LA-ICP-MS U–Pb zircon and FE-EPMA U–Th–Pb monazite dating of pelitic granulites from the Mt. Ukidake area, Sefuri Mountains, northern Kyushu

Journal of Mineralogical and Petrological Sciences

et al. 2016

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The Sør Rondane Mountains in East Antarctica consist of the various metamorphic rocks and several plutonic rocks, which are related to formation of Gondwana supercontinent. In order to understand the detrital provenances, LA-ICP-MS zircon U-Pb dating were conducted from metamorphosed sedimentary rocks in southern Sør Rondane Mountains. Detrital cores with~990-730 Ma ages were recognized from zircons in the pelitic gneisses and calc-silicate rocks from Menipa, Imingfjella, Mefjell and Arden, while the pelitic gneiss from Tvihøgda exhibited the Archean to Mesoproterozoic ages of~2630-1060 Ma. The Neoproterozoic zircon ages are recognized not only from metamorphosed sedimentary rocks but also from metamorphosed igneous rocks distributed in the central and southern parts of the mountains. However, the Archean to Mesoproterozoic zircon ages are rare in these areas. The results imply the detrital zircons with the Neoproterozoic ages were probably derived from neighbouring igneous rocks (present metamorphosed igneous rocks), while those with Archean to Mesoproterozoic ages have clearly different provenances because of the lack in the Neoproterozoic components. This study suggests the possibility that southern Sør Rondane Mountains can be considered to be juvenile late Mesoproterozoic to Neoproterozoic terrane partly mixed with the Archean to Mesoproterozoic components.

Section: La-icp-ms Zircon U-pb Dating Analytical Methodsmentioning

confidence: 99%

Detrital zircon provenances for metamorphic rocks from southern Sør Rondane Mountains, East Antarctica: A new report of Archean to Mesoproterozoic zircons

Kitano

Journal of Mineralogical and Petrological Sciences

et al. 2016

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“…EPMA U -Th -Pb Mnz dating was performed using the same JEOL JXA -8530F hyperprobe as described above, and the analytical procedures employed in this study closely followed those outlined in Adachi et al (2012). Determination of the chemical composition of Mnz in this study was carried out using thin sections of specimens, with an accelerating voltage of 15 kV, a probe current of 50 nA, and a 1 µm beam diameter.…”

Section: Epma U-th-pb Monazite Datingmentioning

confidence: 99%

EPMA U-Th-Pb monazite dating of metamorphic rocks from the Mogok Metamorphic Belt, central Myanmar

Yonemura

Journal of Mineralogical and Petrological Sciences

et al. 2013

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The Mogok Metamorphic Belt (MMB), situated in central Myanmar, contains an assemblage of high -grade metamorphic rocks believed to have been formed during a regional Early Eocene -Oligocene metamorphic event. We newly found Grt -Opx granulite in the Mogok area, which was formed under pressure -temperature (P -T ) conditions estimated as being 6.5 -8.7 kbar and 800 -950 °C. Based on the results of EPMA U -Th -Pb Mnz dating, the central MMB, which runs through the Mogok, Mandalay, and Meikthila areas, is characterized by an Eocene to Oligocene deformation and fluid infiltration event. In addition, several Mnz grains from the Meikthila and Mandalay areas record ages of the Late Triassic (~ 200 Ma) and Cretaceous (~ 80 Ma and 110 Ma) geologic events.

“…U -Pb zircon dating was performed using an Agilent 7500cx quadrupole inductively coupled plasma -mass spectrometer (ICP -MS) with a New Wave Research UP -213 Nd -YAG UV (213 nm) laser ablation system (LA), housed at Kyushu University, Japan. The analytical procedure is detailed by Adachi et al (2012). Sizes of analytical spots ranged between 25 μm and 55 μm.…”

Section: Methodsmentioning

confidence: 99%

U-Pb detrital zircon dating of pelitic schists and quartzite from the Kurosegawa Tectonic Zone, Southwest Japan

Yoshimoto

Journal of Mineralogical and Petrological Sciences

et al. 2013

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The Kurosegawa Tectonic Zone, which is one of the least geochronologically understood areas of the Japanese Islands, contains several rock types of contrasting ages in a serpentinite mélange. This paper presents the U -Pb ages of detrital zircons in pelitic schists and quartzite from the Kurosegawa Tectonic Zone, where high -pressure/low -temperature metamorphic rock (e.g., blueschist) is one of the main constituents. We analyzed a variety of samples including glaucophane -bearing pelitic schist from the Itsuki area in Kyushu and the Toba area on the Kii Peninsula, and quartzite from the Anan area in eastern Shikoku. The U -Pb age distributions reflect similar characteristics for all three areas, indicating significant peaks at 450 -500 Ma and ~ 600 Ma, with additional scattered ages of 800 -1800 Ma, and ages older than 2000 Ma. These results suggest that the provenance of the protolith of these high -pressure/low -temperature metamorphic rocks from the Kurosegawa Tectonic Zone would be the same between Kyushu and the Kii Peninsula through the Shikoku area. The distributions of detrital zircon ages in the Kurosegawa Tectonic Zone are similar to those from Permian -Triassic collision -related metamorphic rocks of the Ogcheon Metamorphic Belt and Gyeonggi Massif in South Korea, and from Devonian sedimentary rocks in the South China Craton.