**6. Concluding Remarks**

This study quantified the porosity loss due to the transition of opal A to opal CT to quartz, smectite to illite and quartz diagenesis and how magmatic intrusions may a ffect the diagenetic process. As the diagenetic alterations change the physical properties of the rock, it was shown how these alterations and the sills themselves influence location of stress accumulations in a basin and thus may contribute to changes in fracture and fault permeability. All these factors have implications for the petroleum system and the results are summarized as follows:


**Author Contributions:** Conceptualization, M.S., W.F., I.G. and I.F.L.; methodology, M.S., W.F. and I.G.; software, M.S., W.F. and I.G.; formal analysis, M.S. and I.G.; investigation, M.S.; writing—original draft preparation, M.S.; writing—review and editing, W.F., I.G., I.F.L. and R.M.; visualization, M.S.; supervision, W.F. and R.M.; project administration, I.F.L.; funding acquisition, I.F.L.

**Funding:** This research was partly funded by The Research Council of Norway and Tectonor AS as a part of the PhD project 'E ffects of magmatic intrusions on temperature history and diagenesis in sedimentary basins—and the impact on petroleum systems', RCN project number 257492.

**Acknowledgments:** We want to express gratitude for the support received. Inspiring conversations with Professors Olav Eldholm and Elen Roaldset, and valuable discussions with Professor Leiv K. Sydnes are highly appreciated. Two anonymous reviewers and Academic Editor are thanked for constructive and helpful comments that improved the contents and design of the paper.

**Conflicts of Interest:** The authors declare no conflict of interest.
