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and summer wet conditions along the northern
Tethyan margin (Manzpeizer, 1982; Kutzbach &
Gallimore, 1989; Parrish, 1993; Sellwood & Valdes,
2006, 2007). Episodic marine flooding of the
Southern Permian Basin in the Middle Triassic may
have buffered the local climate and elevated humid-
ity levels in the central North Sea (McKie & Williams,
2009). In order to assess the relative impact of cli-
matic changes on the Skagerrak Formation fluvial
systems it is important to identify whether any
apparent change in fluvial depositional character
within the central North Sea was a product of a
regional climatic change within the basin, changes
originating in the catchments, or a response to more
local factors, e.g. fluvial avulsions creating locally
wet conditions within an otherwise arid basin (c.f.
van der Zwan & Spaak, 1992; Visscher
et al
., 1994).
Regional facies associations provide a general sense
of basinal climate at a broad scale across the region
(Bourquin
et al
., 2009), which can be combined with
palynology and a range of climate proxies to develop
a regional framework of the evolving climatic situa-
tion across north-west Europe.
mud-prone playa and evaporites and show limited
evidence of significant standing water (Ruffell &
Shelton, 1999; McKie & Williams, 2009). Exceptions
to this pattern of general aridity occurred in the
Middle Carnian, Late Ladinian and possibly Late
Norian, with the brief development of more peren-
nial lacustrine conditions (Milroy & Wright, 2000;
Porter & Gallois, 2008) during wetter climatic
episodes. However, evidence of aeolian activity,
evaporite precipitation and desiccated playa can be
traced as far north as eastern Greenland until the
Carnian (Surlyk, 1990). The general impression
from these regions is one of an arid continental
interior, with any significant fluvial input derived
from distant, wetter catchments or during discrete
pluvial events of regional to global significance.
The evidence of aridity, based on the dryland
facies within the continental interior is supported
by general circulation models which show the
region as one of net evaporation (Kutzbach &
Gallimore, 1989; Parrish, 1993; Péron
et al
., 2005).
These models also suggest that the central North
Sea region itself was probably relatively arid. This
aridity is broadly indicated by the downstream
shale-out of the Skagerrak Formation fluvial sys-
tems, indicating that flood waters were entirely
dissipated through evaporation and transmission
losses, resulting in terminal, endorheic fluvial sys-
tems. However, despite these arid conditions there
is little evidence in the central North Sea of sig-
nificant evaporite precipitation beyond isolated
instances of salt crust fabrics and no evidence of
significant aeolian reworking after the Early Triassic.
Anhydrite is present within the Middle Triassic
Julius Mudstone in the southern part of the central
North Sea (Goldsmith
et al
., 1995; Michelsen &
Clausen, 2002), which may reflect the development
of coastal sabkha facies on the northern margin of
the Muschelkalk Sea, but the overall prevalence of
plant rooting and burrows is more indicative of an
availability of year-round soil moisture, suggesting
that runoff from the catchments was perennial
(albeit seasonal) and that groundwater was deliv-
ered into the central North Sea, even during dry sea-
sons, to suppress evaporitic and aeolian processes
and maintain biogenic activity.
An arid rift interior
To the west of the North Sea region, in basins that
were remote from Tethyan and Muschelkalk
marine influence and located within the heart of
the rift system, the Triassic succession is charac-
terised by widespread evidence of sustained arid-
ity. Brookfield (2004, 2008) documents a Triassic
succession within the Solway Basin (Fig. 1), par-
tially isolated from the main rift axes, which was
deposited under consistently arid to hyper-arid
conditions with little evidence of dramatic climate
oscillations. Supply of sand into the basin did not
occur via large river systems and was likely to
have been dominated by aeolian transportation
and subsequent reworking by small desert streams
generated by local rainstorms. Outside of this iso-
lated basin large Early Triassic fluvial systems
flowed northwards through the UK and offshore
Ireland, but these were largely sourced from remote,
wetter catchments and terminated within these
arid interior basins (cf Péron
et al
., 2005). The
terminal regions of these systems (e.g. East Irish
Sea) lack evidence of significant vegetation and
were subject to widespread aeolian reworking
in evaporite-prone, terminal basins (McKie &
Williams, 2009). The Middle and Late Triassic fills
of these interior basins show very little evidence
of fluvial activity and are largely composed of
Skagerrak Formation fluvial expansion
during pluvial phases
Whilst the latitudinal position of north-west
Europe within Pangaea dictated a generally arid
climatic regime, fluctuations in aridity are recorded
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