TY - JOUR
T1 - Trace element and isotopic geochemistry of Cretaceous magmatism in NE Asia
T2 - Spatial zonation, temporal evolution, and tectonic controls
AU - Tikhomirov, Petr L.
AU - Kalinina, Elena A.
AU - Moriguti, Takuya
AU - Makishima, Akio
AU - Kobayashi, Katsura
AU - Nakamura, Eizo
N1 - Funding Information:
The authors thank all members of the Pheasant Memorial Laboratory (ISEI, Misasa, Japan) for their help in the analytical work and for fruitful discussions. V.O. Ispolatov (Barrick Gold Corporation) and J.M. Amato (New Mexico State University) kindly improved English and provided useful suggestions. The authors are grateful to Dima Kamenetsky (University of Tasmania) for a very encouraging review, and to Andrew Kerr (Cardiff University) for responsive and constructive editorial comments. This study was supported by the program “ Center of Excellence for the 21st Century in Japan ”. In 2009–2015, the work by P.T. was partially supported by RFBR (grants 09-05-01197-а , 10-05-00191-a , 13-05-249-a ).
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/11/1
Y1 - 2016/11/1
N2 - Results of a comprehensive geochemical study (major and trace elements, and isotopes of Sr, Nd, Pb, Hf) of Cretaceous volcanic rocks from the Chukotka area in northeastern Russia are presented. Synthesis of available geological and geochronological data suggests diachronous onset of activity of the Okhotsk–Chukotka volcanic belt (OCVB), the largest magmatic province in the region. The OCVB consists of ca. 106 km3 of volcanic rocks. At 106–105 Ma, subduction-related magmatism initiated in the southern and central segments of the OCVB. In the Central and Northern Chukotka areas, where the northern OCVB is exposed, onset of arc magmatism occurred ca. 10 m.y. after extension-related magmatism of the Chaun igneous province at 109–104 Ma. Mafic rocks from the OCVB yield (87Sr/86Sr)80 Ma of 0.7033 to 0.7047, εNd80 Ma of 0.0 to 7.10, εHf80 Ma of 4.12 to 12.88, (206Pb/204Pb)80 Ma of 18.11 to 18.42, and (208Pb/204Pb)80 Ma of 37.96 to 38.21. Volcanic rocks from the Chaun province, as well as OCVB rocks from Northern Chukotka, originate from a relatively enriched source and have (87Sr/86Sr)80 Ma of 0.7088 to 0.7100, εNd80 Ma of − 5.81 to − 3.42, εHf80 Ma of − 3.40 to − 0.25, (206Pb/204Pb)80 Ma of 18.69 to 18.90, and (208Pb/204Pb)80 Ma of 38.65 to 38.86. No definitive across-arc elemental or isotopic zonation of the OCVB has been revealed, probably because of wide-scale crustal melting and subsequent contamination of mantle-derived melts. However, there is a clear along-arc isotopic zonation. In our interpretation, this results from heterogeneity of the subcontinental lithospheric mantle, which likely was a major contributor to the magma source. The similar isotopic signatures of silicic (dominantly crust-derived) and mafic (mantle-derived) volcanic rocks in each OCVB segment imply that remelting of juvenile mafic underplated material was the main process responsible for the crust-derived magma generation. These data from the major Cretaceous magmatic provinces of northeast Asia are synthesized in context of existing plate tectonic reconstructions.
AB - Results of a comprehensive geochemical study (major and trace elements, and isotopes of Sr, Nd, Pb, Hf) of Cretaceous volcanic rocks from the Chukotka area in northeastern Russia are presented. Synthesis of available geological and geochronological data suggests diachronous onset of activity of the Okhotsk–Chukotka volcanic belt (OCVB), the largest magmatic province in the region. The OCVB consists of ca. 106 km3 of volcanic rocks. At 106–105 Ma, subduction-related magmatism initiated in the southern and central segments of the OCVB. In the Central and Northern Chukotka areas, where the northern OCVB is exposed, onset of arc magmatism occurred ca. 10 m.y. after extension-related magmatism of the Chaun igneous province at 109–104 Ma. Mafic rocks from the OCVB yield (87Sr/86Sr)80 Ma of 0.7033 to 0.7047, εNd80 Ma of 0.0 to 7.10, εHf80 Ma of 4.12 to 12.88, (206Pb/204Pb)80 Ma of 18.11 to 18.42, and (208Pb/204Pb)80 Ma of 37.96 to 38.21. Volcanic rocks from the Chaun province, as well as OCVB rocks from Northern Chukotka, originate from a relatively enriched source and have (87Sr/86Sr)80 Ma of 0.7088 to 0.7100, εNd80 Ma of − 5.81 to − 3.42, εHf80 Ma of − 3.40 to − 0.25, (206Pb/204Pb)80 Ma of 18.69 to 18.90, and (208Pb/204Pb)80 Ma of 38.65 to 38.86. No definitive across-arc elemental or isotopic zonation of the OCVB has been revealed, probably because of wide-scale crustal melting and subsequent contamination of mantle-derived melts. However, there is a clear along-arc isotopic zonation. In our interpretation, this results from heterogeneity of the subcontinental lithospheric mantle, which likely was a major contributor to the magma source. The similar isotopic signatures of silicic (dominantly crust-derived) and mafic (mantle-derived) volcanic rocks in each OCVB segment imply that remelting of juvenile mafic underplated material was the main process responsible for the crust-derived magma generation. These data from the major Cretaceous magmatic provinces of northeast Asia are synthesized in context of existing plate tectonic reconstructions.
KW - Cretaceous magmatism
KW - Isotope geochemistry
KW - Mantle heterogeneity
KW - Northeastern Russia
KW - Paleotectonics
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U2 - 10.1016/j.lithos.2016.08.009
DO - 10.1016/j.lithos.2016.08.009
M3 - Article
AN - SCOPUS:84989347287
VL - 264
SP - 453
EP - 471
JO - Lithos
JF - Lithos
SN - 0024-4937
ER -