Development of a new paleopiezometer based on deformation microstructures : application to mantle flow

结构和面料的分析，以及暴露的希尔蒂地幔部分，阿曼蛇绿岩，表明剪切带的发展，这可能是由于海洋板块的破碎，是受预先存在的地幔结构存在于古脊。地幔部分的详细结构测绘显示出一个东西向流动的平缓起伏结构。一条北西-南东向的走滑剪切带横穿该水平构造。叶理中橄榄石的晶体择优取向（CPO）主要由（010）轴向模式而不是更常见的（010）[100]模式控制，这表明莫霍面附近的水平流动涉及非同轴流动。低温剪切带中的橄榄石CPO具有（001）[100]型和左旋剪切方向的特征。大洋地幔岩石圈在俯冲和仰冲过程中的结构行为可能受到大洋扩张中心形成的初始力学各向异性的强烈影响。

Structural and fabric analysis of the well-exposed Hilti mantle section, Oman ophiolite, suggests that shear zone development, which may have resulted from oceanic plate fragmentation, was influenced by pre-existing mantle fabric present at the paleo-ridge. Detailed structural mapping in the mantle section revealed a gently undulating structure with an east-west flow direction. A NW-SE strike-slip shear zone cuts across this horizontal structure. The crystal preferred orientation (CPO) of olivine within the foliation is dominated by (010) axial patterns rather than more commonly observed (010) [100] patterns, suggesting that the horizontal flow close to the Moho involved non-coaxial flow. Olivine CPO within the shear zone formed at low temperature is characterized by (001) [100] patterns and a sinistral sense of shear. The structural behavior of oceanic mantle lithosphere during subduction and obduction may be strongly influenced by initial mechanical anisotropy developed at an oceanic spreading center.