Feedback between topography and lithosphere–asthenosphere dynamics beneath the Yerer-Tulu Wellel volcano-tectonic lineament: Insights from apatite thermochronology and basalt geochemistry

Shelby Bowden, Nahid D. Gani, Tanya Furman, M. Royhan Gani, Matthijs VanSoest, Tsegaye Abebe, Tadesse Alemu, Paul O'Sullivan, Kibre Tadesse, Bekele Abebe

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Ethiopian topography is dominated by an ~2-km high plateau that underwent uplift and incision after or during the Cenozoic Flood Basalt event in the Early Oligocene; however, the timing and drivers of plateau dynamics are poorly constrained. We constrain the onset and causal mechanism of plateau uplift using thermochronologic and basaltic geochemical techniques. We performed low-temperature apatite fission track and (U–Th)/He thermochronologic dating on three Neoproterozoic basement rocks from the Yerer-Tullu Wellel volcano-tectonic lineament, directly west of Addis Ababa. Thermal models based on these results suggest this part of the plateau underwent slight heating in the Oligocene through Late Miocene, followed by rapid and recent cooling until the present day. To determine the nature of these Cenozoic thermal events, we compiled and reinterpreted a suite of partially published basaltic geochemical data. These geochemical data suggest this part of the plateau is underlain by a metasomatized and pyroxenite-rich lower lithosphere that began to drip into the asthenosphere in the Miocene. Fault-facilitated release of the lithospheric drip in the Late Cenozoic encouraged basin inversion, driving rapid cooling and incision within the last 5 Ma. Our study suggests that a direct coupling between lithospheric removal and topographic response highlights significant plateau formation around the Yerer-Tullu Wellel volcano-tectonic lineament zone within the Pliocene.

Original languageEnglish (US)
Pages (from-to)3569-3586
Number of pages18
JournalGeological Journal
Volume57
Issue number9
DOIs
StatePublished - Sep 2022
Externally publishedYes

Keywords

  • (U-Th)/He
  • Apatite fission track
  • Yerer-Tullu Wellel volcano-tectonic lineament
  • incision
  • lithospheric drip
  • low-temperature thermochronology

ASJC Scopus subject areas

  • Geology

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