ISES
Magnetostratigraphy of upper Miocene-lower Pliocene sediments of the Black Sea Basin (Taman Peninsula, Russia)
Iuliana Vasiliev
1,*, Alexandr Iosifidi
2, Alexei Khramov
2, Wout Krijgsman
1, Cor Langereis
1, Vicktor Popov
2, Marius Stoica
3, Vika Tomsha
3, Serghei Yudin
41
Paleomagnetic Laboratory ’Fort Hoofddijk’, Department of Earth Sciences, Utrecht University, The Netherlands;
2All-Russia Petroleum Research Exploration Institute (VNIGRI), St.Petersburg, Russia;
3Faculty of Geology and Geophysics, Bucharest University, Romania,
4Faculty of Geology, St. Petersburg State University, St. Petersburg, Russia. *e-mail: (vasiliev@geo.uu.nl)
Introduction
During the late Miocene to early Pliocene (~11 to 3 Ma), the Eastern Paratethys domain extended from the Dacian Basin in Romania to the Aral Sea in Kazakhstan (Fig. 1). The Paratethys became progressively isolated from open ocean system, resulting in environments marked by varying salinities with marine to brackish and fresh water conditions. The Mio-Pliocene chronostratigraphic scale for the Eastern Paratethys encompasses the regional Sarmatian, Maeotian, Pontian and Kimmerian/Dacian stages, which are all defined on the basis of characteristic faunal assemblages endemic to Paratethys Sea. Correlation to the global Geological Time Scale is highly debated because radiometric age determinations are scarce and magnetostratigraphic studies are generally controversive (e.g. Trubikhin, 1977; Pevzner and Chikovani, 1978; Trubikhin, 1989). As a consequence, the ages of the Paratethyan stage boundaries can differ more than a million years in the various geological time scales (see Vasiliev et al., 2004 ).
Methods
In this paper, we aim to establish a magnetostratigraphic framework for the upper Miocene-lower Pliocene successions of the Black Sea Basin (Fig. 2). The Zheleznyi Rog (Iron Cape) section on the Black Sea margin of the Russian Taman Peninsula was selected. One volcanoclasic layers from upper Sarmatian deposits have been radiometrically dated using
40Ar/
39Ar method.
Results
Our magnetostratigraphy sustains both, earlier obtained, black and white patterns of Trubikhin (1989) and Pevzner and Semenenko (2003) despite of the different interpretation given by the two papers. Additional
40
Ar/
39Aage constrains indicate that important non-deposition and/or erosion let to significant hiatuses in the Meotian part of the Zheleznyi Rog section (Fig. 4). The
40Ar/
39Ar dating the volcanoclastic layer from Zhelezyi Rog, Taman Peninsula–Russia yielded a homogeneous age population at 8.7 ± 0.09 Ma (Fig. 3). This
40
Ar/
39Ar dating indicate that the Sarmatian/Meotian boundary in the Eastern Paratethys has to be younger than 8.7 Ma, in agreement with the magnetostratigraphy provided by Vasiliev et al., 2004 based on the Sarmatian-Meotian section in Carpathian foredeep.
Figure 2. Schematic lithological column and polarity zones for Zheleznyi Rog section. Position of dated volcanoclastic layer is indicated. Eastern Paratethys substages are given next to lithology. In polarity columns black (white) denotes normal (reversed) polarity intervals. Different symbols in declination/inclination plots represent reliable direction of demagnetisation and the steps are according to legend (inset in right-hand side). Representative demagnetization diagrams (a-j), after tilt correction. Selected examples are displayed in stratigraphical order from youngest (a) to oldest (j). Solid (open) circles denote projection on the horizontal (vertical) plane and the attached numbers indicate temperatures in ºC.
Figure 1. a) Schematic palaeogeographic map of the late Miocene/early Pliocene, showing the Paratethys area and the present-day land configuration. The big star locates the Zheleznyi Rog (ZR) section on Taman Peninsula, Russia. The small star indicates the position the Rîmnicu Sărat section, studied in Romania. b) Zheleznyi Rog section.
Figure 4. . Review of the paleomagnetic polarity patterns obtained for the Zheleznyi Rog section by Pevzner et al., 2003, Trubickin et al., 1989 and this research (in the let hand side). The multiple correlations of the magnetic polarity sequence to the APTS are presented. In the right hand side our correlation is indicated. The solid line between the section record and APTS connect (interepretative) simultaneous polarity boundaries. The names of the subchrons are in the column attached to the APTS. A to c are images of visible brake in the accumulation of the sedimentary deposits. a) Photograph of the distinct reddish layer marking the beginning of the Kimmerian; b) photograph of an intra upper Meotian unconformity and c) photograph at the lower Meotian- upper Meotian transition. The upper Meotian starts with the layer containing pebbly breccias and olistostroms.
