Age and generation of Fogang granite batholith and Wushi diorite-hornblende gabbro body

Xi Sheng Xu*, Wei Min Lu, Zhen Yu He

*Corresponding author for this work

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Fogang granitic batholith, the largest Late Mesozoic batholith in the Nanling region, has an exposure area of ca. 6000 km2. Wushi diorite-homblende gabbro body is situated at the northeast part of the batholith. Both the granitic batholith main body and the diorite-homblende gabbro body belong to high-K calc alkaline series. Compared with the granitic main body, the Wushi body has lower Si (49%-55%), higher Fe, Mg, Ca, lower REE, less depletion of Eu, Ba, P, Ti, and obvious depletion of Zr, Hf. Zircon LA-ICP-MS dating and the mineral-whole rock isochron dating reveal that Fogang granitic main body and Wushi body were generated simultaneously at ca. 160 Ma. The Fogang granitic main body has high (87Sr/86Sr)i ratios (0.70871-0.71570) and low εNd(t) values (-5.11-8.93), suggesting the origins of the granitic rocks from crustal materials. Their Nd two-stage model ages range from 1.37-1.68 Ga. The Sr and Nd isotopic compositions and the Nd model ages of the granitic rocks may suggest that the giant Fogang granitic main body was generated from a heterogeneous source, with participation of mantle component. Wushi diorite-homblende gabbro is an unusual intermediate-basic magmatic rock series, with high (87Sr/86Sr)i ratios (0.71256-0.71318) and low εNd(t) values (-7.32-7.92), which was possibly formed through mixing between the mantle-derived juvenile basaltic magma and the magma produced by the dehydration melting of lower crustal basaltic rocks.

Original languageEnglish
Pages (from-to)209-220
Number of pages12
JournalScience in China, Series D: Earth Sciences
Volume50
Issue number2
DOIs
Publication statusPublished - Feb 2007
Externally publishedYes

Keywords

  • Granite
  • Higher initial Sr/Sr diorite
  • Isotopic dating
  • Nanling
  • Source component

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