New data on the composition of ophiolites from the Kumroch-Valagin segment of the Achayvayam-Valagin paleoarc (Eastern Kamchatka)

Tsukanov, N. V.; Сколотнев, С. Г.; Peyve, A. A.

doi:10.1134/s1028334x09060105

Cited by 2 publications

(6 citation statements)

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“…Ophiolites associated with the Olyutorsky arc are found in different localities in eastern Kamchatka. Upper Cretaceous peridotites, gabbros, and diabases belonging to a coherent ophiolite complex are exposed within a serpentite mélange in the Kumroch Range (Tsukanov et al, ). A well‐preserved ophiolite sequence from Karaginsky Island yielded U‐Pb (SHRIMP) zircon ages of ~76–72 Ma (Campanian; Tararin et al, ).…”

Section: Reviewmentioning

confidence: 99%

“…A Late Cretaceous age of formation of ~100–70 Ma was also obtained for the ophiolitic gabbros and peridotites in eastern Kamchatka (Tararin et al, ). Based on their geochemical signature, the ophiolites of the Kumroch Range and Karaginsky Island are interpreted to have formed in a suprasubduction zone setting (Kravchenko‐Berezhnoy & Nazimova, ; Skolotnev et al, ; Tsukanov et al, ).…”

Section: Reviewmentioning

confidence: 99%

“…Following the scenarios of Maffione et al () and van Hinsbergen et al (), we model that the original Izanagi‐Pacific ridge, preserved in the forearc above the nascent southward intraoceanic subduction zone, was reactivated and became the Pacific‐Olyutorsky plate boundary. The geochemical signatures predicted by such a scenario are found in the suprasubduction zone signature of Upper Cretaceous ophiolites associated with the Olyutorsky arc (Geist et al, ; Kravchenko‐Berezhnoy & Nazimova, ; Tsukanov et al, ) and the presence of Paleocene‐Upper Eocene MORB‐lavas of the Vetlovsky‐Govena terrane in the accretionary prism below the Olyutorsky arc nappes in Kamchatka (Bakhteev et al, ; Gladenkov, ; Zinkevich & Tsukanov, ) is straightforwardly explained by a spreading center between the Olyutorsky arc and the Pacific plate. In this scenario, the Olyutorsky‐Pacific ridge likely became active shortly after subduction initiation at ~85 Ma, and we therefore estimate that seafloor spreading south (east) of the Olyutorsky arc occurred between ~85 and 60–50 Ma.…”

Section: Reconstruction Of Nw Pacific Active Marginsmentioning

confidence: 99%

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Reconstruction of Subduction and Back‐Arc Spreading in the NW Pacific and Aleutian Basin: Clues to Causes of Cretaceous and Eocene Plate Reorganizations

2019

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The Eocene (~50–45 Ma) major absolute plate motion change of the Pacific plate forming the Hawaii‐Emperor bend is thought to result from inception of Pacific plate subduction along one of its modern western trenches. Subduction is suggested to have started either spontaneously, or result from subduction of the Izanagi‐Pacific mid‐ocean ridge, or from subduction polarity reversal after collision of the Olyutorsky arc that was built on the Pacific plate with NE Asia. Here we provide a detailed plate‐kinematic reconstruction of back‐arc basins and accreted terranes in the northwest Pacific region, from Japan to the Bering Sea, since the Late Cretaceous. We present a new tectonic reconstruction of the intraoceanic Olyutorsky and Kronotsky arcs, which formed above two adjacent, oppositely dipping subduction zones at ~85 Ma within the north Pacific region, during another Pacific‐wide plate reorganization. We use our reconstruction to explain the formation of the submarine Shirshov and Bowers Ridges and show that if marine magnetic anomalies reported from the Aleutian Basin represent magnetic polarity reversals, its crust most likely formed in an ~85‐ to 60‐Ma back‐arc basin behind the Olyutorsky arc. The Olyutorsky arc was then separated from the Pacific plate by a spreading ridge, so that the ~55‐ to 50‐Ma subduction polarity reversal that followed upon Olyutorsky‐NE Asia collision initiated subduction of a plate that was not the Pacific. Hence, this polarity reversal may not be a straightforward driver of the Eocene Pacific plate motion change, whose causes remain enigmatic.

