Geolunch seminar @ UiB

Pr Renato de Paes Almeida
2019-11-13 12:15 - 13:00 (Europe/Oslo) | Kontinentalsokkelen (2G16e), Realfagbygget, Allégaten 41, Bergen, 5007, Norway

Jhon Meyer Munoz
2019-11-06 00:15 - 13:00 | Kontinentalsokkelen (2G16e), Realfagbygget, Allégaten 41, Bergen, 5007, Norway
Supra-detachment basin – Norwegian passive margin

Raisya Noor Pertiwi
2019-10-30 12:15 - 13:00 | Kontinentalsokkelen (2G16e), Realfagbygget, Allégaten 41, Bergen, 5007, Norway

Felix Halpaap | Seismology
2019-10-23 12:15 - 13:00
Earthquakes track subduction fluids from slab source to mantle wedge sink

Felix Halpaap1, Stéphane Rondenay1, Alexander Perrin2, Saskia Goes2, Lars Ottemöller1, Florian Millet1,3, Håkon Austrheim4, Robert Shaw2 and Thomas Eeken2

1) Department of Earth Science, University of Bergen, Bergen, Norway
2) Department of Earth Science and Engineering, Imperial College London, London, UK
3) Laboratoire de Géologie, Claude Bernard University Lyon, Lyon, France
4) Physics of Geological Processes (PGP), The Njord Centre, Department
of Geosciences, University of Oslo, Oslo, Norway

Subducting plates release fluids as they plunge into Earth’s mantle and occasionally rupture to produce intraslab earthquakes. The relationship between these fluids and earthquakes has been debated. Here we combine new seismic observations and new thermal-petrologic models from the Western Hellenic subduction zone in Greece to investigate the relationship between fluids and earthquakes. From seismic images and relocated hypocentres of deep earthquakes (>35 km), we observe that earthquakes occur in three domains of the subduction zone: in the slab, on the plate interface, and in the mantle wedge. These observations are supported by a systematic difference in focal mechanisms and secondary arrival patterns (caused by the interactions of the local seismic waves with subduction discontinuities) between the domains. By comparing across other subduction zones where mantle wedge earthquakes occur (Greece, Lesser Antilles, E Honshu, New Zealand), we find that earthquakes in these cold slabs effectively track the flow of fluids from their source at >80 km depth to their sink at shallow (<40 km) depth. Between source and sink, the fluids flow updip under a sealed plate interface. In some locations, this seal breaks and fluids escape from the slab, through a vent on the interface, into a dry mantle wedge. Along their migration path, the fluids cause earthquakes in the slab, on the plate interface, and in the overlying mantle wedge, while the forearc slab updip of the vents consistently lacks earthquakes due to being fluid-starved. In eleven years (2006-2017) of detailed observations for Greece, the interface vents persistently hosted only small (Mw ≤ 3.7) earthquakes. Their combined release of seismic moment points to a small (<0.4 %) fraction of coseismic compared to aseismic slip between the plates. However, the vents coincide with the locations of three major earthquakes (Mw 5.7, 6.8, ~7.0) that occurred at unusually large depths on the plate interface (>55 km), suggesting that the vents are relevant for the nucleation of damaging earthquakes.

Carolina Cavalcante
2019-09-18 00:15 - 13:00
When hot orogeny goes samba: the case of the Araçuaí belt, SE Brazil

Kyrre Heldal Kartveit
2019-05-29 12:15 - 13:00
soon…

anonymous
2019-05-22 12:15 - 13:00
soon… This slot is free

Edoseghe Osagiede
2019-05-15 12:15 - 13:00
Selective influence of pre-existing intra-basement shear zones on subsequent rift-related normal faults
Pre-existing intra-basement shear zones can induce mechanical and rheological heterogeneities that may influence rifting and the overall geometry of rift-related normal faults. However, the extent to which physical and kinematic interaction between pre-existing shear zones and younger rift faults control the growth of normal faults is less-well understood. Using 3D reflection seismic data from the northern North Sea and quantitative fault analysis, we constrain the 3D relationship between pre-existing basement shear zones, and the geometry, evolution, and synrift depositional architecture of subsequent rift-related normal faults. We identify NE-SW- and N-S-striking rift faults that define a coeval Middle Jurassic – Early Cretaceous, non-colinear fault network. NE-SW-striking faults are parallel to underlying intra-basement shear zone. The faults either tip-out above or physically merge with the underlying shear zone. For faults that merges with the basement shear zone, a change from tabular to wedge-shaped geometry of the hangingwall synrift strata records a transition from non-rotational to rotational extension faulting, which we attribute to the time of rift fault’s linkage with the shear zone, following downward propagation of its lower tip. N-S-striking faults are oblique to, and offset (rather than link with) intra-basement shear zones. These observations highlight the selective influence pre-existing intra-basement shear zones have on evolving rift-related normal faults.

