Monday, October 24, 2016

Highlights—Imaging Cement Zonation

Many diagenetic events can be recorded in rocks as only subtle cement zones or corrosion surfaces on mineral faces. To better observe and characterize these features, Buckman and others illustrate the application of Charge Contrast Imaging (CCI) to examine diagenetic features including zoning, twinning, fractures, and geochemical changes. Applying the technique to a complex Cretaceous coquina carbonate and Devonian reef carbonate sample illustrates results comparable to SEM-Cathodoluminescence (and optical-CL), but with several advantages. 1) CCI does not suffer from image smearing, due to latency of the red light phase within CL, a different type of charge. 2) CCI typically is faster than SEM-CL. 3) CCI appears to highlight fabric and cement details within regions of carbonate that appear nonluminescent under CL. Nonetheless, as with cathodoluminescence, the specific character of CCI varies as a function of elemental composition and lattice dislocations.  

Charge contrast imaging (CCI): revealing enhanced diagenetic features of a coquina limestone by James O. Buckman, Patrick W.M. Corbett, and Lauren Mitchell

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