@article{ChristImmenhauserAmouretal.2012,
  author    = {Christ, Nicolas and Immenhauser, Adrian and Amour, Frederic and Mutti, Maria and Tomas, Sara and Agar, Susan M. and Alway, Robert and Kabiri, Lahcen},
  title     = {Characterization and interpretation of discontinuity surfaces in a Jurassic ramp setting (High Atlas, Morocco)},
  series = {Sedimentology : the journal of the International Association of Sedimentologists},
  volume    = {59},
  journal   = {Sedimentology : the journal of the International Association of Sedimentologists},
  number    = {1},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0037-0746},
  doi       = {10.1111/j.1365-3091.2011.01251.x},
  pages     = {249 -- 290},
  year      = {2012},
  abstract  = {Discontinuity surfaces are widely recognized but often poorly understood features of epeiric carbonate settings. In sedimentary systems, these features often represent hiatus surfaces below biostratigraphic resolution and may represent a considerable portion of the time contained in the sediment record. From an applied perspective, discontinuities may represent horizontal flow barriers and result in reservoir compartmentalization. Here, a total of 80 condensed surfaces (S1), firmgrounds (S2) and hardgrounds (S3) from a Jurassic (Middle and Upper Bajocian Assoul Formation) ramp setting of the High Atlas in Morocco are carefully documented with respect to their morphology, their secondary impregnation by Fe and Mn oxides and phosphates and their palaeoecological record. A statistical frequency distribution of two surfaces of the S1 type, 1.1 surfaces of the S2 type and 0.4 surfaces of the S3 type per 10 section metres is observed along a 220 m long carbonate succession. Based on two stratigraphically and spatially separated study windows and correlative sections, the stratigraphic frequency distribution, the lateral extent and the nature of facies change across discontinuities are documented in a quantitative manner. Specific features of the study site include the considerable stratigraphic thickness of the Assoul Formation and the conspicuous absence of subaerial-exposure-related features. Based on the data presented here, firmground and hardground surfaces are best interpreted as maximum-regression-related features. Relative sea-level lowstand results in a lowered wave base, and wave orbitals and currents result in sea floor omission and lithification. Care must be taken to avoid overly simplistic interpretations, as differences in bathymetry and carbonate facies result in marked changes in discontinuity characteristics in proximal-distal transects. The data shown here are of significance for those concerned with the interpretation of shoal water carbonate environments and are instrumental in the building of more realistic carbonate reservoir flow models.},
  language  = {en}
}
@article{TomasHomannMuttietal.2013,
  author    = {Tomas, Sara and Homann, Martin and Mutti, Maria and Amour, Frederic and Christ, Nicolas and Immenhauser, Adrian and Agar, Susan M. and Kabiri, Lahcen},
  title     = {Alternation of microbial mounds and ooid shoals (Middle Jurasssic, Morocco) - response to paleoenvironmental changes},
  series = {Sedimentary geology : international journal of applied and regional sedimentology},
  volume    = {294},
  journal   = {Sedimentary geology : international journal of applied and regional sedimentology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0037-0738},
  doi       = {10.1016/j.sedgeo.2013.05.008},
  pages     = {68 -- 82},
  year      = {2013},
  abstract  = {The occurrence of neritic microbial carbonates is often related to ecological refuges, where grazers and other competitors are reduced by environmental conditions, or to post-extinction events (e.g. in the Late Devonian, Early Triassic). Here, we present evidence for Middle Jurassic (Bajocian) microbial mounds formed in the normal marine, shallow neritic setting of an inner, ramp system from the High Atlas of Morocco. The microbial mounds are embedded in cross-bedded oolitic facies. Individual mounds show low relief domal geometries (up to 3 m high and 4.5 m across), but occasionally a second generation of mounds exhibits tabular geometries (<1 m high). The domes are circular in plan view and have intact tops, lacking evidence of current influence on mound preferred growth direction or distribution patterns, or truncation. The mound fades consists almost entirely of non-laminated, micritic thrombolites with branching morphologies and fine-grained, clotted and peloidal fabrics. Normal marine biota are present but infrequent. Several lines of evidence document that microbial mound growth alternates with time intervals of active ooid shoal deposition. This notion is of general significance when compared with modern Bahamian microbialites that co-exist with active sub-aquatic dunes. Furthermore, the lack of detailed studies of Middle Jurassic, normal marine shallow neritic microbial mounds adds a strong motivation for the present study. Specifically, Bajocian mounds formed on a firmground substratum during transgressive phases under condensed sedimentation. Furthermore, a transient increase in nutrient supply in the prevailing mesotrophic setting, as suggested by the heterotrophic-dominated biota, may have controlled microbial mound stages.},
  language  = {en}
}