ORCID Profile
0000-0002-2493-2377
Current Organisations
Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
,
RWTH Aachen University
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Publisher: Copernicus GmbH
Date: 16-02-2021
DOI: 10.5194/GC-2020-49
Abstract: Abstract. In the spring of 2020, as the coronavirus swept across the globe, millions of people were required to make drastic changes to their lives to help contain the impact of the virus. Among those changes, scientific conferences of every type and size were forced to cancel or postpone in order to protect public health. Included in these was the European Geosciences Union (EGU) 2020 General Assembly, an annual conference for Earth, planetary and space scientists, scheduled to be held in Vienna, Austria, in May 2020. After a six-week pivot to an online alternative, attendees of the newly designed EGU20: Sharing Geoscience Online took part in the first geoscience conference of its size to go fully online. This paper explores the feedback provided by participants following this experimental conference and identifies four key themes that emerged from analysis of the questions: what did people miss from a regular meeting and to what extent did going online impact the event itself, both in terms of challenges and opportunities? The themes identified are: connection, engagement, environment, and accessibility and include discussions of the value of informal connections and spontaneous scientific discovery during conferences, the necessity of considering the environmental cost of in-person meetings, and the opportunities for widening participation in science by investing in accessibility. The responses in these themes cover both positive and negative experiences of participants and raise important questions about what conference providers of the future will need to do to meet the needs of the scientific community in the years following the coronavirus outbreak.
Publisher: Springer Science and Business Media LLC
Date: 07-03-2023
Publisher: Oxford University Press (OUP)
Date: 03-2012
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-4162
Abstract: & & Shortening in fold-and-thrust belts can be accommodated with little or substantial basement involvement, with the former, thin-skinned, style arguably being the more common (Pfiffner, GSA Special Paper, 2006). Experimental studies on thin-skinned fold-and-thrust belts have confirmed critical taper theory and have highlighted the roles of bulk rheology, embedded weak layers, d& #233 collement strength, and surface processes in structural evolution. However, analogue models of thick-skinned fold-and-thrust belts are less common, which may be related to practical challenges involved in shortening thick layers of brittle materials. Here we focus on basement fault reactivation, which has been suggested for several fold-and-thrust belts, such as the Swiss Alps, the Laramide belt in North America and the Sierras P eanas in South America, which show evidence of deep-rooted thrust systems, pointing to a thick-skinned style of shortening.& & & & Within an orogenic system, the shortening style may change between thin- and thick-skinned in space (foreland to hinterland) and time. This raises the question how inherited structures from one shortening phase may influence the next. We aim to use analogue experiments of multi-phase shortening to discuss the effects of deep-seated shortening-related inherited structures, such as thrusts and basement topography, on the structural evolution of fold-and-thrust belts.& & & & We employ a push-type experimental apparatus that can impose shortening in both thick- and thin-skinned style. The device has two independently moving backstops, permitting to change between these shortening styles over time, allowing the simulation of multiple contractional scenarios. We start with an initial stage of thick-skinned shortening, followed by either thin- or thick-skinned reactivation. We use quartz sand to simulate crustal materials and microbeads for embedded weak (sedimentary) layers. Surface and lateral strain, as well as topography, is quantified using a high-resolution particle imaging velocimetry and digital photogrammetry monitoring system.& & & & We will present preliminary results of this innovative experimental approach with the objective of discussing to what extent pre-existing conditions in the basement control the geometric, kinematic, and mechanical evolution of thick-skinned and basement-involved thin-skinned tectonics. In this presentation, we hope for a discussion of mechanisms of localisation of shortening in brittle analogue models, of sequences of thin- and thick-skinned deformation expected during multi-phase shortening, and comparisons to ongoing research and natural observations. Questions we aim to discuss are: Can weaknesses and anisotropies within the basement influence and control later structural evolution? Are pre-existing structures, such as thrusts or shear zones within the basement, responsible for subsequent fault nucleation, thin-skinned folding or basement uplift? What role does the rheology of the basement-cover interface play in the reactivation of basement thrusts? Can we model these reactivations with an analogue setup?& &
Publisher: Copernicus GmbH
Date: 30-09-2021
Abstract: Abstract. In the early months of 2020, as the novel coronavirus (COVID-19) swept across the globe, millions of people were required to make drastic changes to their lives to help contain the impact of the virus. Among those changes, scientific conferences of every type and size were forced to cancel or postpone in order to protect public health. Included in these was the European Geosciences Union (EGU) 2020 General Assembly, an annual conference for Earth, planetary, and space scientists, scheduled to be held in Vienna, Austria, in May 2020. After a 6-week period of changing the format to an online alternative, attendees of the newly designed EGU20: Sharing Geoscience Online took part in the first geoscience conference of its size to go fully online. This paper explores the feedback provided by participants following this experimental conference and identifies four key themes that emerged from an analysis of the following questions: what did attendees miss from a regular meeting, and to what extent did going online impact the event itself, both in terms of challenges and opportunities? The themes identified are “connecting”, “engagement”, “environment”, and “accessibility”. These themes include concepts relating to discussions of the value of informal connections and spontaneous scientific discovery during conferences, the necessity of considering the environmental cost of in-person meetings, and the opportunities for widening participation in science by investing in accessibility. The responses in these themes cover the spectrum of experiences of participants, from positive to negative, and raise important questions about what conference providers of the future will need to do to meet the needs of the scientific community in the years following this coronavirus outbreak.
