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The four flooding surfaces in the TDDP element are
interpreted as local features due to their laterally
restricted extent, thin overlying shale beds and
presence of marine palynomorphs. The surfaces
are thought to reflect rapid local changes in relative
sea-level in a tide-dominated deltaic depositional
system that included several minor distributaries
along a highly sinuous coastline. Although similar
flooding surfaces in the northern area cannot be
physically traced from one locality to the next,
these may correspond to those in the southern area.
Allostratigraphic unit 2, overlying FSa in the
southern area and MFS1 in the northern area, is
interpreted to show an overall progradational to
aggradational depositional style. Partly based on the
more terrestrial signature of its palynomorph con-
tent, the northern area is interpreted to represent a
more proximal deltaic depositional setting than cor-
responding deltaic architectural elements in the
southern area. The progradational to aggradational
depositional trend determined from the organisation
of architectural elements reflects continuously
higher rates of sediment input compared to the rate
of creation of accommodation space (A < S). Laterally
shifting channel infill facies associations and
inclined heterolithic strata facies associations
accompanied by the most proximal facies in the
upper part of the TDDP element are interpreted as
the most proximal deltaic deposits within allostrati-
graphic unit 2. The TDSS element recorded in the
southern area represents deeper water deposits than
the underlying TDDP element and indicates a land-
ward shift in facies and thus a turnaround towards a
rise in relative sea-level. The TDSS element is topped
by the transgressive surface TS2 that defines the
drowning of the distal tide-dominated deltaic depo-
sitional system in the southern area. In the northern
area the uppermost delta platform deposits are
eroded by the combined SU1/TS3 surface (Fig. 7).
(Koppelhus & Dam, 2003). The top of allostrati-
graphic unit 3 is well defined by a sharp facies
boundary with occasional rounded quartz pebbles
along the base of overlying sandstones (Fig. 5B). The
bounding surfaces amalgamate and allostratigraphic
unit 3 pinches out north of locality S6 (Fig. 7).
The base of allostratigraphic unit 3 consists of
an up to 2 m thick, fine-grained structureless or
weakly cross-stratified sandstone bed. This bed
passes northwards into multiple thinner, strongly
bioturbated (
Diplocraterion parallelum
) and
poorly sorted gravelly and pebbly beds (Figs 7 and
9B). Several hummocky-stratified sandstone beds,
as well as hundreds of metres wide and few deci-
metres thick matrix-supported conglomeratic
beds composed of well-rounded quartz and
quartzite pebbles and elongated cobbles (<6 cm in
diameter) are observed within the muddy-hetero-
lithic lower 10 m of the allostratigraphic unit 3
(Fig. 9A and B). The matrix in the conglomeratic
beds is the same silty mudstone to fine-grained
sandstone as below and above these beds. The bed
contacts are sharp, but no clear concave or convex
lateral shape has been recorded. The upper half of
allostratigraphic unit 3 is better sorted and more
sand-rich and shows a slight upward-coarsening
trend. Allostratigraphic unit 3 is also distorted by
up to 15 m thick horizontal dolerite sills (Fig. 3)
and thinner vertical dykes of Palaeogene age (c.f.
Larsen & Marcussen, 1992).
Interpretation: Allostratigraphic unit 3
The basal surface of allostratigraphic unit 3 is
interpreted as a marine transgressive ravinement
surface (TS2) representing a shift from aggrada-
tional to retrogradational depositional trend. The
mudstone-dominated facies associations in the
allostratigraphic unit 3 are interpreted to compose
the wave-dominated brackish-marine embayment
(WDBE) architectural element (Fig. 9A and B;
Table 3). The northward increase in abundance of
coarse-grained beds in the lowermost part of the
allostratigraphic unit 3 may be due coastal insta-
bilities and along-strike facies variation in a north-
ward shallowing depositional environment. The
mudstone-dominated sediments that comprise the
lower half of allostratigraphic unit 3 are interpreted
to have accumulated in a retrograding prodelta
depositional environments. The several laterally
restricted pebbly debris flow beds and associated
tempestite sandstone beds within the lower half
of the allostratigraphic unit 3 are interpreted as
storm induced deposits (cf. Dam & Surlyk, 1998)
Allostratigraphic unit 3
Description: Retrogradational to progradational
architectural elements
The muddy heterolithic allostratigraphic unit 3 is
up to 26 m thick and restricted to the southern area
where it overlies the transgressive surface TS2
(Fig. 7). Allostratigraphic unit 3 is composed of
offshore marine mudstone (FA7b) and wave-
dominated brackish-marine embayment mudstone
and siltstone (FA6a) facies associations (Fig. 9A and
B; Table 2). Brackish and marine palynomorphs
have been recorded in allostratigraphic unit 3
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