EVAPORITE
STRATIGRAPHIC SIGNALS
OF BASE LEVEL CHANGE
IN THE GEOLOGIC RECORD
Christopher G. St. C. Kendall
Geological Sciences,
Univ of South Carolina, Columbia, SC
kendall@sc.edu
PRESENTATION OUTLINE
Interpretation of stratigraphic sections is often
based on the use of surfaces to subdivide the
section – namely “Sequence Stratigraphy”
If constrained by time & depositional setting the
bounding surfaces of evaporites form distinct &
widespread stratigraphic markers
 Updip
supratidal sabkha evaporite cycles
 Downdip restricted playas & basin evaporites
Unique & strong ties exist and constrain the
timing of the accumulation linear belts of marine
& lacustrian evaporites when arid climates &
plate tectonic setting coincide
Sequence Stratigraphic
Interpretation
The subdivision of sedimentary section by time
significant & widespread surfaces that record
sharp changes in sedimentary character, erosion
and/or non-deposition e.g.:
Maximum flooding surfaces (time of maximum
transgression)
Transgressive surfaces (first significant flooding
surface of a sequence)
Sequence boundaries (significant erosional
unconformiy produced by fall in sea level)
Bounding Surfaces of Evaporites
Distinct & widespread stratigraphic markers
constrained by time & depositional setting:
Updip supratidal sabkha evaporite cycles
(upper bounding surface preserved in
regressive coastlines matching sea level
position of the late high stand system tract)
Downdip restricted playas & basin
evaporites (upper surface coincides with
sea level position of the lowstand and
following transgressive system tract)
Updip Supratidal Sabkha Cycles
Regressive coastlines match the sea level
position of the late Highstand SystemTract
Matrix rich
Circumscribe depositional basin
Interbedded facies include:Up dip - Wadii sediments & aeolian sand
Down dip - Cycles of shallow water carbonate
Evaporites – sometimes signaled by solution
breccias
Examples: Modern of UAE
Ancient of Permian Basin
52oE
54oE
56oE
I R A N
N
MASANDAM
PENINSULA
Wind direction of
“Shamal”
26oN
Ras Al
Khaimah
GULF OF
OMAN
Fujairah
Dubai
QATAR
Ras
Ghanada
Jabal
Odaid
ABU
DHABI
Jabal Dhanna
Al Ain
24oN
OMAN
Central Coast
SAUDI
ARABIA
Western Coast
UNITED ARAB EMIRATES
50 km
Major coastal provinces of the United Arab Emirates and the bathymetry of the Southern
Arabian Gulf in fathoms (modified from Purser, 1973).
Western Coast of the United Arab Emirates
Western Coastal Margin of the United Arab Emirates
High Intertidal
Cyanobacterial
Flats
Earlier High
Energy Beaches
Supratidal
Sabkha
Evaporites
Intertidal
Carbonate
Flats
Ptygmatic
Anhydrite
& Storm Washover
Upper Intertidal
Cyanobacteria
Mats
Diapiric
Anhydrite
After Gypsum
Deflation
Surface of
Aeolian
Carbonate
Sabkha
Sediments
Basin
Margin
Carbonates
Upper Tidal
Flat Dolomite
Sabkha of the “Guadalupian”
Permian Seven Rivers Formation,
of the Seven Rivers Embayment,
New Mexico.
Supratidal
Gypsum
Windblown
& Fluvial Silts
Collapse Breccia in the Seven
Rivers Formation Dark Canyon,
New Mexico.
Upper
Tidal Flat
Dolomites
Collapse
after
Evaporites
Upper
tidal flat
dolomites
Basinal
evaporites
Restricted Playas & Basin
Evaporites
Match sea level of Lowstand and
Transgressive System Tract
Matrix poor
Deeper parts of the isolated evaporite
basin
Extensive bodies
Thin interbedded fabric reflects seasonal
evaporative cycles of circum basin climate
Dead Sea
Light layers
are
Gypsum
Dark layers
are
Dolomite
Evaporites as Time Markers
Hierarchical classification
of climate drivers,
with temporal scale of
operation (vertical axis)
and relative temperature
change effected at
each ordinal scale
(horizontal axis).
[after Gehard et al (2001)]
Evaporites as Time Markers
Unique & strong ties exist & constrain
the timing of evaporite accumulations.
These linear belts of marine &
lacustrian evaporites coincide with:
Arid climates
Plate tectonic setting
Origin of Evaporites
Lack of rainfall
Rain shadow
Width of continent
High mountains
Air System of the Arid Tropics
Where & when do thick
evaporites accumulate?
