Papers by David Fernández-Blanco
Morphotectonic map Kythira Island
Morphotectonic map of Kythira Island in geo-referenced format (Geospatial PDF). Map shows main ge... more Morphotectonic map of Kythira Island in geo-referenced format (Geospatial PDF). Map shows main geologic and geomorphic features, based on 2m-resolution Digital Surface Model developed from Pleiades satellite imagery and fieldwork. Topographic contours are given at 50 m intervals, with color changes every 150 m. Active faults in red have different stroke thickness to show 5 levels of relative offset, and most present fault scarps as corroborated in situ during fieldwork. Marine terraces and the topmost rasa levels are shown in two tones of blue, with a lighter tone for more speculative surfaces (see main text). Bedding measurements are both from this study (TS) and the geological map (GM) of Danamos (1992). Observed onlap contacts between the largest uplited basin and basement are also shown. Yellow stars mark the locations of samples dated by biostratigraphy; orange stars, near Mitata and W of Avlemonas, show location of Van Hinsbergen (2006) sites.
EarthArXiv (California Digital Library), Dec 6, 2017
The Cotentin Peninsula (Normandy, France) displays sequences of marine terraces and rasas, the la... more The Cotentin Peninsula (Normandy, France) displays sequences of marine terraces and rasas, the latter being wide Late Cenozoic coastal erosion surfaces, that are typical of Western European coasts in Portugal, Spain, France and southern England. Remote sensing imagery and field mapping enabled reappraisal of the Cotentin coastal sequences. From bottom to top, the N Cotentin sequence includes four previously recognized Pleistocene marine terraces (T1 to T4) at elevations < 40 m as well as four higher and older rasas (R1 to R4) reaching 200 ± 5 m in elevation. Low-standing marine terraces are not observed in the central part of the Peninsula and a limited number of terraces are described to the south. The high-standing rasas are widespread all over the peninsula. Such strandline distributions reveal major changes during the Late Cenozoic. Progressive uplift of an irregular sea-floor led to subaerial exposure of bathymetric highs that were carved into rocky platforms, rasas and marine terraces. Eventually, five main islands coalesced and connected to the mainland to the south to form the Cotentin Peninsula. On the basis of previous dating of the last interglacial maximum terrace (i.e. Marine Isotopic Stage, MIS 5e), sequential morphostratigraphy and modelling, we have reappraised uplift rates and 3 derived: (i) mean Upper Pleistocene (i.e. since MIS 5e ~ 122 +/-ka, i.e. kilo annum) apparent uplift rates of 0.04 ± 0.01 mm/yr, (ii) mean Middle Pleistocene eustasycorrected uplift rates of 0.09 ± 0.03 mm/yr, and (iii) low mean Pleistocene uplift rates of 0.01 mm/yr. Extrapolations of these slow rates combined with geological evidence implies that the formation of the sequences from the Cotentin Peninsula occurred between 3 Ma (Pliocene) and 15 Ma (Miocene), which cannot be narrowed down further without additional research. Along the coasts of Western Europe, sequences of marine terraces and rasas are widespread (169 preserve the MIS 5e benchmark). In Spain, Portugal, S England and other parts of western France, the sequences morphostratigraphy is very similar to that of Cotentin. The onset of such Western European sequences occurred during the Miocene (e.g. Spain) or Pliocene (e.g. Portugal). We interpret this Neogene-Quaternary coastal uplift as a symptom of the increasing lithospheric compression that accompanies Cenozoic orogenies.
