U.S.-Russia Joint Workshop on the Plate Tectonic Evolution of NE Russia

Stanford University Dec. 9-12, 2004Sponsored by the

U.S. National Science Foundation(Tectonics and International Divisions)

with travel support for Russian scientists shared byPlacer Dome, Shell International, Anadarko, Encana, Exxon,

Pacific Rim Geology Consultants for

Fall 2004 AGU Special Session in honor of Leonid ParfenovSan Francisco, CA, Dec. 16th

After the field 1999 Leonid and Irina’s dasha party

WELCOME TO CALIFORNIA!

Organizers and Conveners

U.S.A.: Elizabeth Miller, Jeremy Hourigan, David Stone, Jaime Toro, Kaz Fujita, Paul Layer

Russia: Slava Akinin, Boris Natalin, Andrei Prokopiev, Sergei Sokolov, Alexander Khanchuk, Pavel Minyuik

Workshop Mandates: · Share knowledge about a part of the earth whose geologic evolution is still poorly known· Explore mutual scientific goals and set research priorities· Energize a series of plans for attaining these goals

NE Russia

U.S.

NE Russia and N.A. share:

·A linked geologic and plate tectonic history whose details are critical for understanding evolution of our continents and the settingfor our natural resources. ·Pacific plate margin · active subduction · ore deposits, hydrocarbons ·earthquake and volcanic hazards· Arctic margin ·vast poorly known continental shelves ·hydrocarbon potential

(base map from Nokleberg et al. 1998)

Overview Presentations: Dec. 9, 2004What do we know?

What are the major unsolved tectonic questions?

The plate tectonic framework ofNE Russia: Pacific and Arctic

Perspectives

1. The Pacific View: Warren Nokleberg (U.S. Geological Survey)

2. The Arctic View: Larry Lawver (University of Texas, Austin)

Overview Presentations: Dec. 10, 2004What do we know?

What are the major unsolved tectonic questions?

1. The Arctic Margin: Elizabeth Miller and Boris Natal’in

2. Verkhoyansk-Kolyma Orogenic Belt: Andrei Prokopiev Jaime Toro

3. Pacific Margin: Jeremy Hourigan, Alexander Khanchuk, Sergey Sokolov4. Magmatic Belts of NE Russia: Slava Akinin and Paul Layer

5. Plate Boundaries, Seismicity and Geophysics: Kaz Fujita, Mikhail Kogan and Vadim Levin

Overview Presentations:

The Arctic Margin of NE Russia:Outstanding Questions fromthe Arctic Ocean Perspective

Elizabeth Miller and Jaime ToroStanford University, Stanford CA

West Virginia University, Morgantown WV

Their report: http://www.geo-prose.com/amerasian/

Conveners* Bernard Coakley, Geophysical Institute - UAF * Steve Forman, University of Illinois - Chicago * Rick Murray, Boston University * John Tarduno, University of Rochester

This meeting follows:

NSF Workshop on the Amerasian Basin and its Margins

held June 8th and 9th 2004, Washington, DC

We were there: Kaz Fujita, Paul Layer, Elizabeth Miller, Jaime Toro, Andrei Zayonchek,

Workshop on the Amerasian Basin and its Margins

•Knowledge of the Arctic Basins is based on the limited record on the continental margins.

•Outpouring of new data from satellites, airplanes, and submarines

Better bathymetry, gravity, and magnetic maps.

•Terrestrial studies new geologic insights.

•New data testable hypotheses about the tectonic, magmatic, and

paleoclimate history of the Amerasian Basin

•Further progress will require international, coordinated field programs (e.g., IPY), including scientific drilling (e.g., IODP).

Their report: http://www.geo-prose.com/amerasian/

IBCAO (2000)

Main bathymetric features of the Arctic

Ocean

IBCAO (2000)

EURASIANBASIN

AMERASIANBASIN

Eurasian Basin: Continuation of mid-Atlantic spreading center (<55Ma)

Amerasian Basin: A more complex and debated origin (~ 135-120 Ma)

IODP-ACEX

http://www.rcom-bremen.de/English/IODP.html

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Jackson (2000)www.cseg.ca/conferences/2000/2000abstracts/316.PDF

www.ecord.org/about/j/533AGUposter.pdf

Where to read about the new results Our knowledge before

now

Late Cretaceous(80 Ma) marine

56 Ma shallow marine

unconformity

RussiaCanada

Eocene (55 Ma) opening of Eurasian Basin

by Gakkel Ridge spreading

How does this rift end and/or propagate into continental crust?