Stéphane Rondenay
2019-05-08 12:15 - 13:00
A preview of the Bergen Arcs Seismic Experiment (BASE) and how the data collected will be automatically processed
In this talk, I will give an overview of the Bergen Arcs Seismic Experiment (BASE), which is currently ongoing and aims to image the deep structure associated with the Bergen Arcs and Hardangerfjord Shear Zone. Though we don’t have any images to show yet (the stations are still in the field), I will discuss how we plan to analyse the data with an automated processing scheme that was developed as part of project GLImER – a global database of teleseismic Receiver Functions that allows us to image structure of the crust and upper mantle at continental scale.

Timothy Reston
2019-03-13 12:15 - 13:15 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Detachment faulting during continental breakup and slow/ultraslow seafloor spreading
Detachment faults, apparently gently-dipping long offset normal faults, are observed in some continental rifts, at some rifted margins, and at both slow and ultraslow spreading ridges. Key questions revolve around their angle and mechanics of slip: many papers have suggested that such detachments only ever slipped at high angles and have passively rotated to low angle. In this talk, I will discuss the mechanics of detachment faults at rifted margins, at slow- and ultra-slow spreading ridges.
At rifted margins, detachments include the S reflectors (Galicia and N Biscay margin), the P detachment (Porcupine Basin) and the H detachment (S Iberia Abyssal Plain). The best constrained of these is the Galicia S reflector, imaged by a 3D seismic volume we collected in 2013. The data have been processed through to prestack time migration, subsequently depth-converted, revealing the true 3D geometry of S and its relationship with the overlying block-bounding faults. S is corrugated, confirming it is a slip surface: moving oceanwards the corrugations swing round from E-W to ESE-WNW, suggesting that rifting may have migrated. The faults above S die out and link laterally, requiring several faults to have ben active simultaneously: heave analysis allows us to group the faults into sets of contemporaneous structures. Where the landward-most fault in each set detaches onto S, S is distorted as if the fault continues oceanwards as S, cutting across the more landward and older portions of S. These observations suggest that S formed by some sort of rolling hinge mechanism, in which an apparently continuous detachment comprises the rotated root zones of successive normal faults, each cutting steeply through the hanging wall of the preceding, more landward fault. However, the synrift geometries show that S must have slipped at ~20°, and as noted above, several faults (rather than a single fault) were active simultaneously. We suggest that the latter is a requirement of the 3D nature of the world, and that the former indicates that S only developed once the entire crust had become brittle, allowing mantle hydration and the formation of weak (serpentine?) fault rocks. IODP Proposal 943-Full sets out to test this interpretation, among other aspects of the rifting to breakup, by dating the synrift sequences across the margin.
To the south, a similar detachment (H) in the South Iberia Abyssal Plain is truncated oceanwards by another detachment that exhumes mantle. The wide expanse of mantle that lies oceanward is itself characterized by landward-dipping reflections, which we interpret as the root zone of successive detachments, each of which moves asymmetrically with its hanging wall to be cut by a new fault cutting through its footwall. The same model explains the unroofing of wide expanses of mantle during amagmatic spreading at the Southwest Indian Ridge; kinematic analysis suggest however that these fault must have initiated as very steep structures in marked contrast to S. Seismicity also suggests that oceanic detachments, controlling the formation of oceanic core complexes (e.g 13°20’N, which we investigated during a cruise in 2016), also dip steeply (75-80°) at depth, and thus might have developed from dikes. Thus there appear to be detachment and detachments active during rifting and seafloor spreading.

