Geologists have long been interested in the fabric of clastic sediments and their use in the reconstruction of current direction. However, study of the fabric of argillaceous sediments has not been extensive due to their extremely fine texture and complex composition.

With advanced technology and instrumentation, particularly transmission electron microscopy (TEM) and scanning electron microscopy (SEM), a new era of clay petrology has arrived. The superior resolution, wide range of magnification, very

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great depth of field, stereo, and x-ray analysis capability affored by TEM and SEM, enable us to examine the individual clay particles by the use of ultra-thin sections (TEM), to observe the particle surface and its three dimensional structure (SEM), and to determine the clays' chemical composition.

Clay fabric from various environments, such as shallow-marine deltas, deep ocean trenches, and laboratory consolidated samples have been investigated. Clay fabric study of these sediment reveals a good correlation with their physical properties as well as depositional history. Thus, combined information of clay fabric analyses, geotechnical properties, and mineralogic data will not only be useful in reflecting different conditions of sedimentation, but will also be beneficial in depicting postdepositional history. It is the time to develop the new science of clay fabric analysis, and hope that our understanding of argillaceous sediments can be further improved by these new analytical approaches.

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