Age and palaeoenvironmental constraints on the genesis of the Yandi channel iron deposits, Marillana Formation, Pilbara, northwestern Australia*

Autor: M S Stone, Michael Macphail
Rok vydání: 2004
Předmět:
Zdroj: Australian Journal of Earth Sciences. 51:497-520
ISSN: 1440-0952
0812-0099
DOI: 10.1111/j.1400-0952.2004.01071.x
Popis: Fossil pollen and spores preserved in organic‐rich claystones near the base of the palaeochannel hosting the Tertiary Yandi channel iron deposits (CID) provide an in situ constraint on the age of this world‐class orebody. This assemblage also aids understanding of the palaeoenvironment leading to the deposition and preservation of the host Marillana Formation. The provisional Early Oligocene age of claystones links the genesis of the Yandi CID to the profound disruption of global climates and oceanography at the Eocene‐Oligocene transition (Terminal Eocene Event) and provides circumstantial evidence that ore formation was linked to the development of a warm south‐flowing proto‐Leeuwin Current along the Pilbara coast. It is likely that rainfall increased but remained strongly seasonal (monsoonal?) as global climates warmed during the Late Oligocene — Early Miocene. The same fossil evidence indicates that wood fragments, the iron‐oxide‐replaced remains of which are a significant component of cemented goethi...
Databáze: OpenAIRE
Externí odkaz: