor ( c. 24 m since 1980) produced countless structures close to the lakeshore, where deformation is extensional. Closer to the depocentre, in the western half of the basin, gliding/spreading produced folds and mud-injection domes. The most remarkable structure throughout the basin is a monocline that forms a ring-like, nearly continuous scarp, approximately 15 m high, which in the eastern half of the basin was produced as a fault-propagation fold developed above the buried diatreme–country rock boundary. A more diffuse (wider) monocline, locally associated with compressive structures, occurs in the western half of the basin. These structures are interpreted as having developed above a gently inclined, irregular lake sediment–country rock (andesite) interphase. The monocline was modified by high-angle extensional faults/fractures with large heaves/apertures. In the eastern half of the basin, there is a second (outer) scarp, approximately 13 m high, formed by a high-angle, listric, normal fault. Rollover antiforms occur in the hanging wall of this structure. Rincón is an example of centripetal gravitational gliding/spreading.

Beschreibung: RED SEED stands for Risk Evaluation, Detection and Simulation during Effusive Eruption Disasters, and combines stakeholders from the remote sensing, modelling and response communities with experience in tracking volcanic effusive events. The group first met during a three day-long workshop held in Clermont Ferrand (France) between 28 and 30 May 2013. During each day, presentations were given reviewing the state of the art in terms of (a) volcano hot spot detection and parameterization, (b) operational satellite-based hot spot detection systems, (c) lava flow modelling and (d) response protocols during effusive crises. At the end of each presentation set, the four groups retreated to discuss and report on requirements for a truly integrated and operational response that satisfactorily combines remote sensors, modellers and responders during an effusive crisis. The results of collating the final reports, and follow-up discussions that have been on-going since the workshop, are given here. We can reduce our discussions to four main findings. (1) Hot spot detection tools are operational and capable of providing effusive eruption onset notice within 15 min. (2) Spectral radiance metrics can also be provided with high degrees of confidence. However, if we are to achieve a truly global system, more local receiving stations need to be installed with hot spot detection and data processing modules running on-site and in real time. (3) Models are operational, but need real-time input of reliable time-averaged discharge rate data and regular updates of digital elevation models if they are to be effective; the latter can be provided by the radar/photogrammetry community. (4) Information needs to be provided in an agreed and standard format following an ensemble approach and using models that have been validated and recognized as trustworthy by the responding authorities. All of this requires a sophisticated and centralized data collection, distribution and reporting hub that is based on a philosophy of joint ownership and mutual trust. While the next chapter carries out an exercise to explore the viability of the last point, the detailed recommendations behind these findings are detailed here.

Beschreibung: The Sinclair terrane is an important part of the Namaqua orogenic province in southern Namibia containing well-preserved Mesoproterozoic volcano-sedimentary successions suitable for palaeomagnetic and geochronological studies. The Guperas Formation in the upper part of the Sinclair stratigraphic assemblage contains both volcanic and sedimentary rocks cut by a bimodal dyke swarm with felsic members dated herein by U–Pb on zircon at c. 1105 Ma. Guperas igneous rocks yield a pre-fold direction and palaeomagnetic pole similar to that previously reported. Guperas sedimentary rocks yield positive conglomerate and fold tests, with a maximum concentration of characteristic remanence directions at 100% untilting. The combined Guperas data generate a palaeomagnetic pole of 69.8° N, 004.1° E ( A 95 =7.4°, N= 9). The 1105 Ma post-Guperas dykes yield stable remanence directions with positive baked-contact tests and a palaeomagnetic pole at 62.3° N, 031.9° E ( A 95 =6.9°, N= 26), which is coincident with that of the Kalahari-wide Umkondo large igneous province, demonstrating tectonic coherence of the Sinclair terrane with the Kalahari craton at the time of dyke emplacement. These results show that palaeomagnetic and geochronological studies of the Sinclair terrane can provide kinematic constraints on the tectonic evolution of the Namaqua–Natal–Maud orogenic belt and its role in the formation of the Rodinia supercontinent.

Beschreibung: 〈p〉This study gives valuable insights into the microstructure and pore space characteristics of 17 compositionally variable Visean shale samples from the Ukrainian Dniepr-Donets Basin (the ‘Rudov Beds’). The representative imaging area varies considerably (from 10 000 to 〉300 000 µm〈sup〉2〈/sup〉) as a function of the mineralogy and diagenetic overprinting. The pores hosted in organic matter (OM) are restricted to secondary solid bitumen. Based on high-resolution maps from broad ion beam scanning electron microscopy combined with organic geochemical and bulk mineralogical data, we propose that the amount of OM-hosted porosity responds to the availability of pore space, enabling the accumulation of an early oil phase, which is then progressively transformed to a porous solid bitumen residue. The type of OM porosity (pendular/interface v. spongy) is reflected in the individual pore size distributions: the spongy pores are usually smaller (〈/p〉

