176
PROGRADING
DELTA -TlDAL
FLAT COMPLEX
a
PULL·APART BASIN,
:t FILLED WITH
RIVER-DERIVED
HIGH
WIDE SHELF WITH
TIDES
BIOCLASTS
SEDIMENTS
SLOPE BASIN
Chapter 4 Adjacent Seas
SEASONAL UPWELLING. HIGH FERTllITY,
AND PRODUCTION OF DIATOMS
SPREADING AXIS (TROUGH)
OF PULL -APART BASIN
GRAVITY MASS FLOWS
(MAINLY MUD
TUR BIDITES)
SUBMARINE
CANYONS
YOUNG
BASIN
PLAIN
OUTFLOW OF
SURFACE WATER
OCEANIC
SPREADING
RIDGE
INFLOW OF
NUTRIENTRICH , COLD
INTER -
MEDIATE
WATER
b
c
d
SLOPE SEDIMENTS
(BELOW UPWELlING)
SEDIMENTS OF
PULL-APART BASIN
AB YSSAL SEDIMENTS
AT WIDE ENTRANCE OF GULF
' " I
I
I
I
I
E
o
o ..,.
LAMINATED
DIATOMACEOUS
OOZE (VARVES)
HOMOGENEOUS
DIATOM. MUD
~:=:::'t>- T HIN MUD
TURBIDITES
DIATOM . MUD AND
MUD TURBIDITES
MUD FLOW , SLUMPS
DOLOMITE
CHERT
DIATOM. MUD AND
MUD TURBIDITES
DIATOM . MUD
MASS FLOW
I:P-~~- SAND AND
GRAVEL
o
o
CII
~~~SANDY
TURBIDITE
LAMINATED DIATOM. MUD
~;l~ DOLE RITE SILL
DIATOM. MUD OR
MUDSTONE AND
MUD TURBIDITES
F='~f-- DIATOMITE
(VARVED)
THIN DOLOMITIC
INTERBED
Fig. 4.5. a Gulf of California-type marine strike-slip
basin, with several deep spreading centers and wide,
deep opening to the ocearr. lnflow of intermediate,
cold and nutrient-rich wlliter; causing seasonal
upwelhng and high plankton productivity along both
Quatemary climatic changes and sea-Ievel tluctuations obviously exerted only a limited influence' on
DOLERITE
INTRUSION
OCEANIC CRUST
coasts of the gulf. b-d Simplified sediment sections
at different sites within the gulf (locations marked in
a). (Based on van Andel 1964; Calvert 1966; Curray,
Moore et al. 1982a)
the sediments of the Gulf of California. Drilling
cores display thick alternat ions between laminated