Comment on: "Does the Manning Orocline exist? New structural evidence from the inner hinge of the Manning Orocline (eastern Australia)" by Li and Rosenbaum (2013). Gondwana Research

The Manning Orocline is an enigmatic structure that has been the subject of much speculation with those advocating its existence (Korsch and Harrington, 1987; Glen and Roberts, 2012; Rosenbaum et al., 2012) to those sceptical of its existence (Lennox et al., 2013). In their recent contribution, Li and Rosenbaum (in press) provide evidence for this structure by analysing the geometry of the structural fabrics in the Armidale–Walcha area, an area that they suggest, comprises a less deformed part of the subduction–accretion complex of the southern New England Orogen. In their study area, the rocks show what appears to be a slaty cleavage (S1), that the authors suggest, delineates an oroclinal structure formed in the Permian. However, as shown in the following discussion, their S1 fabric can be either S1 or S2, and therefore, cannot be correlated across outcrops as a single surface. Thus, the structural history is far more complex than implied by Li and Rosenbaum (in press) and that the trends of the fabric they interpreted as S1 in the innermost hinge of the “Manning Orocline” are a mixture of fabrics formed during separate deformation and metamorphic events. We will present evidence in the following sections that show that preoroclinal structures have not been obliterated and that the area of interest has inherited a complex structural-metamorphic history related to the Carboniferous subduction–accretion history of the rocks. In addition, we will show that careful petrographic and field studies are essential to confirm the type and timing of cleavage formation before any model can be proposed. Finally, we will comment on some statements