The links between depositional fabrics, diagenesis and fracture patterns
are explored for the Barremian-Aptian Jurf and Qishn formations of central
east Oman. Field, petrographic and analytical (oxygen and carbon isotopic
ratios, clumped isotopes, strontium isotopes, major and trace elements, tensile
strength) data were acquired. The excellent outcrop exposures allow
the investigation of the geometries, dimensions and spatial distributions of
sedimentary bodies, diagenetic bodies and fractures at the inter-well scale
(one kilometre). It is suggested that in the Late Barremian, storm and wave
reworking and transport were the dominant sedimentary processes operating
in the peritidal environment of the southern Tethyan platform. The stratigraphic
distribution of the parasequences and discontinuity surface types
suggest some regional sea level control on the peritidal carbonate cyclicity.
Pervasive dolomite is restricted to the Jurf Formation transgressive systems
tract, which is characterized by a peritidal environment rich in microbial
mats. Other system tracts, despite being composed of peritidal facies with
evidence for high salinities, were not dolomitized, suggesting that the presence
of microbial mats, i.e. the depositional fabric, exerted a major control
on dolomite distribution. Spacing and orientation of fractures in limestones
also depend strongly on the depositional fabric. Grain-supported facies, such
as grainstones and rudstones, develop closely and evenly spaced northwestsoutheast
oriented stratabound fractures; whereas mud-supported facies develop
widely and unevenly spaced throughgoing fractures predominantly oriented
north-south. It is suggested that fractures developed until fracture saturation
in early cemented grain-supported facies during the Late Cretaceous.
As burial increased, the bedding interfaces become stronger allowing for the
development of throughgoing fractures that cross-cut mud-supported beds,
which remained undersaturated with respect to fractures. This study shows
that diagenetic heterogeneities of the Jurf and Qishn formations are strongly
linked to depositional heterogeneities, and that both the depositional fabric
and early diagenesis control the distribution of fracture heterogeneities.