Sæunn Halldorsdottir
2019-03-06 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Supercritical and superheated geothermal systems in Iceland – Insight from field cases
Deep drilling in high-temperature geothermal systems by the Iceland Deep Drilling (IDDP) project is aimed at increasing the power output of high-temperature geothermal fields by an order of magnitude without increasing their environmental footprints. The drilling of two wells within the project has opened a window to look into the deeper parts of the geothermal systems and study the nature of their roots; that is, their heat sources. The first, drilled in Krafla, unexpectedly encountered magma at only 2.1 km depth and became the world’s hottest production well at the time, yielding more than 450°C superheated steam. The second, drilled in the Reykjanes geothermal field in Iceland, reached a total depth of 4.5 km in January 2017, achieving the main objective of the IDDP project by reaching supercritical conditions.

Zhiyuan Ge
2019-02-20 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
The impact of abrupt and progressive margin tilting upon passive margin salt basins
Zhiyuan Ge1, Michael Warsitzka2, 3, Matthias Rosenau3 and Rob L. Gawthorpe1
1 Department of Earth Science, University of Bergen, Allégaten 41, 5007 Bergen, Norway
2 Institute of Geophysics of the Czech Academy of Sciences, Boční II/1401, 141 31 Prague 4, Czech Republic
3 German Research Centre for Geosciences (GFZ), 14473 Potsdam, Germany

Abstract
Gravitational failure drives thin-skinned salt tectonics in passive margin salt basins where upslope extension is linked to downslope contraction. As one of the main driving mechanisms, the impact of margin tilting is crucial for the structural and kinematic evolution of supra-salt cover deformation. However, the influences of tilting rate on thin-skinned salt tectonics is poorly understood as most modelling studies, either numerical or experimental, use abrupt tilting method. In this study, using a new analogue modelling method enabling progressive tilting monitored with high‐resolution DIC (digital image correlation) system, we investigate how abrupt and progressive margin tilting control the thin-skinned salt tectonic evolution. The results show that abrupt margin tilting allows the extensional structures to develop with largest coverage from very beginning. Afterwards, the extension starts to retreat towards upslope along with the contraction migrating toward the upslope. In contrast, progressive tilting leads to gradual initiation of extension as tilting increases. Extensional structures first occur in the most upslope tip of the basin and gradually migrate downward. The contraction diffuses in a wide area in the downslope first and then localizes on a few, large extensional structures, similar to that of abrupt tilting. Moreover, the pre-kinematic layer thickness have limited influences on the kinematic variation associated with different tilting scenarios. By demonstrating the temporal and spatial variations associated with abrupt and progressive tilting, we suggest that progressive tilting, which is more like to happen in nature, leads to progressive and diachronous development of extensional structures. This contrasts to current models largely based on studies with abrupt tilting where extension structures tend to occur simultaneously.

Mary Ford
2019-02-13 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
The Pyrenean orogen: new insights into plate convergence
Over the last 10 years a number of major research projects have focused on the Pyrenean orogen and adjacent areas. These projects are providing new insights into many aspects of orogenesis. The Pyrenean orogen was created by the convergence of Iberia and Europe from Late Cretaceous to Oligocene. This mountain belt is often considered as a “typical” doubly vergent orogen. However, the orogen is remarkable in several ways. Continent-continent collision was not preceded by subduction of oceanic crust. Instead, subduction of the Iberian crust initiated during convergence. A narrow transtensive hyperextended rift was inverted in two phases, each with a distinct distribution of deformation both in the near and far fields. The rift was abnormally hot and, as convergence started very soon after the end of rifting, an important thermal inheritance impacted both orogen behaviour and foreland basin evolution. Because total convergence was low we can investigate earliest convergence, a phase that is usualy strongly overprinted in high convergence orogens.
Biography: After completing my BSc at the National University of Ireland, Galway I did my PhD at NUI Cork on the structure and stratigraphy of the Variscan foldbelt of SW Ireland, mapping a 70 km transect on a bike. I started to work on the Alpine foreland fold and thrust belt of SE France during a postdoc at Liverpool University with Trevor Elliott and his group. I then held a lectureship at Plymouth Polytechnic for 4 years before taking an Oberassistentin post with John Ramsey at the Geological Institute ETH Zurich. I continued to work principally on the western Alpine arc, focussing on arc dynamics, foreland basin evolution and tectonosedimentary interactions. In 1998 I took a professorship at the Nancy School of Geology, University of Lorraine, France where I remain today. My research projects include the the tectonosedimentary evolution of the Corinth rift, salt tectonics and dynamics of the Pyrenean orogen. I am principally a field structural geologist, mapping stratigraphy and structure on a local and regional scale and collaborating with many colleagues in multidisciplinary projects.

