Fault-controlled asymmetric landscapes and low-relief surfaces on Vestvågøya, Lofoten, North Norway: inherited Mesozoic rift-margin structures?

Source at https://dx.doi.org/10.17850/njg98-3-06The Lofoten Ridge is an integral basement horst of the hyperextended continental rift-margin off northern Norway. It is a key area for studying onshore–offshore rift-related faults, and for evaluating tectonic control on landscape development along the North Atlantic margin. This paper combines onshore geomorphological relief/aspect data and fault/fracture analysis with offshore bathymetric and seismic data, to demonstrate linkage of landscapes and Mesozoic rift-margin structures. At Leknes on Vestvågøya, an erosional remnant of a down-faulted Caledonian thrust nappe (Leknes Group) is preserved in a complex surface depression that extends across the entire Lofoten Ridge. This depression is bounded by opposing asymmetric mountains comprising fault-bounded steep scarps and gently dipping, partly incised lowrelief surfaces. Similar features and boundary faults of Palaeozoic–Mesozoic age are present on the offshore margin surrounding the Lofoten Ridge. The offshore margin is underlain by a crystalline, Permo–Triassic to Early Jurassic, peneplained basement surface that was successively truncated by normal faults, down-dropped and variably rotated into asymmetric fault blocks and basins in the Mesozoic, and the basins were subsequently filled by Late Jurassic to Early Cretaceous sedimentary strata. Comparison of the onshore asymmetric landscapes and offshore tectonic architecture supports the idea that disrupted low-relief surfaces, bounding steep scarps, ridges and depressions onshore the Lofoten Ridge, represent tectonic inheritance of a tilted basement-cover surface, rotated fault blocks and half-graben basins from Mesozoic rifting of the margin. In the Cenozoic, Mesozoic faults controlled the landscape by tilting and reactivated footwall uplift, followed by exhumation of the Mesozoic–Cenozoic cover sediments. Glacial erosion during the Pleistocene partly incised and modified these tectonic features, which nevertheless remain as distinct elements in the landscape

Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial

Background Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain. Methods RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov , NCT00541047 . Findings Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths. Interpretation Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy. Funding Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society

Adding 6 months of androgen deprivation therapy to postoperative radiotherapy for prostate cancer: a comparison of short-course versus no androgen deprivation therapy in the RADICALS-HD randomised controlled trial

Background Previous evidence indicates that adjuvant, short-course androgen deprivation therapy (ADT) improves metastasis-free survival when given with primary radiotherapy for intermediate-risk and high-risk localised prostate cancer. However, the value of ADT with postoperative radiotherapy after radical prostatectomy is unclear. Methods RADICALS-HD was an international randomised controlled trial to test the efficacy of ADT used in combination with postoperative radiotherapy for prostate cancer. Key eligibility criteria were indication for radiotherapy after radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to radiotherapy alone (no ADT) or radiotherapy with 6 months of ADT (short-course ADT), using monthly subcutaneous gonadotropin-releasing hormone analogue injections, daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as distant metastasis arising from prostate cancer or death from any cause. Standard survival analysis methods were used, accounting for randomisation stratification factors. The trial had 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 80% to 86% (hazard ratio [HR] 0·67). Analyses followed the intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov, NCT00541047. Findings Between Nov 22, 2007, and June 29, 2015, 1480 patients (median age 66 years [IQR 61–69]) were randomly assigned to receive no ADT (n=737) or short-course ADT (n=743) in addition to postoperative radiotherapy at 121 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 9·0 years (IQR 7·1–10·1), metastasis-free survival events were reported for 268 participants (142 in the no ADT group and 126 in the short-course ADT group; HR 0·886 [95% CI 0·688–1·140], p=0·35). 10-year metastasis-free survival was 79·2% (95% CI 75·4–82·5) in the no ADT group and 80·4% (76·6–83·6) in the short-course ADT group. Toxicity of grade 3 or higher was reported for 121 (17%) of 737 participants in the no ADT group and 100 (14%) of 743 in the short-course ADT group (p=0·15), with no treatment-related deaths. Interpretation Metastatic disease is uncommon following postoperative bed radiotherapy after radical prostatectomy. Adding 6 months of ADT to this radiotherapy did not improve metastasis-free survival compared with no ADT. These findings do not support the use of short-course ADT with postoperative radiotherapy in this patient population

