9.1 Weathering, Soils, Terrigenous Sediments
CLiMA TE: HUMID
a
TROPICAL
HUMID
TEMPERATE
ARID TO
SEMI-ARID
DESTRUCTI~ . :.:.:::,:.:.~'
AND DIS'"
: ~~.: :.~ . ~
SOLUTION OF
MOST ROCK:
MINERALS
I
MOST
PARENT
MINERALS
PRESERVED
I
.}
(CARBONATE DISSOLVED)
DESTRUCTION 1
OF OLIVINE,
AMPHIBOLES. -1..
HORNBLENDE,
PLAGIOCLASE,
ORTHOCLASE
IN PLACES
BAUXITE AND
FERRICRUSTS
b
SLOW DESTRUCTION
OF ROCK
MINERALS
DISSOLUTION
OF CARBONATES
~-rnID~~tIN PLACEl:
•
CALCRETE
AND / OR
SILCRETE
ALL PARENT
MINERALS PRESERVED
ZONE OF STRONG CHEMICAL-MINERALOGICAL
AND MECHANICAL WEA THERING (SOlL ZONE)
c
CONTRIBUTION
SOlL ZONE
TO SOLID RIVER LOAD
HUMID
TROPICAL
CliMATE
HUMID
TEMPERATE
ARID TO
SEM I-ARID
HIGH
__ L~~ _ __ _ ___ _ ----7
MEDIUM
MED IUM
LOW
- - -- -------- ---7
\ \/ .... ..' .
/,-1 ..!.
/ 'I,
/ 'j., 'L_H~I~G~H-------~
' . 1/ '
j/ ,PARENT ROCK AND ITS MINERALS
TO SEDIMENTARY
BASIN
TENDENCIES FOR
./
"'CLASTIC
SEDIMENTS
PREDOMINANCE
OF NEO-CLAY
MINERALS
DISSOLVED
RIVER LOAD
IN TOTAL HIGH ,
.::::::> RICH IN Na . (K), C;
Mg , HCOJ • Si0 2 ,
aUARTZ SAND,
MICA , CLAY,
IN TOTAL MEDIUM.
MINERALS DERIVED =!> OFTEN RICH IN
FROM BOTH SOlLS
Ca , Mg , HCO J
AND PARENT ROCKS
aUARTZ SAND,
WITH ABUNDANT
FELDSPAR: ETC.,
REDEPOSJTlON OF
OLDER CLAY
MINERALS
IN TOTAL LOW,
POOR IN MOST
MAIN CONSTTTUENTS
~ BUT LOCALL Y HIGH
DUE TO EVAPORATIO
OR DISSOLUTION
OF SALTS
415
Fig. 9.1. Qualitative relationship between climate,
weathering, and delivery of clastlc sediments as well
as dissolved materials into sedimentary basins. a Intensity and depth of destruction (or preservation) of
parent rock minerals and formation of clay-type neominerals (including oxides and hydroxides of Al and
Fe). b Different zones of weathering, resulting denudation, and river transport of particulate and dissolved load. c General trends in climatically-controlled
production of clastic sediments and the input of dissolved constituents into sedimentary basins. Note
that the temperate and especially the arid to semi-arid
regions can deliver substantial amounts of unchanged
parent rock material and nonaltered minerals (including clay minerals)
CLiMA TE: HUMID
a
TROPICAL
HUMID
TEMPERATE
ARID TO
SEMI-ARID
DESTRUCTI~ . :.:.:::,:.:.~'
AND DIS'"
: ~~.: :.~ . ~
SOLUTION OF
MOST ROCK:
MINERALS
I
MOST
PARENT
MINERALS
PRESERVED
I
.}
(CARBONATE DISSOLVED)
DESTRUCTION 1
OF OLIVINE,
AMPHIBOLES. -1..
HORNBLENDE,
PLAGIOCLASE,
ORTHOCLASE
IN PLACES
BAUXITE AND
FERRICRUSTS
b
SLOW DESTRUCTION
OF ROCK
MINERALS
DISSOLUTION
OF CARBONATES
~-rnID~~tIN PLACEl:
•
CALCRETE
AND / OR
SILCRETE
ALL PARENT
MINERALS PRESERVED
ZONE OF STRONG CHEMICAL-MINERALOGICAL
AND MECHANICAL WEA THERING (SOlL ZONE)
c
CONTRIBUTION
SOlL ZONE
TO SOLID RIVER LOAD
HUMID
TROPICAL
CliMATE
HUMID
TEMPERATE
ARID TO
SEM I-ARID
HIGH
__ L~~ _ __ _ ___ _ ----7
MEDIUM
MED IUM
LOW
- - -- -------- ---7
\ \/ .... ..' .
/,-1 ..!.
/ 'I,
/ 'j., 'L_H~I~G~H-------~
' . 1/ '
j/ ,PARENT ROCK AND ITS MINERALS
TO SEDIMENTARY
BASIN
TENDENCIES FOR
./
"'CLASTIC
SEDIMENTS
PREDOMINANCE
OF NEO-CLAY
MINERALS
DISSOLVED
RIVER LOAD
IN TOTAL HIGH ,
.::::::> RICH IN Na . (K), C;
Mg , HCOJ • Si0 2 ,
aUARTZ SAND,
MICA , CLAY,
IN TOTAL MEDIUM.
MINERALS DERIVED =!> OFTEN RICH IN
FROM BOTH SOlLS
Ca , Mg , HCO J
AND PARENT ROCKS
aUARTZ SAND,
WITH ABUNDANT
FELDSPAR: ETC.,
REDEPOSJTlON OF
OLDER CLAY
MINERALS
IN TOTAL LOW,
POOR IN MOST
MAIN CONSTTTUENTS
~ BUT LOCALL Y HIGH
DUE TO EVAPORATIO
OR DISSOLUTION
OF SALTS
415
Fig. 9.1. Qualitative relationship between climate,
weathering, and delivery of clastlc sediments as well
as dissolved materials into sedimentary basins. a Intensity and depth of destruction (or preservation) of
parent rock minerals and formation of clay-type neominerals (including oxides and hydroxides of Al and
Fe). b Different zones of weathering, resulting denudation, and river transport of particulate and dissolved load. c General trends in climatically-controlled
production of clastic sediments and the input of dissolved constituents into sedimentary basins. Note
that the temperate and especially the arid to semi-arid
regions can deliver substantial amounts of unchanged
parent rock material and nonaltered minerals (including clay minerals)