The 2600 BP and Little Ice Age Caspian highstands

1
The 2600 BP and Little Ice Age Caspian highstands

• S. B. Kroonenberg, G. M. Abdurakhmanov,
• E.N. Badyukova, S.C.M. Hakkeling, A. Kalashnikov,
  M. V. Kasatenkova, N.S.Kasimov, G.I. Rychagov,
  M.Yu. Slobodyan, A.A. Svitoch, H.B. Vonhof, F.P.
  Wesselingh, J.H. Zeeman

2
Water balance Volga inflow vs. evaporation
3
Contrasting Caspian sea-level curves for the last
600 ka (Varushchenko et al., 1987)
4
(No Transcript)
5
(No Transcript)
6
Why discrepancy age data?

• Sampling only lagoonal sediments indicate
  position highstand see recent dynamics
• Only doublevalved molluscs in living position
  (vertical) are same age as lagoonal deposits
• AMS dating on single mollusc doublets more
  reliable than conventional C14 on big samples
  (greater risk of contamination).

7
Caspian sea-level and Volga discharge
8
(No Transcript)
9
(No Transcript)
10
Volga delta
Holocene barrier complex
Lake Bolshoy Turali
2001 barrier lagoon
Caspian Sea
Terek delta
Caucasus
Turali study area
11
Hol.BC
1929 scarp
1995 barrier, lagoon
1929-1977 terrace
Late Khvalyn (Pleistocene) marine terrace
The Turali coastal section, Dagestan, Russia
12

• Turali site in the thirties no barrier no lagoon

13
Dagestan, Turali coast without barriers at
sea-level fall (1950)
14
1929
1941
1956
Coastal barriers Turali area, Dagestan
1929
1995
1941
Sea level
1956
15
(No Transcript)
16
Progradational clinoforms in 1929-1977 terrace,
Turali, Dagestan
17
Progradational clinoforms in 1929-1977 terrace,
Turali, Dagestan
18
GPR Profile through 1929-1977 terrace, Lenkoran,
Azerbaijan Storms, 2002
19
(No Transcript)
20
R
1986
R
1987
R
1988
R
1989
R
1991
R
1996
Barrier migration during sea-level
rise 1986-1996, Turali beach, Dagestan
80 m
21
Turali, Dagestan barrier geometry at rising
sea-level 1977-1995
1977-1988 continuous retreat 1988-1995 lagoon
deepens and widens
22
(No Transcript)
23
(No Transcript)
24

• Landwards dipping foresets in eroded washover
  lobes

25
Coarsening upwards sequence in transgressive
barrier, Tyulen Island, Caspian Sea
26
Caspian sea-level change according to TOPEX/
POSEIDON data (Cazenave et al, 1997)
Dec 1992
Aug 1996
27
(No Transcript)
28
(No Transcript)
29
Profile A Lenkoran
Sea level
GPR
30
(No Transcript)
31
Volga delta
Holocene barrier complex
Lake Bolshoy Turali
2001 barrier lagoon
Caspian Sea
Terek delta
Caucasus
Turali study area
32
Drilling through Turali barrier complex in the
30ies for experimental sulfate production
gravel on lagoonal clay
Section Turali Sulfat Canal barrier complex
(Rychagov, 1977, 1997)
33
Caspian Sea level in the Holocene (Rychagov, 1993)
34
2001
1950
dunes
spits
Outcrop, pit
Progra-dational phases Holocene Turali barrier
complex
GPR profiles
BT
Kan2
LG
Kan1
OT2
MT
35
progradational foresets
highstand washover lobe
Profile MT
section through Holocene barrier complex, Turali
36
GPR profile through Holocene barrier complex
(example)
37
progradation during sea-level fall
highstand washover
GPR section through Holocene barriers, Dagestan
38
Overview of results
39
Profiles studied
Kan1
OT21
BT
Kan 2
40
homogenized sandy soil
2370 /- 40 BP
lagoonal clay, doubleshelled molluscs, sand
with small ripples
2322 /- 37 BP
2517/- 41 BP
gravel,gravelly sand, southward foresets
Profile NP through 2nd phase barrier complex,
L.Bolshoy Turali
41
(No Transcript)
42
(No Transcript)
43
Molluscs in clay at base2747 /- 35 BP
44
2373 BP Cardium doublets in underlying sand 2366
BP Didacna doublets in same layer
45
dunes
LIA barrier
spits
2700- 2300 BP
46
New datings Holocene barrier complex
2700-2300 BP
Little Ice Age
LG 2350
NP 2370 2322 2517
OT2 2373, 2366BP
Kan 2
2603 2747
47
1400 BP -20m Derbent lowstand, Kura delta,
Azerbaijan (Boels et al., 2002)
Well
Datum Ca.1400 yrs BP
1844/-32 BP 2829/-33 BP
1368/-36 BP 1914/-29 BP
1414/-37 BP 1443/-29 BP
48
Caspian Sea level in the Holocene
2700-2300 BP highstand
LIA high- stand
lt1300BP lowstand
49
14C AGES OF MININO-2 LAYERS
(Gracheva et al., 2002)
50
(No Transcript)
51
Ice and deep sea core evidence 2600BP cooling
(Bond 1997)
52
Conclusions

• The Turali barrier complex originated during two
  major highstands between 2700-2300 BP (phase 1-5)
  and Little Ice Age (Phase 6)
• Both highstands coincide with major phases of
  global cooling and high precipitation in the
  Volga watershed, related to low solar activity
• Aggradational phases 1-5 suggest superimposed
  higher order cyclicity of a few decades (60-80 y)
  (NAO?)
• The 1977 AD lowstand coincides with cooler period
  with lower precipitation (NAO?)
• Do millennial and decadal cycles have opposite
  effects?