mml
VERTICAL
1000 V. MOVEMENTS
00.000
SHORT ~ATION
i
Ice-sheet
areas
10. 000 ~']['" - -.
T Mountains
_
ILONG DURATION
Continental
High relief
1.000+-~I--_ a _ re_ a_ s _~
~ Continental
~ Law rel ief
Sedimentation Rates
93
DENUDATION SEDIMENTATION
RATES
RATES
Sea level rise l 1"' 7' <"--.,.,-..:----:'---:---t
-10.000 y. B P.
l{ Lf' Coral reef
I
DELTAS
Himalaya
I
Nlbrth Sea Tidal
'r flats
T
, ¢. since 8OOOY.
I , IKiel Bay
I ,
since 100 Y
Drainage areas :
Colo rado T D -SHELF
~
ar eas
--11-_
~~~~7:~nks
100
I I
I ,
o CONTINENTAL
II _ SLOPE
Amazonas ~
Mississ .
T
Congo
Mid
Oceamc
Ridges
D " DEEP SEA
T
CALCAREOUS
OOZES
10T---------~--------~~------__t
~ ~ Sill CEOUS
OOZES
I I
: 1 RED CLAY
1~---------L--------~----------~
Fig. 3.13. Rates of vertical crustal motion, of denudation, and of sedimentation rates. Scale in
mm/lOOO years, also called "Bubnoffs" (B), or m/million years. Postglacial sea level rise for comparison: 100 m in 5000 yrs. Note interaction with recently deglaciated land (arrows left) and with
coral growth rates (arrows riJ?ht). [E. Seibold, 1975, Naturwissenschaften 62: 62; modified]
To apply these figures to ancient sediments, one has to correct them for compaction, that is, for a loss of porosity of about 40 % in sands, to about 70 % in muds.
On the whole, high rates occur at the edges of the continents, especially in estuaries and marginal basins with river influx. Exceptionally high values (up to 10 m
per year) are recorded off southern Alaska glaciers. The lowest sedimentation rates
occur in abyssal regions far away from the continents. Characteristic values for
continental slopes are 40 to 200 mm/IOOO years, under upwelling areas even up to
1000 mm/IOOO years, for the deep sea I to 20 mm/IOOO years. Coral reefs can build
up at rates of 1 cm per year, that is , 10000 mm/looO years! (see Sect. 7.4).
The most reliable estimates of sedimentation rates are possible in the case of
annual layers or varves. Counting of the varves in the Black Sea yields a rate near
400 mm/IOOO years, and in a bay off the Adriatic Island Mljet, 250 mm/lOOO years
(Fig. 3.14). In the Santa Barbara Basin off California, varve counts yield 1 mm/year,
in the Gulf of California 1-4 mm/year. Many millenia of temperture variations and
upwelling history can be reconstructed from the varves in the Gulf sediments and in
VERTICAL
1000 V. MOVEMENTS
00.000
SHORT ~ATION
i
Ice-sheet
areas
10. 000 ~']['" - -.
T Mountains
_
ILONG DURATION
Continental
High relief
1.000+-~I--_ a _ re_ a_ s _~
~ Continental
~ Law rel ief
Sedimentation Rates
93
DENUDATION SEDIMENTATION
RATES
RATES
Sea level rise l 1"' 7' <"--.,.,-..:----:'---:---t
-10.000 y. B P.
l{ Lf' Coral reef
I
DELTAS
Himalaya
I
Nlbrth Sea Tidal
'r flats
T
, ¢. since 8OOOY.
I , IKiel Bay
I ,
since 100 Y
Drainage areas :
Colo rado T D -SHELF
~
ar eas
--11-_
~~~~7:~nks
100
I I
I ,
o CONTINENTAL
II _ SLOPE
Amazonas ~
Mississ .
T
Congo
Mid
Oceamc
Ridges
D " DEEP SEA
T
CALCAREOUS
OOZES
10T---------~--------~~------__t
~ ~ Sill CEOUS
OOZES
I I
: 1 RED CLAY
1~---------L--------~----------~
Fig. 3.13. Rates of vertical crustal motion, of denudation, and of sedimentation rates. Scale in
mm/lOOO years, also called "Bubnoffs" (B), or m/million years. Postglacial sea level rise for comparison: 100 m in 5000 yrs. Note interaction with recently deglaciated land (arrows left) and with
coral growth rates (arrows riJ?ht). [E. Seibold, 1975, Naturwissenschaften 62: 62; modified]
To apply these figures to ancient sediments, one has to correct them for compaction, that is, for a loss of porosity of about 40 % in sands, to about 70 % in muds.
On the whole, high rates occur at the edges of the continents, especially in estuaries and marginal basins with river influx. Exceptionally high values (up to 10 m
per year) are recorded off southern Alaska glaciers. The lowest sedimentation rates
occur in abyssal regions far away from the continents. Characteristic values for
continental slopes are 40 to 200 mm/IOOO years, under upwelling areas even up to
1000 mm/IOOO years, for the deep sea I to 20 mm/IOOO years. Coral reefs can build
up at rates of 1 cm per year, that is , 10000 mm/looO years! (see Sect. 7.4).
The most reliable estimates of sedimentation rates are possible in the case of
annual layers or varves. Counting of the varves in the Black Sea yields a rate near
400 mm/IOOO years, and in a bay off the Adriatic Island Mljet, 250 mm/lOOO years
(Fig. 3.14). In the Santa Barbara Basin off California, varve counts yield 1 mm/year,
in the Gulf of California 1-4 mm/year. Many millenia of temperture variations and
upwelling history can be reconstructed from the varves in the Gulf sediments and in