Does climate mitigation trump other concerns?
2019-02-06 12:15 - 17:00
This is not properly speaking a geolunch.
The meeting is held in conjunction with the 2019 Annual national conference on the UN Sustainable Development Goals (SDGs) as a collaboration between Academia Europaea and the UiB Program for Climate and Energy transformation. We hope for a broad audience of academics, people from the energy sector, NGOs and the general public. The meeting takes place at University of Bergen, in the University Aula, Museplass 3, on Wednesday 6th of February 2019 12.15-17.00 (Day “Zero” of the SDG Conference).
Time: 12:15 / 17:00
https://www.uib.no/en/matnat/123389/does-climate-mitigation-trump-other-concerns
Facebook Event:
https://www.facebook.com/events/613511375768990/
—————————————————————————————————————–
This is part of larger event called UiB’s great conference on UN’s Sustainable
Development Goals on the 7th and 8th of February. This year we have a new day
of events on the 6th, called Day Zero. You can attend a number of very
interesting seminars and workshops, all with different approaches to
sustainability. Day Zero is of course free and a truly unique offer. There are
a total of 21 events to choose from, and the themes range widely. Take a look
at the list of events by following the link:
https://www.uib.no/en/sdgconference/120120/day-zero-wednesday-6-february-2019
Hope you have a nice day, and that you learn a lot from the many events at our
university on February the 6th.
With best regards
Rector Dag Rune Olsen

Thomas Thuesen
2019-01-30 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Source-to-sink in a western Norwegian fjord: How does landslides, floods and grinding glaciers influence sediment supply in the Holocene?
Thomas Thuesen, William Helland-Hansen, Christian Haug Eide, Haflidi Haflidason, Atle Nesje

Western Norwegian fjord-valley systems represent archives of changes in sedimentary processes, and typically exhibit a pronounced change in depositional environment related to the transition from glacial to interglacial conditions. During a glacial situation, the fjord-valley system is emptied of its sediments and further deepened by sub-glacial erosion, both removing sediments and increasing accommodation space. This process is thought to excavate almost all sediments within a fjord-valley system, indicating that most of the sediments in the fjord today have been deposited during and after the retreat of the last glacial ice sheet. Western Norwegian fjord basins typically represent a depositional system where turbidity currents, avalanches and slides interplay with glacimarine and hemipelagic sedimentation.
Here, we present results from a cruise with R/V G.O. Sars to Fjærlandsfjorden in 2018, where several sediment cores, TOPAS high-resolution seismic profiles (<30 cm vertical resolution), and bathymetric data was collected. Fjærlandsfjorden is a 27 kilometers long tributary fjord of Sognefjorden in Western Norway. The fjord-valley system is located just southwest of Jostedalsbreen, and covers an area of about 300 km2. The sediment cores are examined using several instruments (XRF, MSCL and CT-scanning) and sedimentological methods, including dating using radiometric methods (14C AMS).
The data reveal that the Fjærlandsfjorden basin infill consists of basal till, overlain by a thick, acoustically well-laminated glacimarine unit (up to a maximum of ~105 metres in thickness), occasionally disrupted by acoustically transparent lenses interpreted to be avalanche deposits. A 2-3 metre thick hemipelagic unit drapes the glacimarine unit. Seismic and bathymetry data also give evidence of massive avalanche deposits, the largest one measuring up to a minimum volume of 5 million cubic metres. Within the sediment cores several layers interpreted to be related to flooding events can be observed. Preliminary 14C dating indicate a sedimentation rate of 6.5 mm/yr for the prodelta basin.

