Paleomagnetic constraints on the link between the Comei-Bunbury large igneous province and the Kerguelen mantle plume

Abstract

The causal link between the Comei-Bunbury large igneous province (CBLIP) and the Kerguelen mantle plume (KMP) remains a topic of debate. Here, a new paleomagnetic study was conducted on the Zhela Formation basalts and sandstones (ca. 147–140 Ma) in the Taga area of the eastern Tethyan Himalaya (TH). The sandstone specimens had erratic demagnetization patterns, and reliable characteristic remanent magnetization (ChRM) directions could not be isolated. Positive fold and reversal tests indicate that the ChRM directions of the Zhela Formation basalts should be the primary magnetization. The tilt-corrected site-mean direction from 18 sites is D/I = 87.8°/70.0° (α95 = 6.8°), yielded a paleopole of 21.6°N/130.2°E (A95 = 12.0°) and a paleolatitude of 54.7° ± 12.0°S for the study area (28.4°N, 91.8°E). Comparison with robust latest Jurassic and Early Cretaceous paleomagnetic, geochemical, and geochronological data from the eastern TH, northeastern Indian craton, and southwestern Australia reveal that (1) the eruption periods of the Comei igneous rocks are similar to the Bunbury basalt (and the Naturaliste Plateau volcanic rocks); (2) the original erupted positions of the Comei-Bunbury (CB) igneous rocks were in agreement with the reconstructed KMP; and (3) the CBLIP originated from the KMP.