Table 1. Radiocarbon dated samples from lake basin cores from the Nikel-Kirkenes area

The marine-lacustrine transition (isolation contact) in sediment cores from eight lake basins situated 13.5–72 m a.s.l., in the Norwegian-Russian border area north of Nikel, northwest Russia, was identified based on lithological and diatom analysis, radiocarbon dated, and used to construct a relative sea-level (RSL) curve for the Holocene. All the lakes except one (interpreted as having an unconformable slumped transition) show a regressive I-II-III (marine-transitional-lacustrine) facies succession, indicating a postglacial history of continuous emergence. The RSL curve shows rapid emergence between 10 000 and 8000 BP, very slow emergence between 7000 and 5000 BP, increased rate of emergence between 4500 and 4000 BP, and a moderate rate of emergence after 3500 BP. The low rate of emergence around 6000 BP correlates with the Tapes transgression of more coastal regions, but corresponding sea level, at 25–26 ma. present s.l., lies 5–10 m lower than the elevation predicted based on existing isobase maps for the region. The discrepancy suggests a need for further work in order to more rigorously define and map the Tapes transgression and associated shoreline complex in the northern Fennoscandian-Kola region

(Table 2) Age determination of sediments from lake basins near Polyarny, Russia

A relative sea-level curve for the Holocene is constructed for Polyarny on the Kola Peninsula, northwest Russia. The curve is based on 18 radiocarbon dates of isolation contacts, identified from lithological and diatomological criteria, in nine lake basins situated between 12 and 57 m a.s.l. Most of the lakes show a conformable, regressive I–II–III (marine–transitional–freshwater) facies succession, indicating a postglacial history comprising an early (10,000–9000 radiocarbon years BP) phase of rapid, glacio-isostatically induced emergence (~5 cm/year) and a later phase (after 7000 years BP,) having a moderate rate of emergence (<0.5 cm/year). Three lakes together record a phase of very low rate of emergence or slight sea-level rise at a level of ~27 m a.s.l., between 8500 and 7000 years BP, which correlates with the regional Tapes transgression. Pollen stratigraphy in the highest lake shows that the area was deglaciated before the Younger Dryas and that previously reconstructed Younger Dryas glacier margins along the north Kola coast lie too far nort

Structurally controlled rock slope deformation in northern Norway

Gravitational forcing of oversteepened rock mass leads to progressive failure, including rupture, creeping, sliding and eventual avalanching of the unstable mass. As the point of rupture initiation typically follows pre-existing structural discontinuities within the rock mass, understanding the structural setting of slopes is necessary for an accurate characterisation of the hazards and estimation of the risk to life and infrastructure. Northern Norway is an alpine region with a high frequency of large rock slope deformations. Inherited structures in the metamorphic bedrock create a recurring pattern of anisotropy, that, given certain valley orientations, causes mass instability. We review the geomorphology, structural mechanics and kinematics of nine deforming rock slopes in Troms County, with the aim of linking styles of deformation. The limits of the unstable rock mass follow either foliation planes, joint planes or inherited faults, depending on the valley aspect, slope angle, foliation dip and proximity to fault structures. We present an updated geotechnical model of the different failure mechanisms, based on the interpretations at each site of the review

Visualizing and interpreting surface displacement patterns on unstable slopes using multi-geometry satellite SAR interferometry (2D InSAR)

It is well known that satellite radar interferometry (InSAR) is capable of measuring surface displacement with a typical accuracy on the order of millimeters to centimeters. However, when the true deformation vector differs from the satellite line-of-sight (LOS), the sensitivity decreases and interpretation of InSAR deformationmeasurements becomes challenging. By combining displacement data fromextensive ascending and descending TerraSAR-X datasets collected during the summer seasons of 2009–2014, we estimate two-dimensional (2D) InSAR surface displacement. Displacement data are decomposed into vertical and west/east deformation, dip and combined deformation vector, and validated using Global Navigation Satellite System (GNSS) data.We use the decomposed dataset to visualize variations in surface velocity and direction on unstable slopes in a periglacial environmentwith sporadic permafrost in northern Norway. By identifying areas with uplift and subsidence, and detecting velocity changes (downslope acceleration/deceleration) and related areas of extension and compression, we are able to explain driving and controlling mechanisms and geomorphology in two rockslides and one area with solifluction landforms

