Constraints on the tectonic evolution of the Namaqua Province III: palaeomagnetic and 40 Ar/39Ar results from the Gannakouriep dyke swarm ( South Africa).

Tullis C. Onstott; R. B. Hargraves; D. L. Reid

Constraints on the tectonic evolution of the Namaqua Province III: palaeomagnetic and ⁴⁰ Ar/³⁹Ar results from the Gannakouriep dyke swarm ( South Africa).

Tullis C. Onstott
, R. B. Hargraves
, D. L. Reid

Research output: Contribution to journal › Article › peer-review

Abstract

Palaeomagnetic samples were collected from 2 dykes belonging to the Gannakouriep dyke swarm, one located in the centre of the Richtersveld subprovince (8215), the other further S in the Steinkopf Domain (8212), where it has been clearly overprinted by a later metamorphic episode. Detailed thermal and A.F. demagnetization indicate that the primary remanence has been extensively overprinted in both dykes. The ⁴⁰Ar/³⁹Ar step-heating analyses of a whole-rock sample of the 8212 yield a plateau spectrum with an integrated age of 542 + or - 4 Ma; whereas, the ⁴⁰Ar/³⁹Ar spectrum for a whole-rock sample of 8215 yields a saddle-shaped spectrum with the minimum at approx 400 Ma.-from Authors

Original language	English (US)
Pages (from-to)	171-183
Number of pages	13
Journal	Transactions - Geological Society of South Africa
Volume	89
Issue number	2
State	Published - 1986

All Science Journal Classification (ASJC) codes

General Environmental Science
General Engineering
General Earth and Planetary Sciences

Cite this

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title = "Constraints on the tectonic evolution of the Namaqua Province III: palaeomagnetic and 40 Ar/39Ar results from the Gannakouriep dyke swarm ( South Africa).",

abstract = "Palaeomagnetic samples were collected from 2 dykes belonging to the Gannakouriep dyke swarm, one located in the centre of the Richtersveld subprovince (8215), the other further S in the Steinkopf Domain (8212), where it has been clearly overprinted by a later metamorphic episode. Detailed thermal and A.F. demagnetization indicate that the primary remanence has been extensively overprinted in both dykes. The 40Ar/39Ar step-heating analyses of a whole-rock sample of the 8212 yield a plateau spectrum with an integrated age of 542 + or - 4 Ma; whereas, the 40Ar/39Ar spectrum for a whole-rock sample of 8215 yields a saddle-shaped spectrum with the minimum at approx 400 Ma.-from Authors",

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T1 - Constraints on the tectonic evolution of the Namaqua Province III

T2 - palaeomagnetic and 40 Ar/39Ar results from the Gannakouriep dyke swarm ( South Africa).

AU - Onstott, Tullis C.

AU - Hargraves, R. B.

AU - Reid, D. L.

PY - 1986

Y1 - 1986

N2 - Palaeomagnetic samples were collected from 2 dykes belonging to the Gannakouriep dyke swarm, one located in the centre of the Richtersveld subprovince (8215), the other further S in the Steinkopf Domain (8212), where it has been clearly overprinted by a later metamorphic episode. Detailed thermal and A.F. demagnetization indicate that the primary remanence has been extensively overprinted in both dykes. The 40Ar/39Ar step-heating analyses of a whole-rock sample of the 8212 yield a plateau spectrum with an integrated age of 542 + or - 4 Ma; whereas, the 40Ar/39Ar spectrum for a whole-rock sample of 8215 yields a saddle-shaped spectrum with the minimum at approx 400 Ma.-from Authors

AB - Palaeomagnetic samples were collected from 2 dykes belonging to the Gannakouriep dyke swarm, one located in the centre of the Richtersveld subprovince (8215), the other further S in the Steinkopf Domain (8212), where it has been clearly overprinted by a later metamorphic episode. Detailed thermal and A.F. demagnetization indicate that the primary remanence has been extensively overprinted in both dykes. The 40Ar/39Ar step-heating analyses of a whole-rock sample of the 8212 yield a plateau spectrum with an integrated age of 542 + or - 4 Ma; whereas, the 40Ar/39Ar spectrum for a whole-rock sample of 8215 yields a saddle-shaped spectrum with the minimum at approx 400 Ma.-from Authors

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Constraints on the tectonic evolution of the Namaqua Province III: palaeomagnetic and ⁴⁰ Ar/³⁹Ar results from the Gannakouriep dyke swarm ( South Africa).

Abstract

All Science Journal Classification (ASJC) codes

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