Strontium Isotopic Variations of Neoproterozoic Seawater ...
TIMANIAN OROGENY AND LATE NEOPROTEROZOIC SUBDUCTION
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Transcript of TIMANIAN OROGENY AND LATE NEOPROTEROZOIC SUBDUCTION
TIMANIAN OROGENYAND
LATE NEOPROTEROZOIC SUBDUCTION
V. PEASE, STOCKHOLM UNIVERSITY
EXTENT OF TIMANIAN OROGENY
Sediment cover (undifferentiated)
Paleozoic orogens
Timanian age complexes
Precambrian crystalline basement
Rift basins
500 km
Black Sea
N65°
E10° E20° E30° E40° E50° E60°
N55°
N45°
East Eur opean Cra ton
BalticSea
Pericaspian Basin
PEASE et al., IN PRESS
Caledonides
500 km
Caspian Sea
Black Sea
Donets basin
Pericaspian Basin
East Eur opean Craton
GEOMETRY OF TIMANIAN OROGENY
10 cm 1 m
10 cm 10 mm
FORELAND BASIN
1 km
2
3
4
0 100 200 300 400 500 600 km
cratonbasement
basalt Late Paleozoicsediments
SW NETIMAN RANGEMEZEN BASIN
555 Ma
Late Neoproterozoic
Early & MiddleNeoproterozoic
GRAZDANKIN, 2004; MARTIN et al., 2000
FORELAND BASIN
TIMAN RANGE FOLD & THRUST BELT
LORENTZ et al., 2004
SW NE
Mesozoic
Quaternary Quaternary
Paleozoic
overlying units (not exposed)
Tabuyevskaya Group
Tarkhanovskaya Group
Mikulkinshaya Groupand underlying Neoproterozoic units
Neoproterozoic pericratonic sedimentsof BalticaN
eoproterozoic
FORELAND FOLD & THRUST BELT
LORENTZ et al., 2004
TIMAN RANGEREGIONAL
METAMORPHISMgr+bt+mu+pl+k-spar+q ky st
gr-bt thermometerGASP barometer
+ +
0400 500
T (°C)
andalusite
sillimanite
kyanite
Bohlen et al., 1991
600 700 800
0.2
0.4P (GPa)
0.6
0.8
1.0
0400 500
T (°C)
andalusite
sillimanite
kyanite
Bohlen et al., 1991
600 700 800
0.2
0.4P (GPa)
0.6
0.8
1.0
0400 500
T (°C)
andalusite
sillimanite
kyanite
Bohlen et al., 1991
600 700 800
0.2
0.4P (GPa)
0.6
0.8
1.0
LORENTZ et al., 2004
TIMANPECHORAREGION
VENDIAN ACCRETEDTERRANES/URALIANFORELAND ANTICLINES
BOLSHEZEMEL ZONE
URALIAN OCEANICCRUST & VENDIAN BASEMENT
PECHORA ZONE
IZHMA ZONE
1
5
47
8
2
3
44°E 52°E 60°E
66°N
65°N
63°N
WESTSIBERIANBASIN
Barents Sea
Kara Sea
POLA
R U
RALS
S YKTYVKAR
KaninPeninsula
UKHTA
TIMAN R
ANGE
INTA
VORKUTA
100 kmgranitoidsediment & gneiss
A
B
1-Dinyu1-Novaya 1-Ronayol 1-West Dutovo1-Malole-bedinskaya
2-CharkayuLunvozh
1-NorthSavinobor
Paleozoic&
younger
Paleozoic&
younger
Paleozoic&
younger
Paleozoic&
younger
Paleozoic&
younger
Paleozoic&
younger
Paleozoic&
younger
4045 m
7
4766 m(bottom)
4230 m
9
2
8
diorite (565 Ma)
5
4501 m(bottom)
4240 m4
4303 m(bottom)
3600 m
4
3900 m(bottom)
3500 m
1, 63800 m(bottom)
3005 m
3
3208 m(bottom)
4844 m
10
4900 m(bottom)
gabbro, dolerite, or diorite
granodiorite
meta-andesite orandesitic tuffsmeta-basalt orbaslatic tuffs
vertical scale
unconformityfracture
40 m
PECHORA ZONE MAFIC COMPLEX
b.
a.
270°
70°130°
NeoproterozoicEnganepe Complex
Cambro-Ordoviciansediments
HINTERLAND
REGIONAL UNCONFORMITY & RETURN TO PASSIVE MARGIN
• AGE OF OVERLYING SEDIMENTS <500 Ma (PEASE, UNPUBLISHED DATA)
• AGE OF NEOPROTEROZOIC OPHIOLITES ca. 670 Ma (KHAIN ET AL, 1999)
KVARKUSH BLUESCHIST
BECKHOLMEN & GLODNY, 2005
•350-400 °C•7-8 Kilobars
•540 Ma
TIMANPECHORAREGION
VENDIAN ACCRETEDTERRANES/URALIANFORELAND ANTICLINES
BOLSHEZEMEL ZONE
URALIAN OCEANICCRUST & VENDIAN BASEMENT
PECHORA ZONE
IZHMA ZONE
1
5
47
8
2
3
44°E 52°E 60°E
66°N
65°N
63°N
WESTSIBERIANBASIN
Barents Sea
Kara Sea
POLA
R U
RALS
S YKTYVKAR
KaninPeninsula
UKHTA
TIMAN R
ANGE
INTA
VORKUTA
100 kmgranitoidsediment & gneiss
A
B
SCHEMATIC PECHORA X-SECTION
TIMANIAN OROGENESIS
ONSET? ±600 Ma
PEAK METAMORPHISM? ±550 Ma (REGIONAL P/T 600°C, 25-28 KM)
STRUCTURAL STYLE? NW-STRIKING, SW-THRUSTING, OCEAN/ARC- CONTINENT COLLISION
END? 500 Ma
TECTONIC RECONSTRUCTIONS
Greenland
Iceland
Baffin is.
Alaska
Russia
SVALBARD
FranzJosefLand
NOVAYA
ZEM
LYA
SEVERNAYAZEMLYA
180°
90°E90°W
TAIMYR
Kara Sea
Barents Sea
SeaLaptev
East Siberian Sea
Chukchi Sea
POLARURALS
LOM
ONOSO
V RID
GE
2000
3500
2000
0°
3500
v
v
v
v
EURASIANBASIN
CT
NT
PECHORA
BASIN
REGIONAL OVERVIEW
CRITERIA FOR SUBDUCTION TECTONICS
STERN, 2005
•OPHIOLITES•BLUESCHISTS•UHP METAMORPHISM
NO SMOKING GUN, BUT…..
THE NEOPROTEROZOIC TIMANIDE OROGEN
OF EASTERN BALTICA
eds. GEE & PEASEGEOL. SOC.
LONDON MEMOIR 30, 2004
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