Detrital zircon provenance of Permo-Carboniferous glacial diamictites across Gondwana
| Autor: | Arthur J. Mory, David H. Malone, G.A. Botha, Joe R Martin, John P. Craddock, Paulo Roberto dos Santos, George E. Gehrels, Richard W. Ojakangas, Matthew S.A. Horstwood, Jonathan Redfern, Anthony Rochas-Campos, Kathryn N. Pauls, Alexandros Konstantinou, Wilfried Bauer, Suzanne Craddock Affinati, Udo Zimmerman, Eric Tohver, Robert J. Thomas, Claudio Riccomini |
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| Rok vydání: | 2019 |
| Předmět: |
geography
geography.geographical_feature_category ZIRCÃO 010504 meteorology & atmospheric sciences Paleozoic Ice stream Ice field 010502 geochemistry & geophysics 01 natural sciences Supercontinent Paleontology Gondwana 13. Climate action General Earth and Planetary Sciences Snowball Earth Ice sheet Geology 0105 earth and related environmental sciences Terrane |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| ISSN: | 0012-8252 |
| DOI: | 10.1016/j.earscirev.2019.01.014 |
| Popis: | Gondwana changed its high latitude location during the late Paleozoic (338–265 Ma), relative to the South Pole, and the style of glaciation evolved from localized alpine glaciers and ice fields to ~30 small ice sheets across the supercontinent. We report the analysis of heavy mineral populations (n = 2217) and the ages of detrital zircons (n = 2920 U-Pb LA-ICPMS results) from Gondwana diamictite deposits from eight landmasses: Africa (5 samples), Antarctica (5), Australia (8), the Ellsworth Mountains terrane (1, Antarctica), the Falkland Islands (2, diamictite plus U-Pb SHRIMP ages on granite clasts), India (1), Madagascar (1), Oman (3), the equatorial Lhasa terrane (2), the equatorial North Qiantang terrane (2) and South America (10). Heavy mineral separations (SEM-WDS analysis) identified one anomaly, pyrope garnets present only in Dwyka Group and Dwyka-equivalent samples suggesting an ultramafic Antarctic source. Statistical analysis of detrital zircon age distributions support the inference of local transport of sediment from many small ice centers with five examples of far-field ice transport (>1000 km; four with ice flow >2000 km), and three from ice fields located along coastal Antarctica. We propose that ice was distributed from five main ice-caps of different ages in southern Gondwana with ice flow away from central Gondwana. We also confirm that the Permo-Carboniferous detrital zircon populations of Euramerica (eolian and fluvial) and Gondwana (ash, detrital-glacial) are not mixed across the equator or seaway and ponder the possibility of a late Paleozoic snowball Earth. |
| Databáze: | OpenAIRE |
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