Abstract
abundant field-data. This study highlights how overlying igneous rocks adversely affect imaging of underlying intrusions and rocks by decreasing seismic amplitude, frequency and making steeply dipping features near-impossible to image. Furthermore, seismic modelling in this study shows that, because of the high impedance contrast between siliciclastic host-rock
and dolerites, very thin (1-5 m) intrusions should in principle be imaged in reflection-seismic data at 3 km depth. However, comparison with actual seismic data with well-data shows significant amounts of unimaged sill intrusions, and this is likely due to limited seismic resolution, overburden complexity, inadequate velocity-models, and interference between reflections from closely spaced sills and sill-splays. Significant improvements to sill imaging and interpretation could be made by better predicting occurrence and geometry of sill intrusions and including these in velocity models.
| Original language | English |
|---|---|
| Pages (from-to) | 193-209 |
| Number of pages | 17 |
| Journal | Journal of the Geological Society |
| Volume | 175 |
| Issue number | 2 |
| Early online date | 1 Dec 2017 |
| DOIs | |
| Publication status | Published - Mar 2018 |
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Seismic interpretation of sill complexes in sedimentary basins : implications for the sub-sill imaging problem. / Eide, Christian Haug (Corresponding Author); Schofield, Nick; Lecomte, Isabelle; Buckley, Simon J. ; Howell, John A.
In: Journal of the Geological Society , Vol. 175, No. 2, 03.2018, p. 193-209.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Seismic interpretation of sill complexes in sedimentary basins
T2 - implications for the sub-sill imaging problem
AU - Eide, Christian Haug
AU - Schofield, Nick
AU - Lecomte, Isabelle
AU - Buckley, Simon J.
AU - Howell, John A
N1 - Acknowledgements: We thank reviewers Craig Magee and Murray Hoggett for considerate and insightful reviews that considerably improved this manuscript. The LIDAR data were acquired by Julien Vallet and Samuel Pitiot of Helimap Systems. We acknowledge NORSAR for an academic licence of the seismic modelling software SeisRoX, which was used to generate synthetic seismograms in this study, and NORSAR-2D, which was used for analysis of seismic propagation through the overburden models. The virtual outcrop was visualized and interpreted using LIME (http://virtualoutcrop.com/lime). We also acknowledge Tore Aadland for writing invaluable scripts used for import of the outcrop models to seismic modelling software, and Gijs A. Henstra and Björn Nyberg for assistance in the field. Funding: Funding for data acquisition was provided from the Research Council of Norway through the PETROMAKS project 193059 and the FORCE Safari project. Funding for data analysis and modelling was provided from PETROMAKS through the Trias North project (234152).
PY - 2018/3
Y1 - 2018/3
N2 - Application of 3D-seismic reflection-data to igneous systems in sedimentary basins has led to a revolution in the understanding of mafic sill complexes. However, there is considerable uncertainty on how geometries and architecture of sill-complexes within the subsurface relates to those imaged in seismic reflection-data. To provide constraints on how sill complexes in seismic data should be interpreted, we present synthetic seismograms generated from a seismic-scale (22x0.25 km) outcrop in East Greenland constrained byabundant field-data. This study highlights how overlying igneous rocks adversely affect imaging of underlying intrusions and rocks by decreasing seismic amplitude, frequency and making steeply dipping features near-impossible to image. Furthermore, seismic modelling in this study shows that, because of the high impedance contrast between siliciclastic host-rockand dolerites, very thin (1-5 m) intrusions should in principle be imaged in reflection-seismic data at 3 km depth. However, comparison with actual seismic data with well-data shows significant amounts of unimaged sill intrusions, and this is likely due to limited seismic resolution, overburden complexity, inadequate velocity-models, and interference between reflections from closely spaced sills and sill-splays. Significant improvements to sill imaging and interpretation could be made by better predicting occurrence and geometry of sill intrusions and including these in velocity models.
AB - Application of 3D-seismic reflection-data to igneous systems in sedimentary basins has led to a revolution in the understanding of mafic sill complexes. However, there is considerable uncertainty on how geometries and architecture of sill-complexes within the subsurface relates to those imaged in seismic reflection-data. To provide constraints on how sill complexes in seismic data should be interpreted, we present synthetic seismograms generated from a seismic-scale (22x0.25 km) outcrop in East Greenland constrained byabundant field-data. This study highlights how overlying igneous rocks adversely affect imaging of underlying intrusions and rocks by decreasing seismic amplitude, frequency and making steeply dipping features near-impossible to image. Furthermore, seismic modelling in this study shows that, because of the high impedance contrast between siliciclastic host-rockand dolerites, very thin (1-5 m) intrusions should in principle be imaged in reflection-seismic data at 3 km depth. However, comparison with actual seismic data with well-data shows significant amounts of unimaged sill intrusions, and this is likely due to limited seismic resolution, overburden complexity, inadequate velocity-models, and interference between reflections from closely spaced sills and sill-splays. Significant improvements to sill imaging and interpretation could be made by better predicting occurrence and geometry of sill intrusions and including these in velocity models.
U2 - 10.1144/jgs2017-096
DO - 10.1144/jgs2017-096
M3 - Article
VL - 175
SP - 193
EP - 209
JO - Journal of the Geological Society
JF - Journal of the Geological Society
SN - 0016-7649
IS - 2
ER -