Abstract
The processes and the structures within the middle and the lower crust are intimately related to the evolution of orogenies, but more detailed knowledge is needed of these deep crustal processes. Seismic reflection data, chiefly displayed in amplitude, are commonly used to interpret deep crustal structures. The strongest amplitude events are probably related to lithological changes and do not necessarily correspond to geological structures, tectonic boundaries, or deformation fabrics. Furthermore, the detailed structures and the strain distribution between the interpreted structural boundaries remain obscure. Here, we show an example of how seismic attributes, combined with the seismic facies interpretation technique, can be used to enhance 2D seismic reflection data from the Palaeoproterozoic Svecofennian crust of southern Finland,
to reveal unprecedentedly detailed information about the deformation fabrics within the mid-crust of a collisional orogen. The images are plausibly interpreted to show that the extension/lateral flow of the orogenic
middle and lower crust was mainly accommodated by kilometer-scale S-C0 structures. The structures form penetrative deformation fabrics which are correlated with outcrop observations. The successful enhancement of the seismic data confirms the ductile extension affecting hot orogenic crust, and gives new information about the strain distribution of the regional, syn- to late-orogenic deformation. The seismic attribute method and the seismic facies interpretational approach described in this paper should be applicable to other seismic datasets from the crystalline basement.
to reveal unprecedentedly detailed information about the deformation fabrics within the mid-crust of a collisional orogen. The images are plausibly interpreted to show that the extension/lateral flow of the orogenic
middle and lower crust was mainly accommodated by kilometer-scale S-C0 structures. The structures form penetrative deformation fabrics which are correlated with outcrop observations. The successful enhancement of the seismic data confirms the ductile extension affecting hot orogenic crust, and gives new information about the strain distribution of the regional, syn- to late-orogenic deformation. The seismic attribute method and the seismic facies interpretational approach described in this paper should be applicable to other seismic datasets from the crystalline basement.
| Original language | English |
|---|---|
| Pages (from-to) | 1069-1086 |
| Number of pages | 18 |
| Journal | Geochemistry, Geophysics, Geosystems |
| Volume | 14 |
| Issue number | 4 |
| Early online date | 29 Apr 2013 |
| DOIs | |
| Publication status | Published - Apr 2013 |
Bibliographical note
We are grateful to senior editor Thorsten Becker, Djordje Grujic, and Dan Tatham for their constructive comments and reviews. Richard England and Richard Hobbs are sincerely thanked for their helpful comments to an earlier version of the article. We would also like to acknowledge the team of dGB Earth Sciences for the full OpendTect academic license. We are especially grateful to Arnaud Huck of dGB for his help during the method testing. Enthought Scientific Solution is thanked for their Python distribution. Nina Heikkinen, Lars Kaislaniemi, and Helena Susi are a thanked for field assistance. The field work was financed by K.H. Renlunds Stiftelse. T.T. was partly supported by the Virtual Seismic Atlas project (www.seismicatlas.org), where the high-resolution seismic images can be downloaded.Keywords
- Seismic reflection data
- Seismic attributes
- Seismic interpretation
- Orogeny
- Mid-crustal flow