Provenance Change in Cretaceous–Paleogene Fore-arc in Western Hokkaido: U–Pb Dating of Detrital Zircons from the Yezo Group

Abstract

To reconstruct the tectono-sedimentary history of the CretaceousPaleogene arc-trench system in western Hokkaido, UPb ages were measured of detrital zircons in 11 Cretaceous and Paleogene fore-arc sandstones of the Yezo Group in the Oyubari and Mikasa areas. Age spectra of dated zircons demonstrate that Aptian sandstones of the basal Yezo Group are characterized by the dominant occurrence of Early Cretaceous grains with small amounts of Jurassic, Triassic, Permian, and Precambrian grains (Type 1) . In contrast, those of Cenomanian to Paleocene sand stones of the middle to upper Yezo Group are dominated almost totally by mid-to Late Cretaceous grains (Type 2) . This remarkable change from Type 1 to Type 2 occurred irreversibly during the Albian, indicating that the surface crust in the provenance in western Hokkaido was significantly renewed then. Among nine sandstones of Type 2, a positive correlation exists between zircon peak age and stratigraphic age, suggesting the unidirectional/gradual replacement of exposed magmatic rocks in the provenance, in particular, new volcanics/intrusives (RebunKabato belt to the west) . The pre-Cretaceous zircons in Type 1 sandstones were probably recycled from sand stones in the Jurassic accretionary complexes of the Oshima belt to the west. The coeval and identical turnover in zircon age spectra of the Cretaceous fore-arc sandstones recognized in Southwest Japan, from Kyushu to Kanto district, suggests that the fore-arc basin and its provenance with monotonous arc crustal rocks have ubiquitously developed along the Cretaceous East Asian margin over more than 1,500 km before the Miocene opening of the Japan Sea.

The Origin of the Paleo‐Kuril Arc, NE Japan: Sediment Provenance Change and Its Implications for Plate Configuration in the NW Pacific Region Since the Late Cretaceous

“…The Nemuro Group is forearc deposits of the magmatic arc, and therefore, it is natural that the Jurassic to the Late Cretaceous age peaks of detrital zircons were also sourced from the local magmatic region. In most areas in the East Asia regions such as Sakhalin (Zhao et al., 2017b), Sikhote‐Alin (Nadanhada Terrane; Zhou et al., 2014), South Korean (Choi et al., 2016), North Korean (Choi et al., 2016), Kamchatka (Sredinny Massif; Bindeman et al., 2002), SW Japan (Aoki et al., 2012), and NE Japan (Ishizaka et al., 2021), predominant zircon ages range from the Early Jurassic to the Late Cretaceous (Figure 10). Thus, this period is characterized by intense magmatic activity as well as metamorphism.…”

Discovery of Early Paleocene (Danian) tuff from the Yezo Group in the Yubari area, Hokkaido, Northeast Japan

“…In the Oyubari area, however, previous studies have only provided detrital zircon U-Pb dates from a sandstone sample in the upper part of the Hakobuchi Formation (Ishizaka et al, 2021). Ishizaka et al (2021) reported a maximum depositional age of 64.3 ± 1.1 Ma (the YC1σ age of Dickinson and Gehrels, 2009), with the youngest single grain age (YSG) of 61.8 ± 2.2 Ma (Danian to Selandian, Paleocene). The results of Ishizaka et al (2021) imply the possible presence of a Lower Paleocene section in the Hakobuchi Formation.…”

“…Ishizaka et al (2021) reported a maximum depositional age of 64.3 ± 1.1 Ma (the YC1σ age of Dickinson and Gehrels, 2009), with the youngest single grain age (YSG) of 61.8 ± 2.2 Ma (Danian to Selandian, Paleocene). The results of Ishizaka et al (2021) imply the possible presence of a Lower Paleocene section in the Hakobuchi Formation.…”