Eos, Transactions American Geophysical Union, Apr 23, 2019
Leonardo DiCaprio (right) and Earth scientist Piers Sellers discuss NASA's climate missions for a... more Leonardo DiCaprio (right) and Earth scientist Piers Sellers discuss NASA's climate missions for a climate change documentary that DiCaprio is producing. Earth scientists can discuss their prepublication research with their colleagues without having to travel using the EarthArXiv preprint resource. Credit: NASA/Goddard/Rebecca Roth, CC BY 2.0
Seafloor expression of the deep structure during initiation of transtensional fault systems, as seen in the North-South fault system of the Alboran Sea, SE Iberia
&amp;amp;lt;p&amp;amp;gt;How fault segments grow and connect in regions with moderate to ... more &amp;amp;lt;p&amp;amp;gt;How fault segments grow and connect in regions with moderate to high seismic activity is key to assess associated hazards. Earthquakes may affect populated areas and can trigger tsunamis that threaten coastal areas and affect marine infrastructures. Regions accommodating relatively slow tectonic deformation may still enclose active fault systems capable of generating moderate to large magnitude earthquakes, albeit at long recurrence intervals (10&amp;amp;lt;sup&amp;amp;gt;3 &amp;amp;lt;/sup&amp;amp;gt;to 10&amp;amp;lt;sup&amp;amp;gt;4&amp;amp;lt;/sup&amp;amp;gt; years). Although the Alboran Sea is currently characterised by slow tectonic deformation and by earthquakes of low to moderate magnitude, large historical and instrumental events have also occurred (i.e., the Almeria 1522 &amp;amp;lt;sub&amp;amp;gt;IEMS98&amp;amp;lt;/sub&amp;amp;gt; VIII-IX or the Al-Idrissi 2016 M&amp;amp;lt;sub&amp;amp;gt;w&amp;amp;lt;/sub&amp;amp;gt; 6.4 earthquakes). This Neogene basin located in the westernmost Mediterranean Sea absorbs most of the convergence between the Eurasian and Nubian plates (3 - 5 mm/year) by means of four tectonic-scale fault systems: the Carboneras and Al-Idrissi left-lateral strike-slip faults, the Yusuf right-lateral strike-slip fault and the Alboran Ridge thrust.&amp;amp;lt;/p&amp;amp;gt;&amp;amp;lt;p&amp;amp;gt;Our study characterises the North-South fault system on the northern Alboran Sea to better understand the kinematics of the region on a larger scale. This system is proposed as the northern termination of the Al-Idrissi fault, and it may be presently evolving due to the transtensional stress field that affects the area. The first step to characterise the fault system has been to elaborate a detailed geomorphological map of the area to describe the identified scarps, their distribution, and structural relations. To achieve this, we have used very high-resolution bathymetric data (1x1 m pixel resolution) acquired with an autonomous underwater vehicle. The bathymetry shows several fault scarps striking N-S, resulting in horst and graben systems. The second step has involved the interpretation of high-resolution multichannel airgun and sparker seismic profiles running across the N-S faults. The integration of this dataset allows us to relate the morphological scarps with different normal faults interpreted in the seismic profiles. These faults cut the post-Messinian seismostratigraphic units (last 5.3 Ma) up to the seafloor, which supports that the fault system is currently active. Finally, the high segmentation of the North-South fault system and its small accumulated fault displacements supports it is in its initial stage of evolution.&amp;amp;lt;/p&amp;amp;gt;
EarthArXiv (California Digital Library), Jan 10, 2019
It is unclear how the crustal-scale erosional exhumation of continental domains of the Moroccan A... more It is unclear how the crustal-scale erosional exhumation of continental domains of the Moroccan Atlantic margin and the excessive subsidence of its rifted domains affected the Late Jurassic-Early Cretaceous postrift evolution of the margin. To constrain the km-scale exhumation, we study the structural evolution of the Jbel Amsittene. This anticline is located on the coastal plain of the Moroccan Atlantic margin, and is classically considered to have been developed initially by halokinesis in the Late Cretaceous and by contraction during the Neogene. Our structural analysis indicates that the anticline is a fault-propagation fold verging north with Triassic salts at its core and formed by shortening shortly after continental breakup of the Central Atlantic. The anticline grew by NNW-SSE to NNE-SSW contraction, as shown by syntectonic wedges, regional kinematic indicators and synsedimentary structures in Upper Jurassic to Lower Cretaceous rocks. It grew further and tightened during the Cenozoic, presumably in relation to the Atlas/Alpine contraction. Our data and interpretation suggest that "tectonic-drives-salt" in the anticline early evolution, which is coeval with the growth of other anticlines along the Moroccan Atlantic margin and widespread km-scale exhumation farther onshore. Anticline growth due to shortening argues for intraplate far-field stresses potentially linked to the geodynamic evolution of the African, American and European plates.
