Heterogeneous distribution of uranium within zircon grains: Implications for fission-track dating.

和博, 鈴木

doi:10.5575/geosoc.94.1

Cited by 19 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All other zircons with a non-transparent or milky appearance of the whole crystal or chip were found to be transparent after preparation of thin platelets. Another point that must be considered here is the strong volume expansion of zircon during metamictization (Murakami and others, 1991): Zircons with heterogeneous distribution of U and Th (see, for example, Sommerauer, 1976;Sahama, 1981;Suzuki, 1988) may be heterogeneously metamict (Smith and others, 1991;Nasdala, Pidgeon, and Wolf, 1996;Nasdala and others, 1998). Heterogeneous metamictization, however, causes heterogeneous expansion leading to local stress and often to the formation of micro-fissures and cracks (Chakoumakos and others, 1987;Lee and Tromp, 1995).…”

Section: Samples and Preparationmentioning

confidence: 99%

The incorporation of hydroxyl groups and molecular water in natural zircon (ZrSiO4)

Nasdala¹

2001

American Journal of Science

View full text Add to dashboard Cite

Section: Samples and Preparationmentioning

confidence: 99%

The incorporation of hydroxyl groups and molecular water in natural zircon (ZrSiO4)

Nasdala¹

2001

American Journal of Science

View full text Add to dashboard Cite

“…In the case of underestimation, apparent ages become older than the true ages, and vice versa. The second is external effects of uranium outside or near the external surfaces of zircon grains, which mean contamination of fission-tracks originated from adjacent grains outside or enrichment of uranium along the external surfaces of the grains (Suzuki, 1988;Danhara et al, 1991). Because we used the external surfaces for the FT analysis, such effects might lead to older FT ages than the true ages.…”

mentioning

confidence: 99%

LA-ICP-MS U–Pb and fission-track ages of felsic tuff beds of the Takikubo Formation, Izumi Group in the Kan-onji district, eastern Shikoku, southwestern Japan

Noda

Danhara²,

Iwano³

et al. 2017

Bull. Geol. Surv. Japan

View full text Add to dashboard Cite

LA-ICP-MS U-Pb and fission-track (FT) dating were performed for detrital zircons in two felsic tuff samples (KT01 and KT02) in order to estimate the depositional age of the Takikubo Formation (Izumi Group) in the Kan-onji district, eastern Shikoku, southwestern Japan. Total 30 grains analyzed for each sample indicated that the U-Pb ages composed of multiple populations chiefly of younger (75-85 Ma) and older (85-95 Ma) clusters. The concordia ages calculated by grains in the younger clusters were 78.3±0.5 Ma (2σ) for KT01 (number of accepted grains n = 23) and 80.8±0.7 Ma (2σ) for KT02 (n = 9). The U-Pb ages of KT01 are comparable with 79±7 Ma (2σ) of the FT age from the same sample. The U-Pb ages of KT01 could constrain the maximum depositional age near the basal part of the Takikubo Formation, which was middle of the Middle Campanian (polarity chron C33n in the magnetostratigraphy).Keywords: Campanian, Cretaceous, Felsic tuff, Fission-track age, Izumi Group, Shikoku, Takikubo Formation, U-Pb age IntroductionThe Izumi Group is forearc basin deposits of the Late Cretaceous, which is narrowly distributed from western Shikoku to the Kii Peninsula along the northern side of the Median Tectonic Line. Macro-fossils (ammonoids and inoceramids) and micro-fossils (radiolarian assemblages) show that the depositional age of the Izumi Group are Campanian to Maastrichtian, Late Cretaceous (Suyari, 1973;Bando and Hashimoto, 1984;Yamasaki, 1987;Hashimoto et al., 2015). Those paleontological studies indicate that the depositional ages are younging toward the east. On the other hand, the paleocurrent directions in the main facies suggest the sediment derivation was mainly from east-northeast to west-southwest (Suyari, 1973;Miyata, 2004), as opposed to the younging direction of the depositional ages. These facts imply that the sedimentary basin of the Izumi Group had been developed in association with strike-slip fault activities (Ichikawa et al., 1981;Miyata, 1989;Noda and Toshimitsu, 2009). Progressive fault displacements along the pull-apart basins could migrate the basin depocenters (e.g., Noda, 2013).Recently, details of the Late Cretaceous volcanic activities in the Sanyo Belt, which is situated at the north of the Izumi Group, were revealed by using U-Pb ages of igneous zircon grains in the felsic volcanic rocks and welded tuff beds (Sato, 2016; Sato et al., 2016a, b) (Fig. 1A). Therefore, radioisotope geochronological data in the Izumi Group may be useful to compare with the volcanic activities in magmatic fronts and to discuss temporal and spatial evolution of the sedimentary basin during the Late Cretaceous time. Although there are a few fission-track ages reported from the Izumi Group of Shikoku Island and the Kii Peninsula (Fig. 1A), no FT and U-Pb age data have been reported from eastern Shikoku to date. This paper reports LA-ICP-MS U-Pb and FT ages of zircons in two felsic tuff beds of the Takikubo Formation (Yamasaki, 1986;Matsuura et al., 2002), which is the lower most formation of the main facies ...

