A succession of 5 FIA trends（foliation intersection or inflection axes in porphyroblasts） preserved in high temperature-low pressure regime PreCambrian rocks in the Texas Creek, Arkansas River region reflected by th...A succession of 5 FIA trends（foliation intersection or inflection axes in porphyroblasts） preserved in high temperature-low pressure regime PreCambrian rocks in the Texas Creek, Arkansas River region reflected by the fold axial plane traces and schistosity data in this region. Similar fold axial plane trace data measured in Palaeozoic rocks in Chester Dome, Vermont, which is high temperature to medium pressure regime, only preserve the effects of the youngest FIAs of the all 5 FIA sets that obtained in this region. The other three FIA sets have no equivalent fold axial planes. This difference from shallow to deeper orogenic regimes reflects decreasing competency at greater pressure with collapse and unfolding of earlier formed folds. The greater overlying load of rocks has tended to flatten all but the very largest early-formed structures, preserving only those folds that were more recently developed.展开更多
With the realization that rocks with a schistosity parallel to bedding(S0 parallel S1)have undergone lengthy histories of deformation that predate the obvious first deformation(e.g.Bell et al.,2003; Sayab,2006;Yeh,200...With the realization that rocks with a schistosity parallel to bedding(S0 parallel S1)have undergone lengthy histories of deformation that predate the obvious first deformation(e.g.Bell et al.,2003; Sayab,2006;Yeh,2007)came recognition that large scale regional folds can form early during this process and be preserved throughout orogenesis(e.g.,Ham & Bell,2004;Bell & Newman,2006).This history is lost within the matrix because of reactivational shear展开更多
基金supported in part by grants from National Natural Science Foundation of China (41202153)China Council Scholarship (2013693)+1 种基金MLR, China (201211093)Institute of Geology, CAGS (J1101)
文摘A succession of 5 FIA trends（foliation intersection or inflection axes in porphyroblasts） preserved in high temperature-low pressure regime PreCambrian rocks in the Texas Creek, Arkansas River region reflected by the fold axial plane traces and schistosity data in this region. Similar fold axial plane trace data measured in Palaeozoic rocks in Chester Dome, Vermont, which is high temperature to medium pressure regime, only preserve the effects of the youngest FIAs of the all 5 FIA sets that obtained in this region. The other three FIA sets have no equivalent fold axial planes. This difference from shallow to deeper orogenic regimes reflects decreasing competency at greater pressure with collapse and unfolding of earlier formed folds. The greater overlying load of rocks has tended to flatten all but the very largest early-formed structures, preserving only those folds that were more recently developed.
文摘With the realization that rocks with a schistosity parallel to bedding(S0 parallel S1)have undergone lengthy histories of deformation that predate the obvious first deformation(e.g.Bell et al.,2003; Sayab,2006;Yeh,2007)came recognition that large scale regional folds can form early during this process and be preserved throughout orogenesis(e.g.,Ham & Bell,2004;Bell & Newman,2006).This history is lost within the matrix because of reactivational shear
