Formation mechanism of the global Dupal isotope anomaly

Abstract

The Dupal anomaly has been a frequently discussed feature since it was first proposed three decades ago. We here limit the distribution of the Dupal anomaly based on more than 10 000 Sr–Nd–Pb isotopic composition analyses and classify the anomaly into three types, located in three different oceans and with different mechanisms of formation. The Dupal anomaly in the East Asian Continental Margin subduction zone is related to enriched mantle II, which may originate from the recycling of the subducting plate or continental mantle. The high μ and enriched mantle I are the reason for the Dupal anomaly in the Pacific Ocean, which is related to the superplume. However, the source of the Dupal anomaly in the Indian Ocean and the Southern Atlantic Ocean is a mixture of enriched mantle I and enriched mantle II, and they come from the African superplume and the recycling of subcontinental mantle or continental crust of Gondwana. In consideration of all the above factors, we suggest that the superplume from the core–mantle boundary, the recycling subducting plate and continental mantle are the main characteristics of the global Dupal anomaly. Copyright © 2016 John Wiley & Sons, Ltd.

High‐potassium volcanic rocks from the Okinawa Trough: Implications for a cryptic potassium‐rich and DUPAL‐like source

“…DUPAL‐like signatures have been widely discovered within the mantle sources of East and Southeast Asia (e.g., Flower et al, ; Hoang, Flower, & Carlson, ; Tatsumoto & Nakamura, ) and Western Pacific basins (e.g., Hickey‐Vargas, ; Hoang & Uto, ; Pearce & Stern, ). To date, the origins of the isotopic anomalies in these areas remain uncertain (Zhang, Li, Suo, Somerville, & Li, ). Some researchers have ascribed this Pb isotopic enrichment to the extrusion of Indian Ocean MORB mantle beneath the Western Pacific and its adjacent region (e.g., Castillo, ; Hickey‐Vargas, ; Hickey‐Vargas, Hergt, & Spadea, ; Mukasa, McCabe, & Gill, ) or to the influx of mantle plumes with the same isotopic characteristics as Indian Ocean MORB (e.g., Turner & Hawkesworth, ; Volpe, Douglas Macdougall, & Hawkins, ).…”

Preface: Earth system evolution of the Pacific and Indian oceans and the South China Sea

“…Z. Zhang et al . () limit the distribution of the Dupal anomaly based on more than 10 000 Sr–Nd–Pb isotopic composition analyses of oceanic basalts and classify the Dupal anomaly from four different oceanic regions into three types with different formation mechanisms.…”