EarthArXiv (California Digital Library), Jan 10, 2019
Understanding early rifting of continental lithosphere requires accurate descriptions of up-bende... more Understanding early rifting of continental lithosphere requires accurate descriptions of up-bended rift margins and footwalls that ought to correlate in space and time with the elastic flexural uplift that produces them. Here we characterize the geometry of elastic flexural uplift by continental rifting at its spatiotemporal scale in nature (tens of kilometers; 10 4-10 6 years) using geomorphic evidence along the uplifting margin of the Corinth Rift, Greece. Our geomorphic analyses of space-borne topography novelly outline the coherent elastic flexure of continental lithosphere along and across the rift margin and throughout faulting (~10 6 years), as defined by the distribution of footwall uplift south of the active bounding fault. Topography and river drainages outline an elastic flexure signal that increases exponentially toward the bounding fault across the footwall for >50 km and changes in amplitude along the footwall following a parabola that decays from the rift center and has a >60-km wavelength that correlates with rift length. This continental lithosphere up-bend correlates with the scale of the rift, and appears maximum in the center of the rift, where drainage reversal of large catchments suggests rapid slip rates at the bounding fault. This is consistent with the growth of a new, rift-scale, high-angle normal fault. The coherency of elastic flexure in space and time implies highly localized strain in the rift-bounding fault and suggests that the fault transects continental lithosphere with long-term strength. The unparalleled record of flexural uplift and highly localized strain in the landscape of Corinth suggest these processes are intrinsic to early continental rifting elsewhere.
Improved analysis of the marine terraces and rivers of E-Corinth based on high-resolution Pleiades DEMs
EGUGA, Apr 1, 2016
Characterizing the mode of growth in crustal normal faults
EGU General Assembly Conference Abstracts, Apr 1, 2019
Fault flexure and lithospheric rheology set from climate cycles in the Corinth Rift
Geomorphic strain markers accumulating the effects of many earthquake cycles help to constrain th... more Geomorphic strain markers accumulating the effects of many earthquake cycles help to constrain the mechanical behaviour of continental rift systems as well as related seismic hazard. In the Corinth Rift (Greece), the remarkably rich record of onshore and offshore markers of Pleistocene 100ky climate cycles is unique worldwide and makes it a key site to constrain rift mechanics on a large range of timescales. We use high-resolution topography to analyse the 3D geometry of well-exposed and dated Late Pleistocene marine terraces uplifted by flexure on the southern rift shoulder. This dataset is completed offshore with seismic data imaging the flexure across the present-day rift basin. We find 4.5-6.7mm·yr-1 of average slip rate on the master fault over the past ~610ka and an uplift/subsidence ratio of 1:1.2-2.4. To reproduce the uplift and subsidence flexure patterns, we use a 3-layered finite element model at lithospheric scale. Results imply a 40-60° planar normal fault through the e...
Communications earth & environment, Oct 29, 2022
The history of sea level across the Quaternary is essential for assessing past and future climate... more The history of sea level across the Quaternary is essential for assessing past and future climate. Global sea-level reconstructions are typically derived from oxygen isotope curves, but require calibration with geological constraints that are scarce prior to the last glacial cycle (>130 thousand years ago). Here we show that the coral reef terrace sequence at the Huon Peninsula (Papua New Guinea) provides such constraints up to ∼420 thousand years ago, through a geometric analysis of high-resolution topographic data. We derive a northward tectonic tilt as regional deformation pattern, and estimate relative sea level for 31 Quaternary periods, including several periods for which no relative sea level data exists elsewhere. Supported by numerical reef models, these estimates suggest that oxygen isotope-based global mean sea-level curves systematically underestimate interstadial sea-level elevations, by up to ∼20 m. Compared to those curves, our results imply a stronger degree of nonlinearity between ice-sheet volumes and global temperatures within Quaternary glacial cycles.
15 Thermal maturity assessments of hydrocarbon-generation potential and thermal history rarely co... more 15 Thermal maturity assessments of hydrocarbon-generation potential and thermal history rarely consider how 16 upper-plate structures developing during subduction influence the trajectories of accreted sediments. Our 17 thermomechanical models of subduction support that thrusts evolving under variable sedimentation rates 18 and décollement strengths fundamentally influence the trajectory, temperature, and thermal maturity of 19 accreting sediments. This is notably true for the frontal thrust, which pervasively partitions sediments along 20 a low and a high maturity path. Our findings imply that interpretations of the distribution of thermal maturity 21 cannot be detached from accounts of the length and frequency of thrusts and their controlling factors. 22 Taking these factors into consideration, our approach reduces former inconsistencies between predicted and 23 factual thermal maturity distributions in accretionary wedges and provides a first-order predictive indicator 24 for the...
