Fróðskaparrit - 01.01.2005, Síða 143
News and progress 2004
Nýtt innan vísindi 2004
Fríðbjørg Biskopstøð
Cenozoic structural and stratigraphic development of the Faroe-Shetland Basin and
Faroe Graben
Ph.D.-thesis at the University of Edinburgh, Dep. of Geology and Geophysics, 13
December 2004.
Seismic stratigraphic analyses of the late
Palaeocene-Present transitional to post-rift
succession in the Faroe-Shetland Basin
and Faroe Graben (FSC) on the NE At-
lantic volcanic passive continental rnargin
have revealed the occurrence of an Early
Eocene dendritic palaeo-drainage system
and Middle Eocene-Miocene contractional
inversion structures.
The palaeo-drainage system consists of
a significant NNW-SSE trending distribu-
tary channel (40km long, 5km wide and
up to 400m deep), fed by numerous tribu-
taries (lOOm deep). The drainage system
incised into a major delta system (Colsay
Sandstone Member) and was subsequently
infilled and draped by estuarine deposits
(Hildasay Sandstone Member and Balder
Formation). The excellent preservation
of the palaeo-valleys indicates that up-
lift, incision and subsequent infilling of
the drainage system occurred relatively
rapid (biostratigraphically constrained to
ca. 1 My). The uplifting responsible for
the incision event (at c. 54.7 Ma, earliest
Ypresian) was widespread and extends as
far as the North Sea (Bressay area) and SE
England (London Basin). Furthermore,
coeval volcanic activity is consistent with
the drainage system having resulted from
transient uplift driven by a mantle-plume.
This transient uplift event (incision and
infill) in the FSC provides important new
evidence for the evolution of the ancestral
Iceland mantle plume and its influence on
stratigraphic development.
The inversion structures, developed in
Middle Eocene, Oligocene and Middle
Miocene, are marked by folding with the
syn/post inversion stratigraphy onlapping
and thinning over the structures. The loca-
tion and orientation of the inversion struc-
tures suggest that the underlying Mesozoic
structural configuration, especially the
NW-SE transfer zones, influenced their
development. Temporal and spatial rela-
tionships between the inversion structures
in the FSC and similar structures identi-
fied along the length of the NW Atlantic
margin suggest that a complex interac-
tion of different forces (related to plate-
reorganizations and plume activity) acted
in concert and are responsible for their
generic development. The timing and na-
Fróðskaparrit 53. bók 2005; 141-154