Postglacial Fault Drilling Project (PFDP)

The proposed ICDP project 'Postglacial Fault Drilling Project' (PFDP) aims to investigate, via scientific drilling, the tectonic and structural characteristics of postglacial (PG) faults in northern Fennoscandia, including their hydrogeology and associated deep biosphere. Scientific advances in neotectonics, hydrogeology and deep biosphere studies are expected. Societal benefits include generating information relevant to nuclear waste disposal and exploitation of economic raw materials.

During the last stages of the Weichselian glaciation (ca. 9,000 - 15,000 years B.P.), reduced ice load and relaxation of accumulated tectonic stress resulted in rapid uplift in Fennoscandia. Active faulting occurred with fault scarps up to 150 km long and up to 30 m high. The faults are usually SE dipping, SW-NE oriented thrusts, and represent reactivated, pre-existing (probably up to Precambrian age) crustal discontinuities. PG faulting indicates that the glacio-isostatic compensation is not only a gradual viscoelastic phenomenon, but includes also unexpected violent tectonic events, e.g. - earthquakes of up to mag. 7-8 are estimated to result from PG faulting.

Some PG faults in Fennoscandia have been investigated extensively including structural tectonic investigations, geophysical surveys, reflection seismic studies and excavations, with only occasional shallow drilling (<100 m). Systematic in-situ information on PG faults at depth is lacking. The PFDP project aims to elucidate the following problems:

(1) What is the tectonic style, deep structure and depth extent of the PG faults?
(2) Are PG faults still active?
(3) What are the paleoseismic implications of postglacial faults?
(4) Did PG faults reactivate more than once? Is it possible to provide quantitative ages of the tectonic systems hosting PG faults?
(5) What are the present and paleostress fields of PG faults?
(6) How has the faulting affected the rock properties, structure and deformation in and near the fault surface?
(7) What are the hydraulic properties of PG faults, and how did they control fresh glacial meltwater recharge?
(8) What is the composition of groundwater (chemistry, salinity, pH, Eh, gas content) in PG faults?
(9) Is there a deep biosphere in PG faults?

See also:

• ICDP-10/09

Europe, Fennoscandia

68° 22' 04.50'' N, 24° 17' 28.35'' E (Please scroll down to end of page for more information.)

• workshop date not yet determined

• Ilmo Tapio Kukkonen, Geological Survey of Finland, Section of Geophysics, South Finland Unit
• Odleiv Olesen, Geological Survey of Norway, Geoscience Division, Continental Shelf Geophysics
• Maria V.S. Ask, Luleå University of Technology, Department of Civil, Mining and Environmental Engineering

Deep Biosphere , Europe , Faults , Fennoscandia , Finland , Hydrogeology , ICDP-10/09 , Lappland , Norway , PFDP , Postglacial , Stress Field , Sweden

Workshop in preparation

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