Journal cover Journal topic
Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Model description paper
13 Jul 2017
Review status
This discussion paper is a preprint. A revision of this manuscript was accepted for the journal Geoscientific Model Development (GMD) and is expected to appear here in due course.
SILLi 1.0: A 1D Numerical Tool Quantifying the Thermal Effects of Sill Intrusions
Karthik Iyer1,2, Henrik Svensen3, and Daniel W. Schmid1,4 1GeoModelling Solutions GmbH, Zurich, Switzerland
2GEOMAR, Helmholtz Centre for Ocean Research, Kiel, Germany
3Centre for Earth Evolution and Dynamics, University of Oslo, Norway
4Physics of Geological Processes, University of Oslo, Norway
Abstract. Igneous intrusions in sedimentary basins may have a profound effect on the thermal structure and physical properties of the hosting sedimentary rocks. These include mechanical effects such as deformation and uplift of sedimentary layers, generation of overpressure, mineral reactions and porosity evolution, and fracturing and vent formation following devolatilization reactions and the generation of CO2 and CH4. The gas generation and subsequent migration and venting may have contributed to several of the past climatic changes such as the end-Permian event and the Paleocene-Eocene Thermal Maximum. Additionally, the generation and expulsion of hydrocarbons and cracking of pre-existing oil reservoirs around a hot magmatic intrusion is of significant interest to the energy industry. In this paper, we present a user-friendly 1D FEM based tool, SILLi, which calculates the thermal effects of sill intrusions on the enclosing sedimentary stratigraphy. The model is accompanied by three case studies of sills emplaced in two different sedimentary basins, the Karoo Basin in South Africa and the Vøring Basin offshore Norway. Input data for the model is the present-day well log or sedimentary column with an Excel input file and includes rock parameters such as thermal conductivity, total organic carbon (TOC) content, porosity, and latent heats. The model accounts for sedimentation and burial based on a rate calculated by the sedimentary layer thickness and age. Erosion of the sedimentary column is also included to account for realistic basin evolution. Multiple sills can be emplaced within the system with varying ages. The emplacement of a sill occurs instantaneously. The model can be applied to volcanic sedimentary basins occurring globally. The model output includes the thermal evolution of the sedimentary column through time, and the changes that take place following sill emplacement such as TOC changes, thermal maturity, and the amount of organic and carbonate-derived CO2. The TOC and vitrinite results can be readily benchmarked within the tool to present-day values measured within the sedimentary column. This allows the user to determine the conditions required to obtain results that match observables and leads to a better understanding of metamorphic processes in sedimentary basins.

Citation: Iyer, K., Svensen, H., and Schmid, D. W.: SILLi 1.0: A 1D Numerical Tool Quantifying the Thermal Effects of Sill Intrusions, Geosci. Model Dev. Discuss.,, in review, 2017.
Karthik Iyer et al.
Interactive discussionStatus: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version      Supplement - Supplement
RC1: 'The suggested revisions', Anonymous Referee #1, 04 Sep 2017 Printer-friendly Version 
AC1: 'Author's reply to Reviewer#1', Karthik Iyer, 24 Oct 2017 Printer-friendly Version 
RC2: 'Iyer et al: SILLi Revisions.', Anonymous Referee #2, 10 Oct 2017 Printer-friendly Version 
AC2: 'Author's reply to Reviewer#2', Karthik Iyer, 24 Oct 2017 Printer-friendly Version 
Karthik Iyer et al.
Karthik Iyer et al.


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