Atle Rotevatn
2018-12-19 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
How do normal faults grow?
In this geolunch talk, Atle will tell us about how he and some of his friends/co-authors decided to have a stab at figuring out how normal faults actually grow while he was on sabbatical in New Zealand. As you may or may not know, there has been two dominating world views on how normal faults grow. In the simplest terms these are the two models: The first model claims that when faults accumulate displacement they also lengthen by tip propagation – this is a nice way to explain the good correlation between displacement (D) and length (L) over several orders of magnitude.
The second model claims that faults first lengthen very quickly and subsequently accumulates displacement without further lengthening of the faults; critics of this model may argue that it disagrees with D-L scaling, but as will be shown in this talk it actually does not. Anyway, during his stay in NZ Atle and his friends stated digging through lots of published fault data, replotting their growth paths in D-L space. They also added data from faults from analogue models to compare with the natural faults. The results were very interesting indeed – so interesting that they were published in JSG recently
(https://www.sciencedirect.com/science/article/pii/S0191814118304103). Atle will tell us more about this in the talk – but also about how some great discussions came about from showing their data on Twitter for the whole geotweep community to see before any of it was published. These discussions led to revisions to the paper and is an example of how social media can be used not only for outreach, but also for peer-review and scientific discussion.

Bjørn Burr Nyberg
2018-12-12 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Evolution of sedimentary systems with human activity
Society develops in response to sedimentary systems. At the same time these systems are increasingly modified by society. For example, management of hydrological systems to meet water resource demands (e.g., dams, canals, weirs, etc…) reduces and restricts sediment supply to deltas and floodplains, thus increasing vulnerability of population, infrastructure and agricultural land to future flood events, land retreat and sea-level rise. In response, water diversion, land reclamation, river, barrier and coastal armouring are a few of the numerous techniques used to manage and protect coastal and deltaic sedimentary environments to preserve human livelihoods. Given that nearly a third of the world’s population, ~22% of the world’s cropland and ~21% of the world’s pastures are supported by sedimentary systems that cover no more than 16% of Earths landsurface, it is imperative to study the influence of anthropogenic activity on sedimentary systems. However, relatively little is known from a global and quantitative perspective on the extent of the anthropogenic activity on sedimentary systems, and vice versa.
Here we show how recent advances in analyzing the spatial-temporal change in 30 years of satellite imagery by the Google Earth Engine can highlight anthropogenic influence on the surface geomorphology of sedimentary systems. Focusing on deltaic environments, the historical imagery show that upstream capture in water by dam constructions has a direct and observable impact on the propagation of downstream sedimentary successions. A decrease in both water discharge and total suspended sediment supply are a primary factor responsible for net land loss in coastal environments. As sea-levels are expected to rise and dam construction predicted to grow, half a billion people living on deltaic environments are of increasing risk to climate change.

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Albanian
Amharic
Arabic
Armenian
Azerbaijani
Basque
Belarusian
Bengali
Bosnian
Bulgarian
Catalan
Cebuano
Chichewa
Chinese (Simplified)
Chinese (Traditional)
Corsican
Croatian
Czech
Danish
Dutch
English
Esperanto
Estonian
Filipino
Finnish
French
Frisian
Galician
Georgian
German
Greek
Gujarati
Haitian Creole
Hausa
Hawaiian
Hebrew
Hindi
Hmong
Hungarian
Icelandic
Igbo
Indonesian
Irish
Italian
Japanese
Javanese
Kannada
Kazakh
Khmer
Korean
Kurdish
Kyrgyz
Lao
Latin
Latvian
Lithuanian
Luxembourgish
Macedonian
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Malay
Malayalam
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Maori
Marathi
Mongolian
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Norwegian
Pashto
Persian
Polish
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Romanian
Russian
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Serbian
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Thilo Wrona
2018-12-05 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
The Dolomite Problem (i.e. the question of how the large quantities of dolomite observed in the geological record formed in the absence of equivalent modern environments).

Bjørn Nyberg
2018-11-28 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
NetworkGT: A GIS tool for Geometric and Topological Analysis of two-dimensional Fracture Networks
Björn Nyberg, Casey Nixon

Dimensions, arrangements, and interactions of individual fractures form fracture networks that control the mechanical and fluid flow properties of rock masses. Here we present NetworkGT, a toolbox designed to efficiently sample, analyse and map the geometrical and topological attributes of two-dimensional fracture networks. The algorithms are available in a familiar ArcGIS framework providing structural geologists an ability to easily map and analyse large fracture network analogs including fracture length distributions, orientations, frequencies and ternary topology plots. We will explore the rationale, methods and applicability of the NetworkGT toolbox in providing new opportunities in analysing the geometry and topology of fracture networks at a range of spatial and temporal scales important for the assessment of water, geothermal, hydrocarbon and/or CO2 reservoir viability. If interest exists, there may be an opportunity for a larger in-house workshop on the NetworkGT package.

