Field trip - Jæren – from Precambrium to Quaternary, from onshore geology to offshore implications. A two day work shop in the field
The field trip is a cooperation between FORCE and the University of Stavanger. The first day focus on the Precambrian to post Caledonian geology of Jæren. One focus will be on the on-shore off-shore relationship between Jæren and the North Sea. The second day is devoted to group work addressing the deposition of reservoir sandstone on basement.
Field trip to Jæren
Day 1 - Rennesøy and Fjøløy (Field Guide Alexander Lassen)
We will cover some aspects of the Jæren geology – mainly the Caledonian orogenic history of the area and what happened afterwards - as it can be pieced together today. We will also discuss the relationship between the Jæren on-shore geology and the off-shore structures observed in the adjacent southern North Sea basin. The post Caledonian history is not directly present in the Rennesøy area in the shape of sediments – only glacial/fluvial deposits remain. However, the Caledonian cover is dissected by several fracture systems that bear witness to numerous changes in the regional stress field since the end of the Caledonian compression. We will visit the islands of Rennesøy (stop 1) and Fjøløy (stop 2) northwest of Stavanger to look at the structure and mineralogy of the upper part of the Boknfjorden trust sheet or nappe complex as termed by Birkeland, 1981. From Helland on Rennesøy the “strand flat” coastal morphology is particularly evident, and we will briefly discuss mechanisms for its emplacement. On Fjøløy we will look at the geology of the middle to lower part of the Boknfjorden thrust sheet and the fracture sets that can tell us something about post Caledonian tectonic events that affected the area. Finally we will enjoy the “360” view from the top of Fjøløy Fort which gives a nice regional summary view of north Jæren, the islands north and west of Jæren, the Precambrian basement provinces to the East and the uppermost Caledonian trust sheet to the west.
Day 2 – Seland Sandpit (Group work and discussions)
Sedimentary architecture from the scale of laminae to overall valley-fill geometry can be studied in the Seland sand pit. A glacially eroded valley is filled with glaciodeltaic sand which has later been incised during post glacial rebound. The combination of 2D georadar profiles and 3D outcrop makes this location an excellent laboratory for the study of reservoir sandstones accommodated in a basement valley. The field trip participants will work in small groups guided by sedimentologists (in outcrop) and geophysisicsts (for subsurface data analysis). The groups will gather data, acquire one new georadar line each and meet up in the end to discuss results.
The organizing committee will be ‘active participants’ who lead the groups, provide data and give you the necessary background information before the group work starts.
There will be bus transportation with departure from Stavanger in the morning and return between 4 and 5 pm both days. More information will be provided prior to the trip.
Force member/non-member/student NOK 1500,-
Maximum number of participants are 25.
Please note, there is no reduced member/student fee on this field trip.
Registration at the top right.
Professor Alejandro Escalona (University of Stavanger)
Associate Professor Wiktor Weibull (University of Stavanger)
Maria Rodriguez (University of Stavanger)
Alexander Lassen (ConocoPhillips)
Bjørn Kåre Bryn (Spirit)
Rikke Bruhn (Capricorn)
Torben Olsen (KUFPEC)
Eirik R. Knudsen (AkerBP)
Tone Helene Mydland (NPD)