Geological and tectonic evolution of the Arctic Ocean Course: Particularities

Features of Cold Region Geology



by
Alexey A. Krylov,
Institute of

Lectures 2 - 3

Grenvillian supercontinent that formed ~1 Ga.
Arctida structures within Rodinia: Svalbard,

Continental masses

Continental blocks of Arctida

Oceanic basins

Arctida located between the Canadian margin of Laurentia, the southwestern margin of Siberia and the northeastern margin of Baltica.

basins
The breakup of the Rodinia was accompanied by the destruction

Active continental margin located close to the Timan–Ural margin of Baltica

Inferred position of spreading zones

Active continental margins

basins
Inferred position of spreading zones
Active continental margins
Svalbard plate collision -

The SW margin of Siberia was in a setting of active continental margin of pacific type.

The birth of the Iapetus Ocean on the margins of Laurentia and Baltica.

basins
Inferred position of spreading zones
Active continental margins
Iapetus was characterized by

Continental crust breakup along the eastern (modern coordinates) margin of Baltica with the formation of the oceanic floor of the Ural paleoocean

basins
Inferred position of spreading zones
Active continental margins
The end

basins
Inferred position of spreading zones
Active continental margins
The Silurian–Devonian boundary: closure

The Kara microcontinent already was located directly near the Taimyr margin of Siberia.

The collisional event between Laurentia and Baltica and their unification into Laurussia.

basins
Inferred position of spreading zones
Active continental margins
The blocks of Arctida

Rheic Ocean - the oceanic space between Laurentia and the African margin of Gondwana, was in active closure

basins
Inferred position of spreading zones
Active continental margins
The global tectonic regime

basins
Inferred position of spreading zones
Active continental margins
The Rheic ocean disappeared….

basins
Inferred position of spreading zones
Active continental margins
The appearance of Pangea…
Arctida….

(Fl 533, CESAR-6, FL 437) on the Alpha Ridge, and

PS87/106

PS87/106

COLLECTED UP TO DATE

on the Lomonosov Ridge drilled along the seismic profile AWI-91090.

of modern lithospheric plates;
2 – boundary of the Chukchi –

3 – idealized trajectory of the Chukchi – Arctic Alaska microplate during the opening of the Canada Basin

Rotational model of the Amerasian Basin Formation

Late Jurassic – Early Cretaceous (~150-140 Ma): breaking off the Chukotka – Arctic Alaska microplate from the Canadian Arctic Archipelago.

of upper mantle return flow: the reason for the extension

Earth Sciences
The process of detachment and subsequent movement of the

Alpha-
Mendeleev
Ridge

Canada
Basin

Makarov-
Podvodnikov
Basin

Alpha-
Mendeleev
Ridge

Canada
Basin

no Makarov-
Podvodnikov
Basin

was equal to its present area. Later, subsequent formation of

ORIGIN OF THE AMERASIAN BASIN

Alpha-
Mendeleev
Ridge

Canada
Basin

Makarov-
Podvodnikov
Basin

“Lomonosov
Ridge”

seasonality and high paleoproductivity.
Yellowish laminated siliceous ooze rich in diatoms,

Age: Campanian for Fl-437 (Dell’Agnese&Clark, 1994);
Campanian-Maastrichtian for CESAR-6, depending on whether diatoms, silicoflagellates or palinomorphs are taken as the prime biostratographic indicator.

mixed terrigenous-marine type of organic matter.
Origin: anoxic condition in an

AMERASIAN BASIN: MESOZOIC SEDIMENTS

of “the second zone of Cenozoic tectonic blocks” (a linear

55 Ma

Paleogene coincided with intervals where Corg depleted in 13C isotope.

2006
TEX86 temperatures in the Central Arctic during (and around) PETM.

1 2 3

in ACEX core was determined by calibration with well-dated ODP

2015
Closing of the Turgai Strait. The Arctic Ocean become isolated.

Units 2 and 1/6 of the ACEX.

in heavy fraction (size 0.05-0.1 mm) from ACEX sediments
Biosilica
Sandy silty

Paleogene

Neogene

Arctic at the Lomonosov Ridge during the early middle Eocene,

26 Ma hiatus at ~200 m below ocean floor.
Mesozoic
Paleogene
Neogene

subsidence of the Lomonosov Ridge by cooling and weighting of

absence of faults and tectonic deformations in the sediments above

values of osmium isotopes in the sediments accumulated "before hiatus"

The values of osmium isotopes also indicate the absence of a long hiatus (less than 400 thousand years, not 26 million!).

B" is true, then the sedimentary section contains Oligocene deposits.

2007]
Isolation of the Arctic Ocean till this time [O’Regan

ПРОБЛЕМА СРЕДНЕ-КАЙНОЗОЙСКОГО ПЕРЕРЫВА

PROBLEM OF THE MID-CENOZOIC HIATUS

Isolation: 49÷36.6 Ма

Eurasian Basin during isolation of the Arctic Ocean
subsidence model of

ПРОБЛЕМА СРЕДНЕ-КАЙНОЗОЙСКОГО ПЕРЕРЫВА

PROBLEM OF THE MID-CENOZOIC HIATUS

Falling sea levels could lead to erosion of sediments on the Lomonosov Ridge. Most likely this erosion does not exceed 400 Kyr.

assumption about the time of sea-ice occurrence in the Central

AND PERRENIAL ICE
Onset of the ice in Central Arctic: appearance

247 mbsf, in LU 2 (biosilica deposits) = 46 Ma

Amount of fraction 150-250 μm increased at 46.3 Ma. [St. John, 2008].
Sea-ice-related diatoms Synedropsis spp. found ~47 Ma [Stickley et al., 2009].