Haakon Fossen
2018-11-21 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
The Pan-African Araçuai-West Congo belt (Brazil/W Africa) and why it needs revision, with references to the Caledonides and Himalayas.

Isabel Edmundson
2018-11-14 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Elucidating key controls on column heights across the Snøhvit gas field, Hammerfest Basin, SW Barents Sea
Izzy Edmundson, Atle Rotevatn, Roy Davies, Kjetil Broberg and Graham Yielding

Faults can act as pathways or barriers to fluid flow and so profoundly influence subsurface fluid migration, accumulation, retention and leakage. Assessment of the retention/seal risk of structural hydrocarbon traps depends upon robust knowledge of the capacity of faults to seal or leak fluids. Faults commonly exhibit spatial variability in sealing properties, and can alternate between sealing and leaking through geological time as the fault undergoes dynamic changes in deformation, diagenesis and applied regional or local stresses. However, typical methods that attempt to predict hydrocarbon column heights based on the mechanical sealing properties of the rock, often neglect the complexity of factors that affect fluid flow at faults and fault intersections. Such estimations predict significantly larger column heights than those measured in 18 underfilled discovery boreholes across the Hammerfest Basin.
To investigate this discrepancy between estimated and discovered column heights, fault-seal analysis was performed on five structures within the Snøhvit gas field. Results indicate that all modelled faults are capable of sealing significantly taller hydrocarbon columns than currently in-place, a result that is corroborated by hydrocarbon shows present below the fluid contact. This suggests that across-fault capillary leakage is unlikely to explain the underfilling. Current work now attempts to assess how the roles of fault intersection and reactivation can cause top-seal breach, leading to enhanced permeability and fluid flow. This may not only help to shed some light on why some traps in the Snøhvit gas field are more underfilled than others, but also lead to better estimations of lateral seal risk and hydrocarbon column heights for future prospect analyses.

Jhon Meyer Munoz Barrera
2018-11-07 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Structural configuration of the southern Klakk Fault Complex, mid-Norway. Crustal-scale fault geometry and interaction in basement rift shoulders.

The thinning of continental crust from ~ 30 km to ~ 10 km characterises the necking domain of passive margins. In this domain, crustal-scale faults, denominated as inner and outer necking breakaway, bound this domain from the proximal and distal domains. Growth and interaction of those faults control the regional configuration of the basin, just as sediment generation, routing and deposition for tens of millions of years. We investigate the southernmost part of the Klakk Fault Complex (KFC), which formed during the late Middle Jurassic to earliest Cretaceous, and separated the Frøya High from the Rås Basin in the Mid-Norwegian Continental Shelf. Although there are no studies related to the Klakk fault in this area, the necking domain has been represented as a single necking breakaway complex. We analysed 2D/3D seismic data and well data to identify the fault geometries, their variation along strike and map the syn-rift deposits.
Interaction of 10-35 km long fault plains with NE-SW, N-S and NW-SE trends define the structural configuration of the Southern Klakk Fault Complex. Three fault geometries have been identified, (i) a low-angle concave downward shape that follow a roughly ramp-flat-ramp geometry, (ii) a low-angle concave upward, and (iii) a series of rider blocks with a common abandon detachment, which is cut by a steep fault segment that bounds the Rås basin. BCU marker shows a vertical separation of approximately 5 km in a highly degraded fault scarp. In addition, fault interaction creates a slope with a series of canyons that transported sediments from the uplifted footwall to the Rås basin. The syn-rift sediments were accumulated in mini-basins in the slope and the Rås Basin. Four hydrocarbon plays can be associated with the geometry and interaction of those crustal faults. (i) syn-rift sediments associated with middle Jurassic to lower Cretaceous rift (Fenja Oilfield), (ii) Basement fracture reservoirs (analogue of Utsira High), (iii) Shallow marine sediments in the footwall’s passive flank (Draugen Field), (iv) Sandy Lower Cretaceous post-rift sediments located next to the fault scarp.

Thomas Theunissen
2018-10-24 12:15 - 13:15 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Topography and subsidence during rifting.
Thomas will give us updates about his ongoing work. Sedimentary basins result from the interlinked evolution of drainage area and uplift/subsidence of the continental domain (onshore and offshore). In this presentation, we will discuss the different causes that explain the topography evolution from the proximal to the distal domain of rifted margins during rifting with a focus on the role of mantle exhumation.

