Writing an abstract‘A partial biography of the writer is given. The inadequate abstract is discussed. What should be covered by an abstract is considered. The importance of the abstract is described. Dictionary definitions of “abstract” are quoted. At the conclusion a revised abstract is presented.’

The inadequate abstract is illustrated above. The passive voice is positively screaming at the reader! It is an outline, with each item in the outline expanded into a sentence. The reader is told what the paper is about, but not what it contributes. Such abstracts are merely overgrown titles. They are produced by writers who are either (1) beginners, (2) lazy, or (3) have not written the paper yet. - Landes (1966)

A proper abstract

‘The abstract is of utmost importance, for it is read by 10 to 500 times more people than hear or read the entire article. It should not be a mere recital of the subjects covered. Expressions such as “is discussed” and “is described” should never be included! The abstract should be a condensation and concentration of the essential information in the paper.’

Correlating surface & subsurface features Joints form in the ‘near-surface’ environment,

within the top 3 km Joint data may be collected from subsurface,

where fractures are evident in core. However, joints are rarely recovered in vertical cores.

If we rely on surface exposures for information about joint characteristics, we have to evaluate how good a correlation exists between subsurface and surface exposures.

Displacement Framework

Plume structures form through extension perpendicular fracture walls

Most joints are therefore extension fractures

Discernable Discernable separationseparation

No discernable No discernable separationseparation

Stylolites:Most common in carbonates

Joints and shear fractures Restricted to material with a high level of

cohesion: unlithified clay layers can sustain fractures; unlithified sand cannot

High porosity, less cohesive material may fail through the formation of shear deformation bands

These distinctions are most important in the shallow crust; porosity is progressively destroyed with increasing depth (confining pressure)

Shear fractures & deformation bandsLow porosity geomaterials High porosity geomaterials

Dunn et al. (1973)

Shear fractures & deformation bands Do not typically form the distinctive

systems exhibited by joints Most common in proximity to faults and in

fold hinges, where they exhibit regular orientations (e.g., Riedel shears)