干旱区生态环境知识资源中心(Arid): Combined zircon U-Pb dating and chemical Th-U-total Pb chronology of monazite and thorite, Abu Diab A-type granite, Central Eastern Desert of Egypt: Constraints on the timing and magmatic-hydrothermal evolution of rare metal granitic magmatism in the Arabian Nubian Shield

Arid

DOI	10.1016/j.chemer.2020.125669
	Combined zircon U-Pb dating and chemical Th-U-total Pb chronology of monazite and thorite, Abu Diab A-type granite, Central Eastern Desert of Egypt: Constraints on the timing and magmatic-hydrothermal evolution of rare metal granitic magmatism in the Arabian Nubian Shield
	Mahdy, Nasser M.; Ntaflos, Theodoros; Pease, Victoria; Sami, Mabrouk; Slobodnik, Marek; Abu Steet, Ahmed A.; Abdelfadil, Khaled M.; Fathy, Douaa
通讯作者	Mahdy, NM (corresponding author), Nucl Mat Author, PO 530, Cairo, Egypt.
来源期刊	GEOCHEMISTRY
ISSN	0009-2819
EISSN	1611-5864
出版年	2020
卷号	80 期号:4
英文摘要	We present the first chemical age determination of monazite from a geochemically-specialized rare metal granite of the Central Eastern Desert (CED), Egypt. The Abu Diab composite A-type granite of the CED divides into three co-magmatic phases: two mica granite (TG), garnet-bearing muscovite granite (GMG), and muscovite granite (MG). The GMG granitic phase is a typical example of a rare metal, volatile-rich aqueous silicate magma. Its zircon has extremely high U-concentration (up to 45,000 ppm) and intense metamictization, resulting in significant radiogenic Pb-loss, as well as common Pb contamination, along fractures and other imperfections. Laser ablation (LA-ICP-MS) zircon U-Pb results yield imprecise to meaningless dates. On the other hand, the GMG exhibits two texturally and chemically distinct varieties of monazite, pristine (Mnz1) and altered (Mnz2), that yield similar electron microprobe (EMP) chemical ages of 587 +/- 8 Ma (2 sigma) for Mnz1 and 587 +/- 9 Ma (2 sigma) for Mnz2. These ages, combined with the inferred alteration temperature (T > 400 degrees C), indicate monazite alteration/replacement occurred during or soon after crystallization of the pluton, in response to expelled magmatic-hydrothermal fluids inferred to be F-rich, late-staged deuteric fluids. The alteration and elemental substitution of zircon and monazite reflect coupled dissolution-recrystallization processes during late-staged deuteric alteration when zircon and thorite were relatively vulnerable to post-magmatic hydrothermal effects because of their extremely metamict state. The ca. 587 Ma age is typical of A-type granite intrusion across the CED and the post-collisional stage of the Arabian Nubian Shield (ANS; 610 - 560 Ma), and is within analytical error of associated magmatic thorite (592 +/- 8 Ma). These two ages agree with the timing of rare metal-rich intrusions (0.6-0.4 Ga) related to the Pan-African orogeny. Future research using the monazite chronometer may better constrain the timing of rare metal granitic magmatism of the ANS.
英文关键词	Monazite chronology Thorite Metamict zircon Rare metal bearing granite Arabian Nubian Shield Late-staged magmatic fluids
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000617623200013
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/348878
作者单位	[Mahdy, Nasser M.; Abu Steet, Ahmed A.] Nucl Mat Author, PO 530, Cairo, Egypt; [Ntaflos, Theodoros] Univ Vienna, Dept Lithospher Res, Althanstr 14, A-1090 Vienna, Austria; [Pease, Victoria] Stockholm Univ, Petro Tecton Facil, Dept Geol Sci, SE-10691 Stockholm, Sweden; [Sami, Mabrouk; Fathy, Douaa] Menia Univ, Geol Dept, Fac Sci, El Minia 61519, Egypt; [Slobodnik, Marek] Masaryk Univ, Inst Geol Sci, Kotkuslca 2, Brno 61137, Czech Republic; [Abdelfadil, Khaled M.] Sohag Univ, Fac Sci, Geol Dept, Sohag 82524, Egypt
推荐引用方式 GB/T 7714	Mahdy, Nasser M.,Ntaflos, Theodoros,Pease, Victoria,et al. Combined zircon U-Pb dating and chemical Th-U-total Pb chronology of monazite and thorite, Abu Diab A-type granite, Central Eastern Desert of Egypt: Constraints on the timing and magmatic-hydrothermal evolution of rare metal granitic magmatism in the Arabian Nubian Shield[J],2020,80(4).
APA	Mahdy, Nasser M..,Ntaflos, Theodoros.,Pease, Victoria.,Sami, Mabrouk.,Slobodnik, Marek.,...&Fathy, Douaa.(2020).Combined zircon U-Pb dating and chemical Th-U-total Pb chronology of monazite and thorite, Abu Diab A-type granite, Central Eastern Desert of Egypt: Constraints on the timing and magmatic-hydrothermal evolution of rare metal granitic magmatism in the Arabian Nubian Shield.GEOCHEMISTRY,80(4).
MLA	Mahdy, Nasser M.,et al."Combined zircon U-Pb dating and chemical Th-U-total Pb chronology of monazite and thorite, Abu Diab A-type granite, Central Eastern Desert of Egypt: Constraints on the timing and magmatic-hydrothermal evolution of rare metal granitic magmatism in the Arabian Nubian Shield".GEOCHEMISTRY 80.4(2020).