Recent Acceleration of a Rock Glacier Complex, Ádjet, Norway, Documented by 62 Years of Remote Sensing Observations

<p>The data contained in Adjet_Rock_Glacier_Data.zip are a part of a manuscript entitled “Recent Acceleration of a Rock Glacier Complex, Ádjet, Norway, Documented by 62 Years of Remote Sensing Observations” by Harald Øverli Eriksen, Line Rouyet, Tom Rune Lauknes, Ivar Berthling, Ketil Isaksen, Heidi Hindberg, Yngvar Larsen and Geoffrey D. Corner, submitted to the journal Geophysical Research Letters.</p><p><br></p><p><br></p><p>Adjet_Rock_Glacier_Data.zip includes several zip-files:</p><p><br></p><p>ArcGIS.zip contains an ESRI ArcMAP project, shapefiles of contour lines, and raster images of a DEM and two orthophotos covering the study area.</p><p><br></p><p>Area_Used_for_Comparison.zip containing a shapefile of area used for comparison of mean yearly velocity from offset-tracking data, TRI data and orthophoto comparison.</p><p><br></p><p>Climatic_Data.zip contains an excel with modelled gridded climatic data (daily air temperature, daily precipitation and snow depth).</p><p><br></p><p>Data_Used_For_Comparison_Fig2a_and_b.zip contains shapefiles and raster images used as source for Figure 2a and b.</p><p><br></p><p>Deformation_Data_extracted_from_Profile_AA_Fig2_Fig3.zipcontains excel-sheets with deformation data extracted from profile A–A’:</p><p>- 2D_Vectors_velocity_(length)_and_plunge_from_TSX_OT.csv containing 2D vector velocity and plunge of displacement from combined offset-tracking data from both TerraSAR-X ascending and descending geometries (2009–2014). Data are extracted using a 40 m buffer along profile A–A’.</p><p>- Deformation_Data_Clipped_from_Profile_AA.xlsx contains projections and calculations of velocity, strain rate, subsidence and uplift data used in Fig. 2 and Fig. 3.</p><p>- Extracted_Dem_and_Slope_Along_Profile_AA_10m_buffer.csv contains height and slope extracted from profile A–A’.</p><p><br></p><p><br></p><p>Deformation_Reference_Area.zipincludes the area used to reference InSAR and TRI displacement data.</p><p><br></p><p>Displacement_From_Orthophotos.zip with shapefiles giving displacement made by comparing position of boulders identified in orthophotos (1954–1977, 1977–2006 and 2006–2014).</p><p><br></p><p>Front_and_Scree_Apron_From_Orthophotos.zip with shapefiles of rock glacier fronts (1954, 1977, 2006, and 2014) and out limit of scree aprons (2006 and 2014) interpreted from orthophotos.</p><p><br></p><p><br></p><p>Instrumentation.zip contains shapefiles with position of in-situ instrumentation.</p><p><br></p><p>Profile_Line_AA.zip contains shapefile giving the extent of profile line A–A’.</p><p><br></p><p>Surface_Deformation_From_Glens_Flow_Law.zip containing an Excel-sheet with calculation of surface creep using Glen’s flow law.</p><p><br></p><p>Terrestrial_Radar_Interferometry.zip with raster datasets of accumulated displacement (TRI_deformation), calculated mean yearly displacement based on campaigns (TRI_mean_yearly_vel), and mean coherence for the 2014 and 2015 campaigns.</p><p><br></p><p>TSX_InSAR_Desc_Orbit.zip with a raster dataset based on 75 TerraSAR-X StripMap snow-free SAR scenes from descending geometry. </p><p><br></p><p>TSX_OT_Descending_Orbit_Proj_Into_Horiz_Plan_(m_per_year).zip with raster datasets giving the displacement of the rock glacier projected into the horizontal plane using offset-tracking data from TerraSAR-X scenes acquired in descending orbit. Based on scenes from the snow free seasons mean yearly displacements in meters are given (Offs_total_vector_lenght) for the years 2009, 2010, 2011, 2012, 2013, 2014 and 2016, and the total timespan 2009–2016. Datasets for the azimuth direction in degrees (Offs_tot_azimuth), north component (Offs_north) and west-east component (Offs_horiz), both in meter per year, of the displacement are also included.</p><div><br></div><p></p