Magma Evolution During Main-Phase Continental Flood Basalt Volcanism: A Case for Recharge-Evacuation-Assimilation-Fractional Crystallization in the Ethiopian Low-Ti Province

Creator(s):
Krans, Susan R; ORCID: 0000-0002-3936-0850
Rooney, Tyrone O
Kappelman, John W
Yirgu, Gezahegn
Ayalew, Dereje
Abstract:
Lavas erupted in Continental Flood Basalt (CFB) provinces are not primary magmas; they are differentiated products that result from large volumes of melt migrating and stalling in the lithosphere prior to eruption, resulting in complex liquid lines of descent. Geochemical models can be used to constrain the various influencers of magma differentiation (recharge, assimilation, fractional crystallization, eruption, and mixing). Temporal constraints for changes in plumbing system dynamics are recorded in the petrography and stratigraphy of the erupted lava flows. This study focuses on the flow-stratigraphy preserved within the Oligocene Ethiopian low-Ti flood basalt province, located on the NW Ethiopian Plateau. We present new bulk rock geochemistry from 107 lavas and interpret these data within a petrostratigraphic framework. Our model results suggest that both a deep (~0.6 GPa) and shallow (<0.2 GPa) magmatic system are active throughout the main phase of volcanism. Our recharge evacuation assimilation and fractional crystallization models (REAFC) show that during the main phase of magmatism evacuation from both the deep (65%) and shallow (55 %) systems reached an apex. During the terminal phases, magma evacuation from the deeper system ceases while evacuation from the shallow system is much reduced (25 %). The degree of crustal contamination predicted by REAFC (4 – 10 %) is lower than previous estimates determined for this region using assimilation with fractional crystallization only models (12-25%). Our study highlights the importance of evaluating petrography while interpreting geochemical models in Continental Flood Basalt.
How to cite this dataset:
Krans, S. R., Rooney, T. O., Kappelman, J. W., Yirgu, G., Ayalew, D., 2023. Magma Evolution During Main-Phase Continental Flood Basalt Volcanism: A Case for Recharge-Evacuation-Assimilation-Fractional Crystallization in the Ethiopian Low-Ti Province, Version 1.0. Interdisciplinary Earth Data Alliance (IEDA). https://doi.org/10.26022/IEDA/113048. Accessed 2024-05-25.
DOI Creation Date:
2023-10-10
License:
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International [CC-BY-NC-SA-4.0]
Funding source(s):
National Science Foundation: 1219647
National Science Foundation: 1219459
National Science Foundation: 0921009
Keyword(s):
Coverage Scope: Regional (Continents, Oceans)
Geographic Location: East Africa, NW Ethiopian plateau
User Contributed Keyword(s):
continental flood basalt, low-Ti
Data Available On:
2023-10-11
Resource Type:
Dataset
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3048-1_BulkSample_Analyses_Template_3_1.xlsx
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