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Land-Ocean Systems in the Siberian Arctic: Dynamics and History
in the western part of the East Siberian Sea by Russian and German research institutes
(Sekretov, 1993a; Drachev et aI., 1995b; Roeser et aI., 1995). In this paper we present our
hypothesis on the structure of the eastern Russian Arctic continental margin (ERAM) and its
relationship to the evolution of the Arctic oceanic basins, based on combining of the recently
obtained satellite altimeter gravity data with the results of the offshore MCS surveys.
Tectonic setting
The ERAM occupies an area where the Siberian Craton, Early Mesozoic Taimyr Fold Belt, and
Late Mesozoic New Siberian-Chukchi and Verkhoyansk-Kolyma fold belts come together
(Figure 1). The latter two are divided by the narrow and highly deformed Lyakhov-South
Anyui ophiolitic suture which has been suggested by Savostin et al. (1984b), Parfenov and
Natal'in (1986), Drachev and Savostin (1993) to be a zone of collision between northeastern
edge of the Laurasia supercontinent and New Siberian-Chukchi microplate in the mid
Cretaceous time. The deformed Paleozoic and Mesozoic complexes of these large tectonic
elements form a poorly known heterogeneous basement overlain everywhere with a sharp
angular unconformity by almost undeformed clastic sequences of Late Cretaceous to Cenozoic
in age. These sequences fill the extensive offshore sedimentary basins which are believed to be
initially originated by rifting and post-rift thermal subsidence during the opening of the Arctic
oceanic basins. The Laptev Sea rifts reveal a strong link to sea-floor spreading axis (Gakkel
Ridge) in the Eurasia Basin (Grachev, 1982; Drachev et a!., 1995a; Roeser et a!., 1995). The
kinematics of the opening of this basin is well understood because it contains a readily
decipherable sea-floor magnetic pattern suggesting that sea-floor spreading may have begun as
early as 54-64 Ma (Karasik, 1968; Karasik et a!., 1983; Kovacs et a!., 1983; Savostin et a!.,
1984a). The poorly studied rifts of the East Siberian Sea and northwestern part of the Chukchi
Sea probably originated in the similar tectonic conditions in response to earlier spreading
episodes in the Amerasia Basin.
Satellite derived altimeter data
Satellite radar altimetry is the means to derive marine gravity field through accurate
measurement of the average sea surface topography. The ERS-l satellite, launched in 1991,
provided the first altimetric observations of the Arctic Ocean to latitudes of 82° N.
However the ERAM suffers coverage by both seasonal and, in some areas, permanent sea ice
cover. Satellite altimeter data over sea ice areas are normally excluded from global marine
gravity fields as the onboard estimates of surface height suffer greatly increased noise due to
changes in the return echo waveform (Laxon, 1994). To overcome this problem, techniques
have been developed to reprocess the individual return echoes in order to significantly reduce
noise and allow marine gravity anomalies to be extracted in the usual manner (McAdoo and
Marks, 1992). This process was used to derive the first satellite marine gravity field of the
Arctic Ocean from a single 35-day repeat cycle of ERS-l giving an unprecedented view of its
tectonic fabric (Laxon and McAdoo, 1994).
The gravity field presented in this paper supplants that first Arctic field. This new, higher
resolution field is derived from much more data including data from the ERS-l geodetic
mission whose a 168-day repeat cycle yielded a dense grid of observations with a spacing of
less than 4 km at altitudes above 60° N. The resolution of this new gravity field, estimated by
comparisons with airborne gravity data, is approximately 30-35 km (Lax on and McAdoo,
1998).
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
in the western part of the East Siberian Sea by Russian and German research institutes
(Sekretov, 1993a; Drachev et aI., 1995b; Roeser et aI., 1995). In this paper we present our
hypothesis on the structure of the eastern Russian Arctic continental margin (ERAM) and its
relationship to the evolution of the Arctic oceanic basins, based on combining of the recently
obtained satellite altimeter gravity data with the results of the offshore MCS surveys.
Tectonic setting
The ERAM occupies an area where the Siberian Craton, Early Mesozoic Taimyr Fold Belt, and
Late Mesozoic New Siberian-Chukchi and Verkhoyansk-Kolyma fold belts come together
(Figure 1). The latter two are divided by the narrow and highly deformed Lyakhov-South
Anyui ophiolitic suture which has been suggested by Savostin et al. (1984b), Parfenov and
Natal'in (1986), Drachev and Savostin (1993) to be a zone of collision between northeastern
edge of the Laurasia supercontinent and New Siberian-Chukchi microplate in the mid
Cretaceous time. The deformed Paleozoic and Mesozoic complexes of these large tectonic
elements form a poorly known heterogeneous basement overlain everywhere with a sharp
angular unconformity by almost undeformed clastic sequences of Late Cretaceous to Cenozoic
in age. These sequences fill the extensive offshore sedimentary basins which are believed to be
initially originated by rifting and post-rift thermal subsidence during the opening of the Arctic
oceanic basins. The Laptev Sea rifts reveal a strong link to sea-floor spreading axis (Gakkel
Ridge) in the Eurasia Basin (Grachev, 1982; Drachev et a!., 1995a; Roeser et a!., 1995). The
kinematics of the opening of this basin is well understood because it contains a readily
decipherable sea-floor magnetic pattern suggesting that sea-floor spreading may have begun as
early as 54-64 Ma (Karasik, 1968; Karasik et a!., 1983; Kovacs et a!., 1983; Savostin et a!.,
1984a). The poorly studied rifts of the East Siberian Sea and northwestern part of the Chukchi
Sea probably originated in the similar tectonic conditions in response to earlier spreading
episodes in the Amerasia Basin.
Satellite derived altimeter data
Satellite radar altimetry is the means to derive marine gravity field through accurate
measurement of the average sea surface topography. The ERS-l satellite, launched in 1991,
provided the first altimetric observations of the Arctic Ocean to latitudes of 82° N.
However the ERAM suffers coverage by both seasonal and, in some areas, permanent sea ice
cover. Satellite altimeter data over sea ice areas are normally excluded from global marine
gravity fields as the onboard estimates of surface height suffer greatly increased noise due to
changes in the return echo waveform (Laxon, 1994). To overcome this problem, techniques
have been developed to reprocess the individual return echoes in order to significantly reduce
noise and allow marine gravity anomalies to be extracted in the usual manner (McAdoo and
Marks, 1992). This process was used to derive the first satellite marine gravity field of the
Arctic Ocean from a single 35-day repeat cycle of ERS-l giving an unprecedented view of its
tectonic fabric (Laxon and McAdoo, 1994).
The gravity field presented in this paper supplants that first Arctic field. This new, higher
resolution field is derived from much more data including data from the ERS-l geodetic
mission whose a 168-day repeat cycle yielded a dense grid of observations with a spacing of
less than 4 km at altitudes above 60° N. The resolution of this new gravity field, estimated by
comparisons with airborne gravity data, is approximately 30-35 km (Lax on and McAdoo,
1998).