Taylor, Lawrence A.; Snyder, Gregory A.; Keller, Randall; Remley, David A.; Anand, Mahesh; Wiesli, Rene; Valley, John and Sobolev, Nikolai V.
|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1007/s00410-003-0465-y|
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Mantle xenoliths from the Obnazhennaya kimberlite pipe, Yakutia, possess a large range of mineralogical and chemical compositions, from both group A and B eclogites. Major-element contents of the group A eclogites exhibit transitional features between the group B eclogites and peridotite. The Mg# of clinopyroxenes is 0.86–0.94, with 0.60–0.84 for garnets. Differences in concentration of LREEs exist between the Obnazhennaya group A and the well-studied group B eclogites from the Udachnaya kimberlite pipe. In general, garnets in the group A eclogites contain lower LREEs than those from the group B eclogites; however, the trend for clinopyroxene is reversed. High d 18O (5.46–7.81) values, and the positive Eu anomalies in the garnets and clinopyroxenes (Eu/Eu* 1.2–1.4) demonstrate the involvement of an oceanic crustal component in the formation of the group A eclogites. The group A eclogites formed between 21.0 and 37.6 kbar, and 711 and 923 °C, in a time interval of 1,071–1,237 Ma. An innovative model is proposed to explain the formation of the group A eclogites and websterites. It involves the reaction of a depleted mantle peridotite with TTG and carbonatite melts closely related to the subduction of oceanic crust.
|Item Type:||Journal Article|
|Extra Information:||Some of the symbols may not have transferred correctly into this bibliographic record.|
|Keywords:||kimberlite; Obnazhenaya; xenolith|
|Academic Unit/Department:||Science > Physical Sciences
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||Mahesh Anand|
|Date Deposited:||07 Jun 2006|
|Last Modified:||14 Jan 2016 15:47|
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