6.4 Marine Evaporites
a EVAPORITE BASIN AND SUBSURFACE FLOW REGIMES
. '.
SPRING MOUND OUTLET SEEPAGE
SEA
~~_ SABKHA
BRINEPOOL
~~ ! . . '.::. t.~!:. ~--\-I '~
- - - - T - - \ - - -_
-
~
METEORIC " ""'''
I
......... : .. .
INFLUX
"''\.~ ~
;' .1/
MARINE INFLUX
"%.~
-
/
} {
ACTIVE PHREATIC
BEDDED SALTS ~?
FLOW REGIME
. ~"",",-~
'f/
....,.~-=
______ ~S~O~U.2"I_LJN __ =-_ \-~-IM~~~~:Ll~~ ~LEA~~E~ - - - -
COMPACTION
;a:-~
MIXING OF FORMATION
FLOW
INCREASED THICKNESS WATER S AND BRINE.
OF EVAPORITES
CEMENTATION
T~~R~OBA~IC - ~:~~~~NB~~~ - - -D---w töESPREAD-DiÄGENETIC - - - -
FLOW
;~! CEMENTATION
ALTERATION
, ,
BRINE
DEHYDRATION OF EPAPORITE
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ANDCLAYMMINERALS
ZONE OF
METAMORPHISM
T>200·C
NON-EVAPORITIC
SEDIMENTS
± RELEASE OF BASE METALS AND HYOROCARBONS
b PRIMARY AND SECONDARY EVAPORITES
BonOM-NUCLEA TED AND
REWORKED GYPSUM
SABKHA (MUDFLAT)
DISPLACIVE HAllTE,
MICROKARST, CEMENT
/ ~ 8-' ~ ~
DEEP-WATER
_~~h~ ,:A."
-
JU , eil
- ........ ::iJ::U:~ 'V
MICROKARST
, @ 't:tt:ttö
HAllTE
~ ~ ~ ~ ~ • ,," AA~
~
"
----- . ""''''''''''''
GYPSU~ AND '_ ' 111111"1' 1 ~
.• -,-:.\:s?> ~::: § §g ~ •• ~
ANHYDRITE
-_ tttttttJ =. . . : ., . .. . .. . ,. ~.. ~
'f ... :::--,
-=•
CHAOTIC
fu
/ •• •• ~RIMARY EVAPORITES .....
HAllTE
Q
• ••••••••• ~...... •••
BonOM-NUCLEATED
SECONDARY EVAPORITES
AND REWORKED HAllTE
GYPSUM~ANHYDRITE t HALITE
.... ";:JJ.;. " \
:&.;t
PSEUDOMORPHS
.Q. :)j .-{- ~
:
I \
'\~ ro~~~r~A' ~ITE ~
tttttttJ
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gmra ?--9~
~~~ ~~ ff--\
GY~GHOS~!!'® ~ ~ --n~ ~~:~::~EH:i~~E ANO
REPLACIVE /
SADDLE DOLOMITE AT
SPARRY ANHYDRITE
HALITE-SHALE CONTACT
± SALT FLOW
275
Fig. 6.12. a Subsurface flow regimes below
evaporite basin. Right-hand side: increasing thickness of evaporites (e.g. due to subsurface salt dissolution) and downward shift of ± impermeable layer.
b Primary and secondary evaporites of gypsumanhydrite-dorninated system (left) and halite-dorninated system (right). (Modified and simplified from
Warren 1997). See text for further explanation