First seasonal ice appeared in the Central Arctic in the Middle Eocene

ONSET OF SEASONAL AND PERRENIAL ICE

abundance of ice-rafted debris (IRD). SST data do not support

- occurrence of large-sized single dropstones

Major
cooling
events

Major
warming
event

Major increases in sea-ice cover

EOCENE

SEASONAL AND PERRENIAL ICE
Px – Clinopyroxene;
Hbl – Hornblende;
Sid – Siderite;
P

Numbers: time during which the ice reaches the Fram Strait

along the ACEX borehole. Сhange of the mineral associations occurred

Paleogene

Neogene

13Ma

by quartz sandstones, quartz siltstones and quartzites.
Within LUs 1/3

Сhange of rocks assemblages found at the level of 159 m, which practically coincides with the change of associations of heavy minerals in LU 1/3.

1/2

1/3

1/4

1/6

2

0

100

200

300

mbsf

Qu sandstone

Qu sandstone

Quartzite

Quartzite

Qu sandstone - 3

Quartzite - 2

Quartz sandstone - 1

Dolerite - 1

Qu sandstone - 3

Sandstone - 9

Shale - 7

Qu gravelstone - 3

Sandstone - 2

Basalt - 2

Flint, Qu sandstone, Limestone, Shale

ONSET OF SEASONAL AND PERRENIAL ICE

Cpx/
Hbl

in the Middle Miocene (about 13 Ma). From that moment,

ONSET OF SEASONAL AND PERRENIAL ICE

is covered with pack ice. Lack of benthic and planktonic

2) Deglaciation.
Degradation of glaciers. The appearance of a large number of icebergs. The transfer of coarse material. Pack ice and icebergs are melting rapidly. The appearance of benthic and planktonic organisms. High rates of sedimentation.

3) Interglacial.
Modern Arctic Ocean. The predominance of clay and silt material. The abundance of benthic and planktonic organisms. The intermediate sedimentation rates.

rates
IRD
Start of bioproductivity
Seasonal
ice
Pelagic
sedimentation

intermediate
sedimentation rates

from ice-rafted debris
An angular quartz grain from ice-rafted sediment
A sample

shown that their IRD content can be correlated to the

Large amounts of IRD in the sediments coincide with the extension of the ice sheets over the continental shelves.

Contribution of glaciomarine material to pelagic sediments

Oxygen Isotope Stages (OIS), are related to chronological alternating of

MIS uses the balance of oxygen isotopes in stacked fossil plankton (foraminifera) deposits on the bottom of the oceans to build an environmental history of our planet.
The changing oxygen isotope ratios hold information about the presence of ice sheets, and thus planetary climate changes, on our earth's surface.

of foraminifera growth with the calculated "isotopic temperatures", the following

ToC = 17.0 – 4.52 (δ18Oc – δ18Ow) + 0.03 (δ18Oc – – δ18Ow)2,

Marine Isotopic Stages

where
δ18Ос – О-isotope from carbonate-CO2 and
δ18Оw – О-isotope from СО2, which is in equilibrium with water at 25оС.

δ18О = 18O/16O

discoveries demonstrate that favourable conditions for hydrocarbon generation and entrapment

- along the Arctic Alaskan margins (Mackenzie Delta–Prudhoe Bay),
- the Canadian Arctic Islands (Sverdrup–Ellesmere Basin), and
- on the Eurasian shelves (southern Barents Sea, western Siberia).

The primary source of these oil and gas accumulations is thought to be source-rock units of Pz and Mz age.

the Beaufort Mackenzie basin off northwestern Canada appear to be

Alaskan margin suggests that Eocene and Miocene sequences have given

OIL&GAS POTENTIAL OF THE CENTRAL ARCTIC

Eocene sediments from the Lomonosov Ridge by the IODP302 Expedition,

These strata are characterised by the widespread occurrence of large quantities of the freshwater fern Azolla deposited during the onset of the middle Eocene (about 50 Ma).

Yellow asterisks = Azolla locations

(wt%) and HI (mg HC/g TOC) between 56.2 and 44.4

HI and TOC values (Peters, 1986)
Modelled source-rock potential in the

deposited between 56.2 and 44.4 Ma along the Lomonosov Ridge

modeling for IODP-302 borehole (Mann et al., 2009).
Model shows

very good and good HC source potential on the Lomonosov

– Early Cretaceous (~150-140 Ma) due to breaking off the

2) The process of detachment and subsequent movement of the Alpha-Mendeleev Ridge away from the Barents Sea margin, accompanied by rift extension of the Makarov and Podvodnikov basins, occurred in the interval of 110-60 Ma.

3) Mesozoic sediments in the Amerasian Basin represented mainly by siliceous («diatom-bearing”) sediments.

4) Detachment of the Lomonosov Ridge from the Barents Sea margin and formation of the Eurasian Basin began ~58 Ma (Late Paleocene).

for the characterization of ACEX sediment. Age model “A” includes

CONCLUSION

6) During the late Paleocene-early Eocene terrigenous shelf sediments accumulated on the Lomonosov Ridge (and in the Eurasian Basin): LU3 in the ACEX-well. Accumulation of bio-siliceous sediments began in the Middle Eocene: LU2-1/6 in the ACEX-well. For a long time the Arctic Ocean was an isolated basin.

in the Middle Eocene and the further evolution of the

7) In the Late Eocene (36.6 Ma) Fram Strait opened and the isolation of the Arctic Ocean terminated. Pelagic terrigenous sediments of lithological units 1/6 - 1/1 began to accumulate.

9) The first pack ice in the central Arctic have appeared in the Middle Miocene (about 13 Ma). From that moment, trans-polar drift ice system began working.

(icebergs) was fairly stable in geological history. For the Eurasian