Publisher: Elsevier BV
Date: 11-2016
Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-7974
Abstract: & & A series of influential papers in the 1980& #8217 s showed how the long-term evolution of fold-and-thrust belts and accretionary wedges (here collectively termed orogenic wedges) can quantitatively be described as striving towards a mechanical equilibrium defined by their internal and basal material strengths (Dahlen 1984, Dahlen et al. 1984, Davis et al. 1983). Unstable orogenic wedges will deform to adjust their basal and surface slopes to a critical taper angle, defined by a wedge that is at the verge of failure everywhere. Critical taper theory has been confirmed by analogue and numerical experiments and found numerous successful applications in field studies.& & & & The success of critical taper theory forms a framework that allows investigating non-critical behaviour of orogenic wedges. Previous numerical and analogue studies pointed out that: (1) Only portions of orogenic wedges may be at failure at any given time, separating critically stressed from non-critical segments (Lohrmann et al. 2003, Simpson 2011). As these wedges still observe a critical taper, this may indicate that it is the critically stressed segments that define the overall wedge shape. (2) Numerical experiments often attain a critical taper at lower shortening percentages than analogue experiments. We speculate that this may be related to larger amounts of strain softening generally used in numerical setups and/or the number of shear zones that forms at equivalent shortening (which is controlled by numerical resolution and analogue material properties). This non-criticality is thus likely only a transient state.& & & & We here ask the question whether structural inheritance from earlier compressional or extensional deformation phases may lead to longer-term non-critical wedge behaviour by favouring out-of-sequence thrusting or shear zone propagation into the foreland. To address this question, we combine a review of previous dynamic wedge experiments with new analogue experiments that investigate the influence of inherited shear zones and variations in material properties on wedge evolution. We shorten quartz sand layers overlying a weak basal microbeads layer with a non-deformable backstop. The backstop has two independently moving parts, allowing to alternate thin- and thick-skinned deformation. We find that the reactivation of basement shear zones formed in earlier deformation phases is short-lived and does not affect thrusting to a degree that would distinguish these wedges from those without inheritance. We extend these experiments by including variations in internal material properties and weaker shear zones, remaining however in the domain of brittle orogenic wedges.& & & & Non-critical wedge behaviour may only be a transient state, but could occur frequently owing to variations in material properties or structural inheritance, which are to be expected in regions of inter-plate shortening of former rift regions. Our contribution hopes to highlight the potential for future modelling studies of orogenic wedges to examine how non-critical wedge behaviour could play into the evolution of fold-and-thrust belts and accretionary wedges.& &
Publisher: Elsevier BV
Date: 11-2015
Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-7027
Abstract: & & When orogeny reactivates extensional structures or uplifts pre-existing depocenters in the foreland (inversion), the overall nature, dimension, and geometry of these rheological heterogeneities represent one of the main controlling factors in the spatio-temporal evolution of foreland fold-and-thrust belts. Relationships between inversion structures in the foreland and far-field stresses caused by orogenic fronts have long been identified (e.g., Ziegler, 1989, Geol. Soc. Spec. Publ. 44). However, conditions that facilitate or hinder basin inversion in these settings remain unclear, mainly due to the intrinsic complexity of analysing multiple overprinted geological events.& & & & We use novel laboratory experiments of basin inversion to investigate how compressional stresses are transferred across a heterogeneous crust. More specifically, we determine how the presence of multiple extensional basins in the foreland controls the location, occurrence, and sequencing of foreland thrusts. Quantitative analysis of our experiments allows us to define conceptual models for comparison and application to natural ex les where geological interpretation remains partially conjectural due to their intrinsic complexity, such as the permo-carboniferous troughs beneath the Swiss Molasse basin or the inverted Broad Fourteens Basin in the North Sea.