PRESENTATION OUTLINE

2. 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

3. 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)

4. 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)

5. 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

6. 10 52oE 54oE 56oE I R A N 40 40 N A R A B I A N MASANDAM PENINSULA 20 Strait of Hormuz Wind direction of “Shamal” 20 40 40 10 40 G U L F 26oN 40 Ras Al Khaimah GULF OF OMAN 20 Fujairah Dubai North Eastern Coast Q A T A R G R E A T Northwest Coast 10 10 10 40 10 P E A R L 20 Ras Ghanada 10 Jabal Odaid 10 10 B A N K ABU DHABI B A R R I E R Jabal Dhanna Al Ain Khor Al Bazam 10 24oN O M A N Central Coast Western Coast S A U D I A R A B I A U N I T E D A R A B E M I R A T E S 50 km Major coastal provinces of the United Arab Emirates and the bathymetry of the Southern Arabian Gulf in fathoms (modified from Purser, 1973).

7. Western Coastal Margin of the United Arab Emirates Western Coast of the United Arab Emirates

9. High Intertidal Cyanobacterial Flats Intertidal Carbonate Flats Earlier High Energy Beaches Supratidal Sabkha Evaporites

10. Ptygmatic Anhydrite & Storm Washover Diapiric Anhydrite After Gypsum Upper Intertidal Cyanobacteria Mats

11. Deflation Surface of Aeolian Carbonate

13. Sabkha Sediments Basin Margin Carbonates

14. Upper Tidal Flat Dolomite Sabkha of the “Guadalupian” Permian Seven Rivers Formation, of the Seven Rivers Embayment, New Mexico. Supratidal Gypsum Windblown & Fluvial Silts

15. Collapse Breccia in the Seven Rivers Formation Dark Canyon, New Mexico. Upper Tidal Flat Dolomites Collapse after Evaporites

16. Upper tidal flat dolomites Basinal evaporites

17. 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

18. Dead Sea

21. Light layers are Gypsum Dark layers are Dolomite

23. 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)]

24. 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

25. Origin of Evaporites Lack of rainfall • Rain shadow • Width of continent • High mountains • Air System of the Arid Tropics

26. Where & when do thick evaporites accumulate? • Break up of continental plates • Collision & compression of continental plates • Generation of structural & depositional barriers Lacustrian and Marine settings adjacent to continental plate margins during:- Commonly within Air System of Arid Tropics

27. Arid Climates Common in Earth History Evaporites of Mesozoic to Tertiary of Middle East; Paleozoic & Mesozoic the USA, Europe & Middle East Examples/Evidence:

28. Arid Climates Common in Earth History • Salt Flat Evaporites • Arid Coastline Evaporites • Isolated Marine & Lacustrian Evaporite Basins • Eolian sediments Evidenced by:-

29. 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.

30. 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

31. Restricted Entrances To Sea Isolated linear Belt of interior drainage Regional Drainage Away From Margin Arid Tropics Air System Wide Envelope of surrounding continents

32. 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

33. 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.

34. 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

35. Regional Drainage Into Basin Restricted Entrance To Sea Isolated linear Belt of interior drainage Arid Tropics Air System Wide Envelope of surrounding continents

36. 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

37. 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.

38. Examples of Evaporites Behind Structural & Depositional Barriers • Permian Khuff of Saudi Arabia, UAE & Oman • Upper Jurassic Hith Anhydrite of western UAE, eastern Saudi Arabia, southern Kuwait and western Iran Late Paleozoic to Early Mesozoic beneath Arabian Gulf Evaporites trapped by original Hercynian horst & block terrain at southern shore of Tethys Ocean. Punctuated by limited access to sea & repeated arid climatic events.

39. Restricted Entrance To Sea Structural & Depositional Barrier over Hercynian Horst Blocks Permian Khuff Saudi Arabia Oman & UAE Arid Tropics Air System Wide Shadow from Adjacent Continents

40. Restricted Entrance To Sea Depositional Barrier over Hercynian Horst Blocks Upper Jurrassic Saudi Arabia Kuwait, Iran & UAE Tropical Air System ! Wide Shadow from Adjacent Continents

41. 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.

42. 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