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Paleomagnetic evidence for the paleoposition of Sumba island, Indonesia

1981; Elsevier BV; Volume: 52; Issue: 1 Linguagem: Inglês

10.1016/0012-821x(81)90211-9

1385-013X

Yo‐ichiro Otofuji, Sadao Sasajima, Susumu Nishimura, Takuo Yokoyama, Sapri Hadiwisastra, Fred Hehuwat,

Geology and Paleoclimatology Research

Abstract Jurassic paleomagnetic directions have been obtained for the sedimentary rocks in Sumba. The mean direction is 59.2° in declination and −44.2° in inclination. The reliability of the direction is ascertained through thermal demagnetization and the presence of normal and reversed polarities. Comparison with the Permian paleomagnetic direction of Timor indicates that Sumba was subjected to a clockwise rotation through 79.4° relative to Timor since the Jurassic. When Sumba is restored by a counter-clockwise rotation, the Sumba pole is gradually approaching the Jurassic pole of Australia as well as the Timor Permian pole. This implies that, at least until the Jurassic, Sumba and Timor were situated at the Australian continental margin and that Sumba rotated clockwise during or after the Jurassic.