Stratigraphic record of continental breakup, offshore NW Australia—Discussion. (16th November 2022)

• Record Type: Journal Article
• Authors: Alves, Tiago M.; Fetter, Marcos; Busby, Cathy; Cunha, Tiago A.; Mattos, Nathalia H.
• Is Part Of: Basin research. Volume 35:Number 1(2023)
• Page Start: 470
• Page End: 482
• Publication Date: 2022-11-16
• Subjects: breakup -- breakup sequences -- Continental margins -- rifting -- stratigraphy; Sedimentation and deposition -- Periodicals; Sedimentary basins -- Periodicals; 551
• DOI: 10.1111/bre.12728
• Languages: English
• ISSNs: 0950-091X

Abstract

Abstract: Reeve et al. (2022) address the stratigraphic record of continental breakup by focusing on a set of stratigraphic unconformities from a proximal sector of the NW Australian continental margin, inboard from the Exmouth Plateau. They suggest that such unconformities can potentially document a well‐defined three‐stage process: end of the syn‐rift phase, formation of a wide continent‐ocean transition zone (COTZ) and generation of 'true' Penrose‐type oceanic crust. We counterargue that continental breakup is a protracted event that can only be understood via seismic‐ and chronostratigraphic correlations of strata, and their composing sequences, across and along rifted margins. Tying proximal stratigraphic unconformities to magnetic anomalies outboard from the study area in Reeve et al. (2022) is open to question. In parallel, we suggest that age resolutions of ca. 1 Ma are not achievable using the micropaleontological data presented in Reeve et al. (2022), with an important reworking of microfossil assemblages potentially occurring during the erosional process forming local and regional unconformities. Our discussion addresses these points in more detail. Abstract : Seismic profile from Northwest Iberia showing an older Breakup Sequence A, which relates to continental breakup in the Tagus Abyssal Plain, and Breakup Sequence B above, correlated with continental breakup in the Iberia Abyssal Plain.