Tectonic subsidence of the Lomonosov Ridge

Minakov, Alexander; Podladchikov, Y. Y.

doi:10.1130/g32445.1

Cited by 16 publications

(19 citation statements)

References 25 publications

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“…This hiatus is regarded to mark the transition from poorly oxygenated to fully oxygenated ("ventilated") conditions in the Arctic Ocean completed by 17.5 Ma [Jakobsson et al, 2007]. As well, during the same time the Lomonosov Ridge was close to sea level as revealed by various shallow-water clays detected in the drilling samples [Moran et al, 2006;Sangiorgi et al, 2008]. At this depth the ridge was probably exposed to repeated erosion and deposition, also because a strong regression in sea level occurred at about 28 Ma in the Oligocene, followed by some smaller rises and falls [Haq et al, 1988;Hegewald and Jokat, 2013].…”

Section: Origin Of the Distinct High-amplitude Reflector Sequence (Hars)mentioning

confidence: 92%

“…In the middle Miocene the deep water connection through the Fram Strait to the North Atlantic was completed and the modern current system established in the Arctic Basin [Jakobsson et al, 2007]. The Lomonosov Ridge subsided well below sea level, and pelagic deposition conditions started to prevail [Moran et al, 2006]. This depositional regime is expressed in the transparent and uniform reflection pattern with low reflection amplitudes of units MB 4 and MB 5, indicating only minor changes in the deposition regime.…”

Section: Origin Of the Distinct High-amplitude Reflector Sequence (Hars)mentioning

confidence: 99%

“…Drilling data acquired on the central Lomonosov Ridge by the Arctic Coring Expedition (ACEX) in 2004 confirmed the Cenozoic age of the sedimentary units on top of the Ridge [ Backmann et al , ; Moran et al , ; Jakobsson et al , ]. Surprisingly, a large hiatus spanning from 44 to 18 Ma was found [ Moran et al , ], which suggests that the Ridge may have subsided below sea level in earliest Eocene but remained in shallow‐water depth until Miocene [ Sangiorgi et al , ; Minakov and Podladchikov , ]. Alternatively, the hiatus may be a consequence of a pronounced sea level fall during this time [ Hegewald and Jokat , ] and/or strong erosive currents [ Jokat et al , ].…”

Section: Regional Settingmentioning

confidence: 99%

“…Langinen et al [2009] describe this regional angular discordance as the Lomonosov Unconformity (LU). Drilling data acquired on the central Lomonosov Ridge by the Arctic Coring Expedition (ACEX) in 2004 confirmed the Cenozoic age of the sedimentary units on top of the Ridge [Backmann et al, 2008;Moran et al, 2006;Jakobsson et al, 2007]. Surprisingly, a large hiatus spanning from 44 to 18 Ma was found [Moran et al, 2006], which suggests that the Ridge may have subsided below sea level in earliest Eocene but remained in shallow-water depth until Miocene [Sangiorgi et al, 2008;Minakov and Podladchikov, 2012].…”

Section: Introductionmentioning

confidence: 96%

“…These provide an insight into the sedimentary cover and crustal fabric of the ridge and the adjacent Laptev Sea. Drill site data of the US Chukchi Sea [Sherwood et al, 2002], the Lomonosov Ridge (ACEX) [Jakobsson et al, 2007;Moran et al, 2006], and results from onshore investigations on the New Siberian Islands [Franke et al, 2001[Franke et al, , 2004Kos'ko and Korago, 2009] are incorporated. Linking these data sets provides a more consistent seismostratigraphic model which (1) constraints the sedimentation history along the East Siberian margin and (2) provides a framework for future scientific drilling on the Lomonosov Ridge.…”

Section: Introductionmentioning

confidence: 99%

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Seismostratigraphy of the Siberian Sector of the Arctic Ocean and adjacent Laptev Sea Shelf

2014

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A new seismostratigraphic model has been established within the Arctic Ocean adjacent to the East Siberian Shelf on the basis of multichannel seismic reflection data acquired along a transect at 81°N. Ages for the sedimentary units were estimated via links to seismic lines and drill site data of the US Chukchi Shelf, the Lomonosov Ridge, and the adjacent Laptev Shelf. Two distinct seismic units were mapped throughout the area and are the constraints for dating the remaining strata. The lower marker unit, a pronounced high-amplitude reflector sequence (HARS), is the most striking stratigraphic feature over large parts of the Arctic Ocean. It indicates a strong and widespread change in deposition conditions. Probably, it developed during Oligocene times when a reorientation of Arctic Plates took place, accompanied by the gradual opening of the Fram Strait, and a widespread regression of sea level. The top of the HARS likely marks the end of Oligocene/early Miocene (23 Ma). An age estimate for the base of the sequence is less clear but likely corresponds to base of Eocene (˜56 Ma). The second marked unit detected on the seismic lines parallels the seafloor with a thickness of about 200 ms two-way travel time (160 m). Its base is marked by a change from a partly transparent sequence with weak amplitude reflections below to a set of continuous high-amplitude reflectors above. This interface likely marks the transition to large-scale glaciation of the northern hemisphere and therefore is ascribed to the top Miocene (5.3 Ma).

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Section: Origin Of the Distinct High-amplitude Reflector Sequence (Hars)mentioning

confidence: 92%

Section: Origin Of the Distinct High-amplitude Reflector Sequence (Hars)mentioning

confidence: 99%

Section: Regional Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Seismostratigraphy of the Siberian Sector of the Arctic Ocean and adjacent Laptev Sea Shelf

2014

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Circum‐Arctic mantle structure and long‐wavelength topography since the Jurassic

et al. 2014

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The circum-Arctic is one of the most tectonically complex regions of the world, shaped by a history of ocean basin opening and closure since the Early Jurassic. The region is characterized by contemporaneous large-scale Cenozoic exhumation extending from Alaska to the Atlantic, but its driving force is unknown. We show that the mantle flow associated with subducted slabs of the South Anuyi, Mongol-Okhotsk, and Panthalassa oceans have imparted long-wavelength deflection on overriding plates. We identify the Jurassic-Cretaceous South Anuyi slab under present-day Greenland in seismic tomography and numerical mantle flow models. Under North America, we propose the "Farallon" slab results from Andean-style ocean-continent convergence around~30°N and from a combination of ocean-continent and intraoceanic subduction north of 50°N. We compute circum-Arctic dynamic topography through time from subduction-driven convection models and find that slabs have imparted on average <1-16 m/Myr of dynamic subsidence across the region from at least 170 Ma to~50 Ma. With the exception of Siberia, the main phase of circum-Arctic dynamic subsidence has been followed either by slowed subsidence or by uplift of <1-6 m/Myr on average to present day. Comparing these results to geological inferences suggest that subduction-driven dynamic topography can account for rapid Middle to Late Jurassic subsidence in the Slave Craton and North Slope (respectively, <15 and 21 m/Myr, between 170 and 130 Ma) and for dynamic subsidence (<7 m/Myr, 170-50 Ma) followed by dynamic uplift (<6 m/Myr since 50 Ma) of the Barents Sea region. Combining detailed kinematic reconstructions with geodynamic modeling and key geological observations constitutes a powerful tool to investigate the origin of vertical motion in remote regions.

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