show abstract

“…1 , 1965Fig. 1 Miura, 1999;, 2007;, 2007;Kawakami et al, 2007Kawakami et al, , 2004, 2007 100 km 1970, 1974, 1975;, 1978, 1988, 1982;, 1993;, 1997, , 1973, Blow, 1969, N.8 N.10 , 1978, 1982Okada and Bukry, 1980CN3 CN5a , 1982, 1997, , 1987, BF1 , 1970, , 1974, 1988 Kbi (2) and (3) the present study. Orbulina sp.…”

mentioning

confidence: 99%

新潟堆積盆七谷層中に見つかった中期中新世広域テフラ：Kbiテフラと紀伊半島室生火砕流堆積物の対比

Kudo¹,

Danhara²,

Iwano³

et al. 2011

Jour. Geol. Soc. Japan

View full text Add to dashboard Cite

The Komadegawa-biotite (Kbi) tephra is a crystal-rich coarse tuff layer ( cm thick) intercalated in the upper part of the Middle Miocene Nanatani Formation in the eastern area of the Niigata sedimentary basin, northeast Japan. The Kbi tephra contains plagioclase (oligoclase to labradorite in composition), quartz, sanidine, biotite, trace amounts of garnet, and reddish and colorless zircons. The Kbi tephra is intercalated in the N. planktonic foraminiferal zone and the CN calcareous nannofossil zone, corresponding to an age of . -. Ma, which is consistent with a newly determined fission track age of .. Ma ( σ). On the basis of the petrography, fission track age and biostratigraphy, the Kbi tephra is correlated to the Muro Pyroclastic Flow Deposit in Kii Peninsula and the Kn-tephra in Boso Peninsula. These tephras are considered as a widespread tephra layer associated with the formation of the Kumano Acidic Rocks in Kii Peninsula. This tephra is expected to be found across large parts of Japan and provides a stratigraphic marker in various sedimentary basins.

show abstract

Heterogeneous distribution of uranium within zircon grains: Implications for fission-track dating.

Cited by 19 publications

References 6 publications

The incorporation of hydroxyl groups and molecular water in natural zircon (ZrSiO4)

The incorporation of hydroxyl groups and molecular water in natural zircon (ZrSiO4)

LA-ICP-MS U–Pb and fission-track ages of felsic tuff beds of the Takikubo Formation, Izumi Group in the Kan-onji district, eastern Shikoku, southwestern Japan

新潟堆積盆七谷層中に見つかった中期中新世広域テフラ：Kbiテフラと紀伊半島室生火砕流堆積物の対比

Contact Info

Product

Resources

About