?

500 km of new ocean crust… Where and how is this extension accommodatedthrough geologic time?

Laptev Sea

Federal Institute for Geosciences and Natural Resources (BGR) HannoverSevmorneftegeofizica (SMNG), Murmansk (http://www.bgr.de/)

Rifting in the Laptev Sea: continuation of Gakkel Ridge into Continental Crust

Federal Institute for Geosciences and Natural Resources (BGR) HannoverSevmorneftegeofizica (SMNG), Murmansk (http://www.bgr.de/)

Seismically mapped normal faults don’t account for all the extension

Mackey et al.(unpublishedDraft, 2004)

IBCAO (2000)

EURASIANBASIN

AMERASIANBASIN

LomonosovRidge

Alpha-MendeleevRidge

GakkelRidge

Makarov BasinInterpretation of how the Amerasian

Basin formed affects

interpretations of Lomonosov, Alpha Ridges, Makarov

Basin and Chukchi Cap Chukchi

Cap

IBCAO (2000)

·Alaskan and Canadian margins are well-characterized (seismic and drilling) compared to the East Siberian Shelf about which nearly nothing is known.

·Limited seismic, dredge, shallow core data from the Canada Basin (Grantz et al.,’90,’98)

·Crustal Transects

·Alpha-Mendeleev Ridge and Makarov Basin are controversial

·New IODP-ICEX hole

U.S.G.S. TACT ProjectNSF CD Bering-

ChukchiProject

ACEX Hole

East Siberian Shelf

Canada Basin

Other models proposed for the formation of the Amerasian Basin -none except the rotation model

are viable for Alaska given the geologic and magnetic anomaly constraints

Rifting models for Amerasian Basin summarized by Lawver and Scotese (1990) with specific predictions for rift versus transform origin of marginsand the geologic matches of margins. Base map IBCAO (2000)

AmerasianBasin

EurasianBasin

Alaska

Russia

Canada

LomonosovRidge

Reconstruction of the Arctic at 140 Ma (Lawver et al.2002)

Reconstruction of the Arctic at 120 Ma (Lawver et al. 2002)

Implications: Lomonosov Ridge (LR) is a transform fault, Chukotka came from Canada, S.Anuyi was a large ocean, Alpha Ridge, a younger Cretaceous hot spot track.

Geology: Persits and Ulmishek, (2003), USGS

Aeromagnetic DataAeromagnetic Data: : Glebovsky et al. Glebovsky et al. (2000), Naval (2000), Naval Research LabResearch Lab

Old aeromagnetic data and its interpretations suggested Makarov Basin spreading from 80 Ma to 60 Ma. (Taylor et al., 1981; Vogt et al., 1982)

Seismic velocities suggest continental or thinned continental crust.

Normal fault origin of Lomonosov-Makarov (Sweeney et al., 1982)

The answers to the origin of Canada Basin lie in Arctic Russia:

·Is Chukotka’s stratigraphy like Canada or like somewhere else?

·Is the South Anyui Zone the remnant of an extensive ocean basin? When did it close ? Does the time of deformation fit the model?

·What is NE Arctic Russia’s magmatic history? Is there evidence for a Cretaceous hot spot track?

Take-home comments from the Amerasian Basin NSF workshop: What can we do on land?

1. Compile/study location, extent of Paleozoic and older deformational belts in the circum-Arctic region to establish tie points across the basin to determine the origin of Amerasian Basin.

2. Study sedimentary successions that closely pre- and post-date inferred age of Amerasian Basin opening. Distribution, ages, provenance-do these reflect changing paleogeographies? How?

3. How does continental magmatic history of NE Russia relate geographically to Alpha-Mendeleev Ridge? Can these rocks, their age and geochemistry help constrain its origin?

4. Neotectonics, earthquakes, plate boundaries and global tectonics: How is North Atlantic spreading transferred through Russia? What are plate motion linkages between Atlantic spreading and Pacific subduction?