TY  - JOUR
T1  - Strain Partitioning and Dimensional Preferred Orientation in a syn-Tectonic Granitoid, S.E. Nigeria
AU - Oden, Michael I. 
JO  - Research Journal of Applied Sciences
VL  - 7
IS  - 3
SP  - 158
EP  - 164
PY  - 2012
DA  - 2001/08/19
SN  - 1815-932x
DO  - rjasci.2012.158.164
UR  - https://makhillpublications.co/view-article.php?doi=rjasci.2012.158.164
KW  - phenocrysts
KW  -orientation
KW  -arithmetic
KW  -geometric
KW  -harmonic
KW  -Strain
AB  - Uwet granodiorite, a syn-tectonic granitoid of Pan-African 
  age in South Eastern Nigeria is partly porphyritic, containing megacrysts of 
  K-feldspars, xenoliths and ellipsoidal bodies. The preferred orientations of 
  the feldspar phenocrysts are in the NE-SW, NW-SE and N-S, the strongest being 
  the NW-SE trend. The E-W sectors show minimum grain orientation. Calculated 
  values of strain-arithmetic mean <img src="http://docsdrive.com/images/medwelljournals/rjasci/2012/img1-2k12-158-164.gif" width="13" height="13" align="absmiddle"> 
  , geometric mean G and harmonic mean H show minimum strain for grains in E-W 
  orientation and maximum strain for grains in N-S orientation. Phenocrysts in 
  NE-SW and NW-SE orientations showed intermediate values of strain with the latter 
  axis having higher values than the former. Generally, irrespective of orientation 
  or axis, the relationship <img src="http://docsdrive.com/images/medwelljournals/rjasci/2012/img1-2k12-158-164.gif" width="13" height="13" align="absmiddle">&gt; 
  G&gt;H was found to hold. The analysis favours the interpretation that when 
  two simple shears and a pure shear operate simultaneously in a viscous/ductile 
  matrix at high temperature under a non-hydrostatic stress state, dimensional 
  preferred orientation and strain are partitioned unequally along those axes. 
  The paucity of phenocryst orientation and low strain values in the E-W axis 
  are an indication that maximum compressive stress (<img src="http://docsdrive.com/images/medwelljournals/rjasci/2012/img2-2k12-158-164.gif" width="13" height="15" align="absmiddle">) 
  was oriented in this direction, during the Orogeny.
ER  -