Geology Reference
In-Depth Information
SEA
LAND
A
E
C
F
F
F
E
Tidal
maximum
E
E
D
B
F
F
F
F
E
E
E
Tidal modulation of current speeds
Current reversals
Tidal dominance
River dominance
Fig. 3.28
Schematic diagram showing various relationships between fl uvial discharge and tidal fl ux in an estuary as tidal infl uence is
modulated. This diagram may cover only a kilometer or so, or it may extend for many tens of kilometers (From Dalrymple and Choi
2007
)
conditions. An excellent example of this is present in
tidal fl ats of the German Wadden Sea (Davis and
Flemming
1995
; see Chap. 10 ). Here extensive tidal
fl at accumulations lack tidal signatures but the sedi-
ments in and adjacent to the tidal channels show good
tidalite signatures.
sediments. What we see as tidalites in the stratigraphic
record may represent the minimum of preserved tid-
ally-infl uenced environments.
References
3.5
Summary
Adkins RM, Eriksson KA (1998) Rhythmic sedimentation in a
mid-Pennsylvanian delta-front succession, Magoffi n Member
(Four Corners Formation, Breathitt Group), eastern
Kentucky: a near-complete record of daily, semi-monthly,
and monthly tidal periodicities. In: Alexander CR, Davis
RA, Henry VJ (eds.) Tidalites: processes and products,
SEPM special publication 61. SEPM Society for Sedimentary
Geology, Tulsa, pp 85-94
Allen GP, Posamentier HW (1994) Transgressive facies and
sequences architecture in mixed tie- and wave-dominated
incised valleys: examples from the Gironde estuary, France.
In: Dalrymple RW, Zaitlin BA, Boyd R (eds.) Incised valley
systems: origin and sedimentary sequences. SEPM special
publication 51. SEPM Society for Sedimentary Geology,
Tulsa, pp 225-240
Archer AW (1998) Hierarchy of controls on cyclic rhythmite
deposition, Carboniferous basins of eastern and mid-
continental USA. In: Alexander CR, Davis RA, Henry VJ
(eds.) Tidalites: processes and products, SEPM special pub-
lication 61. SEPM Society for Sedimentary Geology, Tulsa,
pp 59-68
Boggs SN (2001) Principles of sedimentology and stratigraphy,
3rd edn. Prentice-Hall, Englewood Cliffs
Collinson JD (1968) Deltaic sedimentation in the Upper
Carboniferous of northern England. Sedimentology 10:223-254
Tidalites accumulate in a wide range of depositional
environments. In nearly all cases they represent con-
ditions where tidal fl ux transported sediment that
accumulated incorporating the typical tidal signature
of heterolithic bedding of some type, usually in the
form of tidal bedding or tidal bundles. Scale may
range widely, especially in tidal bundles. Monolithic
tidalites occur but are not common. It is likely that
tidal deposits in monolithic depositional environ-
ments commonly do not leave tidal signatures and are
therefore, not recognized in the stratigraphic record.
Exceptions include the Precambrian Baraboo and the
Cambrian Jordan sandstones of Wisconsin (Pape
et al.
2003
) where tidalites comprised entirely of
well-sorted sand occur. Waves and bioturbation can
destroy tidal signatures and commonly do so.
Extensive environments occur where tidal fl ux is
present but without enough energy to transport