Luisa Zuluaga
2018-10-17 12:15 - 13:15 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Status of geothermal research in Europe and beyond: updates from the 6th European Geothermal Workshop in Strasbourg

Luisa was at the 6th European Geothermal Workshop in Strasbourg last week (10-11 October 2018). She will give us feedbacks about it. What is the on-going research: new approaches, methods or data in the fields of deep geothermal reservoirs for energy exploitation.

Christian Haug Eide
2018-10-03 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway

Spyros Sergiou
2018-09-19 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Paleoceanography and Chronostratigraphy of two forthcoming ocean basins during the Upper Quaternary: The Red Sea and Corinth Rifts.
Spyros present ongoing work from his PhD (Red Sea) as well as introduce future work related to the IODP expedition 381 (Corinth). His aim is to compare the Upper Quaternary evolution of these basins through sedimentological, chronological and paleoceanographical/paleoclimatic proxies.

Shuichi Kodaira, JAMSTEC
2018-09-05 00:15 - 13:00 | Auditorium 5, 3rd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
What we have discovered in outer-rise – trench – volcanic arc systems: results from JAMSTEC’s marine geophysical studies
Shuichi Kodaira, JAMSTEC – Kodaira_CV_2018_2pages
Recent advancement of observational, experimental and theoretical studies of seismogenic zones have allowed us to develop a conceptual model of a subduction zone megathrust. The model shows depth-variant slip behaviors, changing from creep/aseismic slip, to seismogenic slip then to aseismic slip through slow slip, with increasing depth along the subduction interface. However, recent striking observations form the 2011 Tohoku-Oki earthquake strongly indicates need to revise the conceptual model. For examples, rapid response marine geophysical studies after the Tohoku-Oki earthquake obtained direct evidences showing large co-seismic slips reaching the trench axis. Another fundamentally important observation we found, as an input to the subduction zones, is structural evidence indicating hydration of oceanic plates entering subduction zones. A series of large-scale seismic profiles, including three 600-km-long profiles extending from the Pacific basin across the outer rise and southern Kuril and Japan trenches, show that Vp is markedly lower and Vp/Vs markedly higher from about 150 km seaward of the trench to the trench axis. These structural variations are stronger along the profiles into the Japan trench, where throws of bending-related extensional faults of an oceanic plate are greater and seismicity in the upper plane of the double seismic zone is remarkably higher than in the Kuril trench. I will also give a review of JAMSTEC’s seismic studies in the Izu-Bonin volcanic island arc, as an out-put form the subduction zone. Resultant seismic images of the volcanic arc show strong along-arc variation which is related to volcanic activities and history.

Cheng-Cheng Wang
2018-06-20 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway

Thilo Wrona
2018-06-13 12:15 - 13:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
Principal component analysis of seismic facies
Thilo Wrona
Seismic facies analyses are fundamental to the study of sedimentary, tectonic and magmatic systems using seismic reflection data. These analyses generally assume that seismic facies are: (1) well defined, (2) distinct and (3) prevalent patterns in the data. Here, we examine these assumptions critically. First, we demonstrate how to extract the main seismic facies from conventional industry seismic reflection data using principal component analysis. Applying principle component analysis on a large number (up to 1 000 000) of windows (150×150 samples) reveals typical seismic facies showing: (1) horizontal, (2) dipping, (3) displaced and (4) crisscrossing reflections. These seismic facies are distinct in the sense that the principal components are orthogonal to one another, i.e. we cannot express any one component as a linear combination of the others. Next, we show that a small number of seismic facies (100) can explain most of the variance in the data (>0.6); an assumption that is critical to seismic facies analyses. Lastly, we show a simple way to map these facies across a seismic section.

Prof. Claudio Valeriano
2018-06-06 13:15 - 14:00 | The usual place, Room 2G16c, 2nd floor, Realfabyyget, 41 Allégaten, Bergen, 5007, Norway
The Mariana mining dam rupture: isotope tracing of the iron rich mud from the largest environmental accident on Nov 2015 along the Doce River and adjacent marine environments.
Prof. Claudio Valeriano
On research gate: here