Figure 3. Results of dated volcaniclastic layer.
NovorossianPortaferrian
Declination Inclination
8.70 Ma
40Ar/39Ar 8.70 Ma
40Ar/39Ar
-475 -450 -425 -400 -375 -350 -325 -300 -275 -250 -225 -200 -175 -150 -125 -100 -75 -50 -25 0
Stratigraphic level (m) SarmatianMeotianPontian Kimmerian Me 1Me2Sm3OdessianPortafferian
180 360 -90 0 90
(420-580 oC) (270-420 oC) (100-270 oC)
(50-100 mT) (0-20 mT) (20-45 mT)
LEGEND for components
TR 125.3B
th N
up/W
-133.63
100
180 ºC 200
210 340
TR 181.1A
th
N up/W
-399.05
20 ºC 80
140 100
210 TR 107.3B
th
N up/W
-167.17 20 ºC
100 150 210
240-340
TR 141.3
R-af
N up/W
-460.55
0 mT
10
15 20 TR 027.2
th
N up/W
-268.90
420
50 ºC 170 290
TK 001.3
R-af
up/W N
-89.21
20 mT 80
45 32
TH 030.1A
af
up/W N
-302.97
10 13
7 34
19 25
0 mT TR 032.3A
af
up/W N
-264.05 0
10 mT 31
19
TR 150.1
af
N up/W
-450.52
0 mT 10
20 40
TK 087.1A
th
N up/W
-30.52
100 ºC
200
250 485
i j
g h
e f
c d
a b
Marine transgression
(Krijgsman et al., 2010)
Volcaniclastic layer
Preliminary dated at ~8.7 Ma
5.0
6.0
7.0
8.0
9.0 4.5
5.5
6.5
7.5
8.5 Age(Ma)
APTS 2004
C3An.1n
C3An.2n
C3Bn
C4n.1n
C4n.2n
C4An
C3n.4n
C3Ar
C3Br.2r
C4r.2r C4r.1r
C3n.3n C3n.2n C3n.1n
C3An.1r
C4r.2r-1n
C3r
-275 -250
Me 2
-325
Me 2 -300
Me2
?
?
?
?
Me 1
-475 -450 -425 -400 -375 -350
Sm 3
-225 -200 -175 -150 -125 -100
NovorossianPortaferrian OdPfMe 2
-75 -50 -25 0
Km
MSC interval Pf
Km
-89 m -92.6 m
Me1 Me2
Me2
clay pebbels &
olistostroms
Picture a
Picture b
Picture c
Picture c Picture b Picture a
NovorossianPortaferrian
-475 -450 -425 -400 -375 -350 -325 -300 -275 -250 -225 -200 -175 -150 -125 -100 -75 -50 -25 0
SarmatianMeotianPontian Kimmerian Me 1Me 2Sm 3OdessianPortafferian
MeotianPontianKm upperlowerupper
50
100
150
200
250 0
Chron 6 = C3ArChron 7 = C4nGilbert
Pevzner &
Semenenko 2003
MeotianPontianKm upperlowerupper Chron 5 = C3AnChron 6 = C3ArGilbert
Trubikhin, 1989
This paper
a
b
c
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
0 10 20 30 40 50 60 70 80 90 100
Ar-Ages in Ma
W E IG HTE D P L ATE AU 8.70 ± 0.09
TOTAL F US ION 8.71 ± 0.09
NOR MAL IS OC HR ON 8.71 ± 0.09
INVE R S E IS OC HR ON 8.71 ± 0.09
MS W D 1.61
S ample Info
G las s Iuliana AL
IR R = VU78
J = 0.0026607 ± 0.0000266
Cumulative 39Ar Released (%)
Age (Ma)
INCREMENTAL HEATING
8.70 ± 0.09 Ma
Laboratory of Isotope Geology Vrije Universiteit, Amsterdam The Netherlands
0 200 400 km
50ºN
35ºN 40ºN 45ºN
20ºE 30ºE 40ºE 50ºE 60ºE
Black Sea
Casp
ian Se a
Hungary
Ukraine
Russia
Turkey
Kazahstan
RM
RM
ZR ZR
a
Eastern Paratethys (Black Sea)
Zheleznyi Rog section in Taman Peninsula - Russia (Miocene - Pliocene)
Kimmerian
Pontian Meotian
Sarmatian