Lacustrian and Marine settings
adjacent to continental plate margins
during:Break up of continental plates
Collision & compression of continental
plates
Generation of structural & depositional
barriers
Commonly within Air System of Arid Tropics
Arid Climates Common in
Earth History
Examples/Evidence:
Evaporites of Mesozoic to Tertiary of
Middle East; Paleozoic & Mesozoic the
USA, Europe & Middle East
Arid Climates Common in
Earth History
Evidenced by:Salt Flat Evaporites
Arid Coastline Evaporites
Isolated Marine & Lacustrian
Evaporite Basins
Eolian sediments
Evaporite generation during
break up of continental
plates
Isolated linear belts of interior drainage.
Linear belts connected by restricted
entrance to the sea.
Regional drainage tends to flow away from
break up margin
Air system of the arid tropics
Wide envelope of surrounding continents.
Break Up Margin Evaporites
Mesozoic of Northern Atlantic
Isolated linear belts of interior drainage.
Linear belts connected by restricted
entrance to the sea.
Regional drainage tends to flow away from
break up margin
Air system of the arid tropics
Wide envelope of surrounding continents
Restricted
Entrances
To Sea
Regional
Drainage
Away
From Margin
Arid Tropics Air System
Wide Envelope of surrounding continents
Examples of Evaporites at
Break Up Margins
Mesozoic of Northern Gulf of Mexico
Mesozoic of North & South Atlantic
margins
Mesozoic of Yemen rift belt
Mesozoic & Tertiary of Eritrea
East African Rift
Dead Sea
Continental Collision Evaporites
Isolated linear belts of interior drainage.
Linear belts connected by restricted
entrance to the sea.
Regional drainage tends to flow into basin
Air system of the arid tropics
Wide envelope of surrounding continents.
Example of Evaporites at
Collision Margin
Current Arabian Gulf & underlying
Late Mesozoic to Tertiary
Isolated linear belts of interior drainage
Linear belts connected by restricted
entrance to sea
Regional drainage tends to flow into basin
Air system of the arid tropics
Wide envelope of surrounding continents
Regional
Drainage
Into Basin
Restricted
Entrance
To Sea
Isolated linear
Belt of interior
drainage
Arid Tropics Air System
Wide Envelope of surrounding continents
Examples of Evaporites at
Collision Margins
Current Arabian Gulf & underlying Late
Mesozoic to Tertiary
Silurian of Michigan Basin & Western New York
State
Devonian of Western Canada & NW USA
Permian of New Mexico & West Texas
Permian of Zechstein Basin
Mesozoic to Tertiary of southern South America
Tertiary of Mediterranean
Mesozoic & Tertiary in final phases of Tethys
Sea
Evaporite Generation Behind
Barriers
Isolated linear belts of interior drainage.
Linear belts connected by restricted
entrance to the sea.
Regional drainage tends to flow into basin
Air system of the arid tropics
Wide envelope of surrounding continents.
Examples of Evaporites
Behind Structural &
Depositional Barriers
Late Paleozoic to Early Mesozoic beneath Arabian
Gulf
Permian Khuff of Saudi Arabia, UAE & Oman
Upper Jurassic Hith Anhydrite of western UAE,
eastern Saudi Arabia, southern Kuwait and
western Iran
Evaporites trapped by original Hercynian horst &
block terrain at southern shore of Tethys Ocean.
Punctuated by limited access to sea & repeated
arid climatic events.
Restricted
Entrance
To Sea
Permian Khuff
Saudi Arabia
Oman & UAE
Structural &
Depositional
Barrier over
Hercynian
Horst Blocks
Arid Tropics Air System
Wide Shadow from Adjacent Continents
Restricted
Entrance
To Sea
Upper Jurrassic
Saudi Arabia
Kuwait, Iran
& UAE
Depositional
Barrier over
Hercynian
Horst Blocks
Tropical Air System !
Wide Shadow from Adjacent Continents
Examples of Evaporites
Behind Structural &
Depositional Barriers
Late Paleozoic to Early Mesozoic beneath
Arabian Gulf
Cretaceous Ferry Lake Anhydrite of
Florida
Evaporites trapped by structure and
depositional barrier.
Punctuated by limited access to sea &
repeated arid climatic events.
Conclusions
Arid climates common through earth history
Arid climates signaled by thick sections of evaporites in
marine & lacustrian settings adjacent to margins of
recently pulled apart continental plates &/or in
compressional terrains of colliding margins
Arid climates punctuate geologic column & so provide
time markers
Evaporites form stratigraphic marker horizons
&“sequence stratigraphy” of a section & their bounding
surfaces can be used to subdivide this, namely:
Upper surfaces of updip supratidal sabkha evaporite
cycles
Upper surfaces of downdip restricted playas & basin
evaporites