& & & & Our experiments are built in a modelling apparatus with a mobile backstop, using quartz sand to model brittle crustal materials and glass microbeads to simulate a weaker basal detachment layer. Velocity discontinuities at the base are created by attaching multiple thin basal sheets to the mobile wall during extensional phases (pulling). The location of each extensional basin is defined by the lengths of the basal sheets. During extension, the resulting graben-like structures are progressively filled with microbeads to create a sedimentary infill that is less competent than the surrounding rock. The basal sheets are completely detached from the mobile wall before the initiation of the shortening phase (pushing). Topography, surface and lateral deformation is quantified employing a high-resolution particle imaging velocimetry (PIV) system.& & & & We present results of shortening multiple extensional basins at fixed distances from the orogenic front. Detailed analysis shows that extensional basin faults are not reactivated during shortening, but instead inversion is characterised by an initial squeezing of the basin fill and subsequent formation of either frontal or back thrusts that localise along the microbead-sand interface, leading to the overall uplift of the basins. This mechanism occurs independent of the distance of the basin to the orogenic front. However, when several grabens are present, the extent of shortening that each extensional structure localises differs greatly between experiments, showing variability according to the number of basins and their distance to the orogenic front.& & & & When compared to reference models with a homogeneous crust, our results show that the presence of multiple extensional basins in the foreland exerts a first-order control on the evolution of propagating fold-and-thrust belts. Thrust location and sequencing evolve differently, with frontal thrusts developing along pre-existing basins boundaries at early stages, and subsequent stages of back thrust formation characterising wedge thickening at the hinterland of the extensional basins.& &
Publisher: Copernicus GmbH
Date: 19-04-2022
DOI: 10.5194/EGUSPHERE-2022-139
Abstract: Abstract. Continental rifts can form when and where continents are stretched. If the driving forces can overcome lithospheric strength, a rift valley forms. Rifts are characterised by faults, sedimentary basins, earthquakes and/or volcanism. With the right set of weakening feedbacks, a rift can evolve to break a continent into conjugate rifted margins such as those found along the Atlantic and Indian Oceans. When, however, strengthening processes overtake weakening, rifting can stall and leave a failed rift, such as the North Sea or the West African Rift. A clear definition of continental break-up is still lacking because the transition from continent to ocean can be complex, with tilted continental blocks and regions of exhumed lithospheric mantle. Rifts and rifted margins not only shape the face of our planet, they also have a clear societal impact, through hazards caused by earthquakes, volcanism, landslides and CO2 release, and through their resources, such as fertile land, hydrocarbons, minerals and geothermal potential. This societal relevance makes an understanding of the many unknown aspects of rift processes as critical as ever.
Publisher: Elsevier
Date: 2023
Publisher: Geological Society of London
Date: 2006
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-1940
Abstract: & & In the spring of 2020, as the coronavirus swept across the globe, millions of people were required to make drastic changes to their lives to help contain the impact of the virus. Among those changes, scientific conferences of every type and size were forced to cancel or postpone in order to protect public health. Included in these was the European Geosciences Union (EGU) 2020 General Assembly. After a six-week pivot to an online alternative, attendees of the newly designed EGU20: Sharing Geoscience Online took part in the first geoscience conference of its size to go fully online.& br& & & br& This work explores the feedback provided by participants following this experimental conference and identifies four key themes that emerged from analysis of the questions: what did people miss from a regular meeting and to what extent did going online impact the event itself, both in terms of challenges and opportunities?& br& & & br& The themes identified are: connection, engagement, environment, and accessibility and include discussions of the value of informal connections and spontaneous scientific discovery during conferences, the necessity of considering the environmental cost of in-person meetings, and the opportunities for widening participation in science by investing in accessibility.& br& & & br& The responses in these themes cover both positive and negative experiences of participants and raise important questions about what conference providers of the future will need to do to meet the needs of the scientific community in the years following the coronavirus outbreak.& &
Location: Germany
No related grants have been discovered for Susanne Buiter.