Origin and tectonic evolution of the NE basement of Oman

a window into the Neoproterozoic accretionary growth of India?

BRANDON L. ALESSIO, MORGAN L. BLADES, GEORGE MURRAY, BENJAMIN THORPE, ALAN S. COLLINS, DAVID E. KELSEY, JOHN FODEN, JUSTIN PAYNE, SALAH AL-KHIRBASH, FRED JOURDAN

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The Omani basement is located spatially distant from the dominantly juvenile Arabian–Nubian Shield (ANS) to its west, and its relationship to the amalgamation of those arc terranes has yet to be properly constrained. The Jebel Ja'alan (NE Oman) basement inlier provides an excellent opportunity to better understand the Neoproterozoic tectonic geography of Oman and its relationship to the ANS. To understand the origin of this basement inlier, we present new radiogenic isotopic data from igneous bodies in Jebel Ja'alan. U–Pb and 40Ar/39Ar geochronological data are used to constrain the timing of magmatism and metamorphism in the jebel. Positive εHf and εNd values indicate a juvenile origin for the igneous lithologies. Phase equilibria modelling is used to constrain the metamorphic conditions recorded by basement. Pressure–temperature (P–T) pseudosections show that basement schists followed a clockwise P–T path, reaching peak metamorphic conditions of c. 650–700°C at 4–7.5 kbar, corresponding to a thermal gradient of c. 90–160°C/kbar. From the calculated thermal gradient, in conjunction with collected trace-element data, we interpret that the Jebel Ja'alan basement formed in an arc environment. Geochronological data indicate that this juvenile arc formed during Tonian time and is older than basement further west in Oman. We argue that the difference in timing is related to westwards arc accretion and migration, which implies that the Omani basement represents its own tectonic domain separate to the ANS and may be the leading edge of the Neoproterozoic accretionary margin of India.

Original languageEnglish
Pages (from-to)1-25
Number of pages25
JournalGeological Magazine
DOIs
Publication statusAccepted/In press - Mar 7 2017

Fingerprint

tectonic evolution
shield
inlier
tectonics
phase equilibrium
schist
magmatism
terrane
lithology
metamorphism
accretion
trace element
modeling

Keywords

  • Jebel Ja'alan
  • palaeogeography
  • pseudosection
  • thermochronology
  • U–Pb geochronology

ASJC Scopus subject areas

  • Geology

Cite this

ALESSIO, BRANDON. L., BLADES, MORGAN. L., MURRAY, GEORGE., THORPE, BENJAMIN., COLLINS, ALAN. S., KELSEY, DAVID. E., ... JOURDAN, FRED. (Accepted/In press). Origin and tectonic evolution of the NE basement of Oman: a window into the Neoproterozoic accretionary growth of India? Geological Magazine, 1-25. https://doi.org/10.1017/S0016756817000061

Origin and tectonic evolution of the NE basement of Oman : a window into the Neoproterozoic accretionary growth of India? / ALESSIO, BRANDON L.; BLADES, MORGAN L.; MURRAY, GEORGE; THORPE, BENJAMIN; COLLINS, ALAN S.; KELSEY, DAVID E.; FODEN, JOHN; PAYNE, JUSTIN; AL-KHIRBASH, SALAH; JOURDAN, FRED.

In: Geological Magazine, 07.03.2017, p. 1-25.

Research output: Contribution to journalArticle

ALESSIO, BRANDONL, BLADES, MORGANL, MURRAY, GEORGE, THORPE, BENJAMIN, COLLINS, ALANS, KELSEY, DAVIDE, FODEN, JOHN, PAYNE, JUSTIN, AL-KHIRBASH, SALAH & JOURDAN, FRED 2017, 'Origin and tectonic evolution of the NE basement of Oman: a window into the Neoproterozoic accretionary growth of India?', Geological Magazine, pp. 1-25. https://doi.org/10.1017/S0016756817000061
ALESSIO BRANDONL, BLADES MORGANL, MURRAY GEORGE, THORPE BENJAMIN, COLLINS ALANS, KELSEY DAVIDE et al. Origin and tectonic evolution of the NE basement of Oman: a window into the Neoproterozoic accretionary growth of India? Geological Magazine. 2017 Mar 7;1-25. https://doi.org/10.1017/S0016756817000061
ALESSIO, BRANDON L. ; BLADES, MORGAN L. ; MURRAY, GEORGE ; THORPE, BENJAMIN ; COLLINS, ALAN S. ; KELSEY, DAVID E. ; FODEN, JOHN ; PAYNE, JUSTIN ; AL-KHIRBASH, SALAH ; JOURDAN, FRED. / Origin and tectonic evolution of the NE basement of Oman : a window into the Neoproterozoic accretionary growth of India?. In: Geological Magazine. 2017 ; pp. 1-25.
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AU - KELSEY, DAVID E.

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