Challenges in geophysical mapping of glaciotectonic structures

ABSTRACTGlaciotectonic complexes have been recognized worldwide — traditionally described on the basis of outcrops or geomorphological observations. In the past few decades, geophysics has become an integral part of geologic mapping, which enables the mapping of buried glaciotectonic complexes. The geophysical methods provide different types of information and degrees of resolution and thus, a different ability to resolve the glaciotectonic structures. We evaluated these abilities on the basis of an integrated application of four commonly used geophysical methods: airborne transient electromagnetics, high-resolution reflection seismic, geoelectrical, and ground-penetrating radar (GPR). We covered an area of 100  km2 in a formerly glaciated region in the western part of Denmark. The geologic setting was highly heterogeneous with glaciotectonic deformation observed in the form of large-scale structures in the seismic and airborne transient electromagnetic data to small-scale structures seen in the GPR and g...

[1]  Esben Auken,et al.  The application of the transient electromagnetic method in hydrogeophysical surveys , 2003 .

[2]  Harry M. Jol,et al.  Ground penetrating radar antennae frequencies and transmitter powers compared for penetration depth, resolution and reflection continuity1 , 1995 .

[3]  R. A. Overmeeren,et al.  Continuous vertical electrical sounding , 1988 .

[4]  M. Bakker,et al.  Structure of a Pleistocene push moraine revealed by GPR: the eastern Veluwe Ridge, The Netherlands , 2003, Geological Society, London, Special Publications.

[5]  Esben Auken,et al.  SkyTEM–a New High-resolution Helicopter Transient Electromagnetic System , 2004 .

[6]  P. Jakobsen,et al.  Georadar facies and glaciotectonic structures in ice marginal deposits, northwest Zealand, Denmark , 2002 .

[7]  T. Dahlin,et al.  A comparison of the Gauss-Newton and quasi-Newton methods in resistivity imaging inversion , 2002 .

[8]  H. Christiansen,et al.  Structure and composition of a tidewater glacier push moraine, Svalbard, revealed by DC resistivity profiling , 2009 .

[9]  S. Pedersen Structural analysis of the rubjerg Knude Glaciotectonic Complex, Vendsyssel, northern Denmark , 2005 .

[10]  A. Christiansen,et al.  A global measure for depth of investigation , 2012 .

[11]  T. Dahlin,et al.  Resolution of 2D Wenner resistivity imaging as assessed by numerical modelling , 1998 .

[12]  Andreas Kemna,et al.  Complex resistivity tomography for environmental applications , 2000 .

[13]  T. Dahlin,et al.  Multiple-gradient array measurements for multichannel 2D resistivity imaging , 2006 .

[14]  A. Pugin,et al.  First-Arrival Alignment Static Corrections Applied to Shallow Seismic Reflection Data1 , 2000 .

[15]  A. Neal Ground-penetrating radar and its use in sedimentology: principles, problems and progress , 2004 .

[16]  K. Sørensen Pulled Array Continuous Electrical Profiling , 1996 .

[17]  A. Christiansen,et al.  Resolving spectral information from time domain induced polarization data through 2-D inversion , 2013 .

[18]  Venkat Lakshmi,et al.  Advancing process‐based watershed hydrological research using near‐surface geophysics: a vision for, and review of, electrical and magnetic geophysical methods , 2008 .

[19]  Esben Auken,et al.  Geophysical investigations of buried Quaternary valleys in Denmark: an integrated application of transient electromagnetic soundings, reflection seismic surveys and exploratory drillings , 2003 .

[20]  M. Huuse,et al.  Large-scale glaciotectonic thrust structures in the eastern Danish North Sea , 2000, Geological Society, London, Special Publications.

[21]  E. Auken,et al.  Contributions to the geological mapping of Mors, Denmark - A study based on a large-scale TEM survey , 2005 .

[22]  K. Sørensen,et al.  Pulled array continuous electrical sounding with an additional inductive source: an experimental design study , 2001 .

[23]  J. S. Aber,et al.  Glaciotectonic Structures in Central Sweden and their Significance for Glacial Theory , 2007 .

[24]  D. Oldenburg,et al.  Inversion of induced polarization data , 1994 .

[25]  S. Szalai,et al.  Which geoelectric array sees the deepest in a noisy environment? Depth of detectability values of multielectrode systems for various two-dimensional models , 2011 .

[26]  Esben Auken,et al.  Combined interpretation of SkyTEM and high-resolution seismic data , 2011 .

[27]  Alan G. Green,et al.  Design and application of a towed land‐streamer system for cost‐effective 2-D and pseudo-3-D shallow seismic data acquisition , 2001 .

[28]  Jonathan R. Lee,et al.  Glacitectonics : field guide , 2011 .

[29]  H. Mooers Ice-marginal thrusting of drift and bedrock: thermal regime, subglacial aquifers, and glacial surges , 1990 .

[30]  I. Møller,et al.  Testing ground-penetrating radar for resolving facies architecture changes - a radar stratigraphic and sedimentological analysis along a 30 km profile on the Karup Outwash Plain, Denmark , 2006 .

[31]  Esben Auken,et al.  Piecewise 1D laterally constrained inversion of resistivity data , 2005 .

[32]  D. V. D. Wateren A model of glacial tectonics, applied to the ice­pushed ridges in the Central Netherlands , 1985, Bulletin of the Geological Society of Denmark.

[33]  Richard D. Miller NORMAL MOVEOUT STRETCH MUTE ON SHALLOW-REFLECTION DATA , 1992 .

[34]  T. Dahlin,et al.  A numerical comparison of 2D resistivity imaging with 10 electrode arrays , 2004 .

[35]  J. Merritt,et al.  Quaternary deformation mapping with ground penetrating radar , 1999 .

[36]  A. Christiansen,et al.  An integrated processing scheme for high-resolution airborne electromagnetic surveys, the SkyTEM system , 2009 .

[37]  W. Kupsch Ice-Thrust Ridges in Western Canada , 1962, The Journal of Geology.

[38]  A. Christiansen,et al.  Quasi-3D modeling of airborne TEM data by spatially constrained inversion , 2008 .

[39]  D. Sharpe,et al.  Seismic facies and regional architecture of the Oak Ridges Moraine area, southern Ontario , 1999 .

[40]  Esben Auken,et al.  Transboundary geophysical mapping of geological elements and salinity distribution critical for the assessment of future sea water intrusion in response to sea level rise , 2012 .

[41]  Flemming Jørgensen,et al.  Buried and open tunnel valleys in Denmark—erosion beneath multiple ice sheets , 2006 .

[42]  P. Gibbard,et al.  Large‐scale glaciotectonic deformation in the Great Lakes basin, USA‐Canada , 2003 .

[43]  A. V. Loon,et al.  Inventory of deformational structures as a tool for unravelling the Quaternary geology of glaciated areas , 2008 .

[44]  M. Dabas,et al.  A novel mobile multipole system (MUCEP) for shallow (0–3 m) geoelectrical investigation: the ‘Vol‐de‐canards’ array , 1997 .

[45]  Harry M. Jol,et al.  GPR in sediments: advice on data collection, basic processing and interpretation, a good practice guide , 2003, Geological Society, London, Special Publications.

[46]  Öz Yilmaz,et al.  Seismic data processing , 1987 .

[47]  J. S. Aber Kineto-stratigraphy at Hvideklint, M0n, Denmark and its regional significance , 1980, Bulletin of the Geological Society of Denmark.

[48]  B. Pjetursson,et al.  Free, online Danish shallow geological data , 1969 .

[49]  T. Dahlin 2D resistivity surveying for environmental and engineering applications , 1996 .