Beschreibung: 〈p〉The southern Tuaheni Landslide Complex (TLC) at the Hikurangi subduction margin displays distinctive morphological features along its distribution over the Tuaheni slope offshore Gisborne, New Zealand. We here present first analyses of a gravity core transect that systematically samples surficial sediments from the source area to the toe of this landslide complex, thus providing important new insight into shallow lithological variation in the slide complex. Geophysical and geochemical core logs and core descriptions form the basis for a characterization of representative sediment successions that are indicative of the respective slope segment of recovery. Our results show that the lithology of surficial sediments varies significantly along the length of the landslide complex. Depending on the slope segment observed, this variation includes post-Last Glacial Maximum (LGM) outer-shelf sediments, and hemipelagic drape and near-surface reworked debris avalanche deposits, as well as multiple intercalated thinner turbidites and tephra layers at the distal end of the profile. Lithological downslope variability suggests ongoing mass transport events through the late Holocene that were likely to have been limited to small mud-turbidite flows. Integration with acoustic sub-bottom imagery reveals the presence of multiple stacked mass-transport deposits at depth, contrasting with previous interpretations of a single parent failure.〈/p〉 〈p〉〈b〉Supplementary material:〈/b〉 MSCL and XRF core-log data are made available through the PANGAEA database 〈a href="https://doi.pangaea.de/10.1594/PANGAEA.883867"〉https://doi.pangaea.de/10.1594/PANGAEA.883867〈/a〉〈/p〉

Beschreibung: 〈p〉The Queen Charlotte Fault defines the Pacific–North America transform plate boundary in western Canada and southeastern Alaska for 〈i〉c.〈/i〉 900 km. The entire length of the fault is submerged along a continental margin dominated by Quaternary glacial processes, yet the geomorphology along the margin has never been systematically examined due to the absence of high-resolution seafloor mapping data. Hence the geological processes that influence the distribution, character and timing of mass transport events and their associated hazards remain poorly understood. Here we develop a classification of the first-order shape of the continental shelf, slope and rise to examine potential relationships between form and process dominance. We found that the margin can be split into six geomorphic groups that vary smoothly from north to south between two basic end-members. The northernmost group (west of Chichagof Island, Alaska) is characterized by concave-upwards slope profiles, gentle slope gradients (2 and display scarp heights between 10 and 250 m. Transpression along the Queen Charlotte Fault increases southwards and the slope physiography is thus progressively more influenced by regional-scale tectonic deformation. The southernmost group (west of Haida Gwaii, British Columbia) defines the tectonically dominated end-member: the continental slope is characterized by steep gradients (〉20°) along the flanks of broad, margin-parallel ridges and valleys. Mass transport features in the tectonically dominated areas are mostly observed along steep escarpments and the larger slides (up to 10 km〈sup〉2〈/sup〉) appear to be failures of consolidated material along the flanks of tectonic features. Overall, these observations highlight the role of first-order margin physiography on the distribution and type of submarine landslides expected to occur in particular morphological settings. The sediment-dominated end-member allows for the accumulation of under-consolidated Quaternary sediments and shows larger, more frequent slides; the rugged physiography of the tectonically dominated end-member leads to sediment bypass and the collapse of uplifted tectonic features. The maximum and average dimensions of slides are an order of magnitude smaller than those of slides observed along other (passive) glaciated margins. We propose that the general patterns observed in slide distribution are caused by the interplay between tectonic activity (long- and short-term) and sediment delivery. The recurrence ( 7 earthquakes along the Queen Charlotte Fault may generate small, but frequent, failures of under-consolidated Quaternary sediments within the sediment-dominated regions. By contrast, the tectonically dominated regions are characterized by the bypass of Quaternary sediments to the continental rise and the less frequent collapse of steep, uplifted and consolidated sediments.〈/p〉

Beschreibung: 〈p〉Submarine landslides represent a major, previously little recognized, geological hazard to the coastal communities. This study investigates the size, depth and degree of submarine landslides along the margins of the Ulleung Basin and examines how the shelf morphology and sediment supply affect the style and occurrence of slope failures. The slopes have experienced at least 38 episodes of submarine failures, which have left clear arcuate-shaped scarps that initiate at water depths of 150–1120 m. Individual landslides comprise volumes over the range 0.1–340 km〈sup〉3〈/sup〉, cover 20–800 km〈sup〉2〈/sup〉 on the seafloor and have runout distances of up to 50 km from the source. The headwall scarps are observed as being in excess of 500 m high. The height of scarps in the southern margin is significantly larger than in the western margin. Moreover, the volume of mass-transport deposits in the southern margin is also much higher compared to those from the western margin. The occurrence of the broad shelf (30–150 km wide) and high sedimentation rates in the southern margin might have led to large-scale slope failures. In contrast, the narrow shelf (〈/p〉

Beschreibung: Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to fine-grained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies.

Beschreibung: This study gives valuable insights into the microstructure and pore space characteristics of 17 compositionally variable Visean shale samples from the Ukrainian Dniepr-Donets Basin (the ‘Rudov Beds’). The representative imaging area varies considerably (from 10 000 to 〉300 000 µm 2 ) as a function of the mineralogy and diagenetic overprinting. The pores hosted in organic matter (OM) are restricted to secondary solid bitumen. Based on high-resolution maps from broad ion beam scanning electron microscopy combined with organic geochemical and bulk mineralogical data, we propose that the amount of OM-hosted porosity responds to the availability of pore space, enabling the accumulation of an early oil phase, which is then progressively transformed to a porous solid bitumen residue. The type of OM porosity (pendular/interface v. spongy) is reflected in the individual pore size distributions: the spongy pores are usually smaller (〈50 nm) than the pendular or OM–mineral interface pores. The OM-hosted porosity coincides with differences in the composition of the extract, with high amounts of extractable OM and saturated/aromatic compound ratios indicative of abundant porous solid bitumen. The average circularity and aspect ratio of the mineral matrix pores correlate with the corresponding values for the OM-hosted pores, which show a preferred bedding-parallel orientation, suggesting that compaction influenced both types of pore.