Download Miller NE Russia Workshop ppt v.2

U.S.-Russia Joint Workshop on the
Plate Tectonic Evolution of NE Russia
Stanford University Dec. 9-12, 2004
Sponsored by the
U.S. National Science Foundation
(Tectonics and International Divisions)
with travel support for Russian scientists shared by
Placer Dome, Shell International, Anadarko(?), Encana, Exxon,
Pacific Rim Geology Consultants
for
Fall 2004 AGU Special Session in honor of Leonid Parfenov
San Francisco, CA, Dec. 16th
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.
Russia and N.America share:
·A linked geologic and
plate tectonic history whose
details are critical for
understanding our natural
resources.
·Pacific plate margin
· active subduction
·earthquake and volcanic
hazzards
· ore deposits, hydrocarbons
(Nokleberg et al. 1998)
· Arctic margin
·vast poorly known
continental shelves
·hydrocarbon potential
Overview Presentations:
What 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 Sokolov
4. 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:
What do we know and what are the major
unsolved questions about the geology and tectonics
of North East Russia and adjacent North America?
The Arctic Margin of NE Russia:
Outstanding Questions and Problems from
the Arctic Ocean Perspective
Elizabeth Miller
Stanford University, Stanford CA
This meeting follows:
A NSF Workshop on the Amerasian Basin and its
Margins
June 8th and 9th 2004, Washington, DC
Conveners
*
Bernard Coakley, Geophysical Institute - UAF
*
Steve Forman, University of Illinois - Chicago
*
Rick Murray, Boston University
*
John Tarduno, University of Rochester
We were there: Kaz Fujita, Paul Layer, Elizabeth Miller, Jaime Toro,
Andrei Zayonchek,
Their report: http://www.geo-prose.com/amerasian/
Workshop on the Amerasian Basin and its Margins
Our incomplete knowledge of the history of the Amerasian Basin and the
Arctic has been inferred from the limited stratigraphic record exposed on the
Canadian and American continental margins. During the last few years an
outpouring of data collected in the Arctic Ocean basin from satellites,
airplanes and submarines has been made available and compiled into
revised and much-improved maps and grids of bathymetry, gravity anomalies
and magnetic anomalies. Terrestrial studies on the adjacent margins in
Eurasia and North American have yielded new geologic insights. With these
new data, it is now possible to formulate 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/
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  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/
Main
bathymetric
features of
the Arctic
Ocean
IBCAO (2000)
EURASIAN
BASIN
Eurasian Basin:
Continuation of
mid-Atlantic
spreading center
(<55 Ma )
Amerasian Basin:
A more complex
and debated origin
(~ 135-120 Ma)
AMERASIAN
BASIN
IBCAO (2000)
Alpha-Mendeleev
Ridge
Makarov Basin
Chukchi
Platform
AMERASIAN
BASIN
Interpretation of
how the Amerasian
Basin formed
affects
interpretations of
Lomonosov, Alpha
Ridges, Makarov
Basin and Chukchi
Platform
EURASIAN
BASIN
Lomonosov Gakkel
Ridge
Ridge
IBCAO (2000)
Limited seismic data
from the Amerasian
Basin
Only ONE drillhole
Alaskan and Canadian
margins are wellcharacterized (seismic
and drilling) compared
to the East Siberian
Shelf about which
nearly nothing is
known.
U.S.G.S.
TACT
Project
NSF CD
BeringChukchi
Project
ICEX
Hole
IBCAO (200
Aeromagnetic Data:
Glebovsky et al. (2000),
Naval Research Lab
Geology: Persits and
Ulmishek, (2003), USGS
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.
Amerasian
Basin
Lomonosov
Ridge
Canada
Eurasian
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 margins
and the geologic matches of margins. Base map IBCAO (2000)
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 (recent refs.)
Normal fault origin of
the Lomonosov Ridge
(Sweeney et al., 1982)
The answers to these questions lie in the geology of 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?
Canada
Russia
?
Eocene (55 Ma)
opening of Eurasian Basin
by Gakkel Ridge spreading
Outstanding problems also exist with
the younger geology of NE Russia
Main Question: What exactly happens to
this oceanic rift in continental crust?
500 km of new ocean crust… Where
and how is this extension accommodated
through geologic time?
Rifting in the Laptev Sea: continuation of Gakkel Ridge into Continental Crust
Federal Institute for Geosciences and Natural Resources (BGR) Hannover
Sevmorneftegeofizica (SMNG), Murmansk (http://www.bgr.de/)
Seismically mapped normal faults don’t account for all the extension
Federal Institute for Geosciences and Natural Resources (BGR) Hannover
Sevmorneftegeofizica (SMNG), Murmansk (http://www.bgr.de/)
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. 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?
3. Study sedimentary successions that closely pre- and post-date inferred
age of Amerasian Basin opening. Distribution, ages, provenance-do
these reflect changing paleogeographies? How?
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