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Section: Reviewmentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

Section: Reconstruction Of Nw Pacific Active Marginsmentioning

confidence: 99%

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Reconstruction of Subduction and Back‐Arc Spreading in the NW Pacific and Aleutian Basin: Clues to Causes of Cretaceous and Eocene Plate Reorganizations

2019

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“…A Late Cretaceous age of formation of ~100-70 Ma was also obtained for the ophiolitic gabbros and peridotites in eastern Kamchatka (Tararin et al, 2012). Based on their geochemical signature, the ophiolites of the Kumroch Range and Karaginsky Island are interpreted to have formed in a suprasubduction zone setting (Kravchenko-Berezhnoy & Nazimova, 1991;Skolotnev et al, 2018;Tsukanov et al, 2009).…”

Section: Kamchatkamentioning

confidence: 96%

“…Ophiolites associated with the Olyutorsky arc are found in different localities in eastern Kamchatka. Upper Cretaceous peridotites, gabbros, and diabases belonging to a coherent ophiolite complex are exposed within a serpentite mélange in the Kumroch Range (Tsukanov et al, 2009). A well-preserved ophiolite sequence from Karaginsky Island yielded U-Pb (SHRIMP) zircon ages of ~76-72 Ma (Campanian; Tararin et al, 2012).…”

Section: Kamchatkamentioning

confidence: 99%

On pole position

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Paleomagnetism provides the only quantitative tool to reconstruct the position and motion of tectonic plates and continents in deep geological time. These reconstructions often rely on apparent polar wander paths (APWPs), which describe the past position and motion of plates relative to the Earth’s spin axis. In addition to providing a paleomagnetic reference frame for paleogeography, these paths serve to quantify relative tectonic displacements with other lithospheric blocks. A long-discussed problem is that conventional approaches to computing polar wander do not propagate key sources of uncertainty in the underlying data, such as data scatter or age uncertainty, but proposed solutions remained mostly qualitative. Recently, this problem became more urgent: Rowley (2019, Tectonics) showed that as much as 50% of the data that underlie the currently most widely used global APWP are statistically significantly displaced relative to that APWP. This implies that the resolution at which a geologically meaningful statistical difference between a paleomagnetic dataset and an APWP may be determined, is strongly limited, which undermines the current tectonic and paleogeographic applications of paleomagnetism. This thesis aims to examine the causes of dispersion of paleomagnetic data behind APWPs and to build a global APWP in which key data uncertainties are propagated, such that it may be used to determine geologically meaningful relative displacements. We show that the uncertainty of APWPs computed from paleomagnetic poles, which is the current standard, is mostly determined by the arbitrary choice of how many datapoints are used per pole. This thesis then develops a novel approach in which apparent polar wander paths are computed from site-level paleomagnetic data instead of paleomagnetic poles. In this approach, larger weight is assigned to larger datasets and temporal and spatial uncertainties in the paleomagnetic data are incorporated. We present a global apparent polar wander path for the last 320 Ma using the new statistical approach proposed in this thesis, as well as using a fully updated paleomagnetic database. We find that the first-order geometry of this path is similar to previous models but with smaller uncertainties. Moreover, we show that correcting for temporal bias in the paleomagnetic data allows improved quantification of polar wander rates, and that previously observed peaks in polar wander likely resulted from such bias. We introduce the open-source web application APWP-online.org that provides user-friendly tools to compute apparent polar wander paths using our new methodology as well as the computation of relative paleomagnetic displacements. The website also hosts a community platform for the continuous improvement of the path in the future through the addition of new high-quality paleomagnetic data. Finally, we provide new quantitative estimates of true polar wander during the last 320 Ma by comparing our new global apparent polar wander path with existing mantle reference frames. The computed true polar wander paths suggest that the true polar wander rotations occurred about two roughly orthogonal axes in the equatorial plane. We discuss the geodynamic implications of these findings and highlight future opportunities for the identification and quantification of true polar wander on geological timescales.

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New data on the composition of ophiolites from the Kumroch-Valagin segment of the Achayvayam-Valagin paleoarc (Eastern Kamchatka)

Cited by 2 publications

References 2 publications

Reconstruction of Subduction and Back‐Arc Spreading in the NW Pacific and Aleutian Basin: Clues to Causes of Cretaceous and Eocene Plate Reorganizations

Reconstruction of Subduction and Back‐Arc Spreading in the NW Pacific and Aleutian Basin: Clues to Causes of Cretaceous and Eocene Plate Reorganizations

On pole position

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