Tektonika, the new Diamond Open Access journal for structural geology and tectonics
&amp;lt;p&amp;gt;&amp;lt;br&amp;gt;Tektonika is a new community-led diamond open-... more &amp;lt;p&amp;gt;&amp;lt;br&amp;gt;Tektonika is a new community-led diamond open-access journal (DOAJ) for structural geology and tectonics. It will join the growing body of DOAJs established over recent years and expand the open science movement within academia. Tektonika is a grass-roots initiative, driven by the enthusiasm and devotion of a wide and diverse spectrum of Earth Scientists from around the globe. This project endeavors to set up an open platform, devoid of any paywall, to publish, disseminate, and promote structural geology and tectonics research, and shape, alongside the other initiatives, the bright future of open access publishing.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;This contribution comes shortly after the official kick-off date of Tektonika and is a great opportunity to provide an overview of our experience setting up a DOAJ and highlight the milestones that have been achieved. These include the selection of executive and associate editorial teams, as well as journal policies regarding submissions, peer-review, article types, journal scope, ethos, and relevant guidelines. A shop with journal merchandise has been set to support the journal costs and may also fund other activities, such as mentoring programs, awards, and seminars. Most importantly, Tektonika is currently welcoming submissions as the first diamond (free-to-publish, free-to-read) open-access platform in the fields of tectonics and structural geology.&amp;lt;/p&amp;gt;
The Huon Peninsula (Papua New Guinea) coral reef terraces re-visited with high-resolution topography and modeling
AGU Fall Meeting Abstracts, Dec 1, 2020
Incipient lithospheric collision throughout the East Mediterranean
&amp;lt;p&amp;gt;&amp;lt;br&amp;gt;We propose that lithospheric collision of Afri... more &amp;lt;p&amp;gt;&amp;lt;br&amp;gt;We propose that lithospheric collision of Africa and Eurasia is incipient throughout the entire East Mediterranean. Our evidence confirms the incipient continent-continent collision that has been recently proposed for the Cyprus Arc and showcases how collision is expressed at depth and across the Hellenic Arc. We provide evidence of basin-wide lithospheric-scale collision by coupling, at tectonic scale (1.5M km&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;), quantitative joint analysis of submarine and terrestrial relief, and the interpretation of a compilation of regional vintage multichannel seismic data (&amp;gt;46.000 km), reprocessed with modern techniques. No megathrust surface marking a subduction interplate contact is imaged in any seismic line, and the relief across sedimentary piles is not shaped as mechanically-accreted wedges. Instead, continent-continent collision is expressed across plates in two modes along longitude. In the offshore regions south of Cyprus and Crete, submarine thrust systems with no frontal structure nor imbrication, and lacking latitudinal continuation, record collision stacking basin sediments vertically. Onshore, concurrent uplift and extension are recorded by uplifting strandlines, hanging valleys, and normal faulting, in both continents, and neatly so in the African margin in front of Crete. Joint plate deformation at lithospheric scale is further inferred as wavelengths of relief coherent across both plates. Regions located latitudinally to these collisional sites extrude away obliquely, either rigidly along transpressional systems, as immediately east of Cyprus and Crete, or through flow and halokinesis of Messinian salts, as on the eastern and western sectors of the Mediterranean Ridge. Our evidence typifies incipient lithospheric collision as expressed throughout the East Mediterranean.&amp;lt;/p&amp;gt;
This presentation describes succinctly what elastic flexure of the lithosphere is, and how it is ... more This presentation describes succinctly what elastic flexure of the lithosphere is, and how it is expressed near normal faults, theoretically, in their footwall (with analysis of topography and marine terraces) and in their hanging-wall (with analysis of seismic data)
Evolution of dynamic plate boundaries: Aegean-Anatolian
Raw material demand for photovoltaics 2017 Share of total raw material demand 2017 Iron 17 mt (≈ ... more Raw material demand for photovoltaics 2017 Share of total raw material demand 2017 Iron 17 mt (≈ 1.3 %) Gallium Cadmium * Stoichiometry: Cu(In 0.7 Ga 0.3)Se 2 Table 4: Worldwide production of selected raw materials and production-specific raw material demand in 2013 for CIGS or CdTe thin film photovoltaics (DS
Timing and mechanisms of Hellenic forearc uplift constrained by the E-Crete marine terraces
EGU General Assembly Conference Abstracts, Apr 1, 2018
Using a Data-driven Bayesian Inversion of Fluvial Topography and Marine Terraces to Simultaneously Constrain Surface Process and Tectonic Models
AGU Fall Meeting Abstracts, Dec 1, 2019
Uploads
Papers by David Fernández-Blanco