Brick-like texture and radial rays in Triassic pisolites of Lombardy, Italy: A clue to distinguish ancient aragonitic pisolites

Assereto, R.; Folk, Robert L.

doi:10.1016/0037-0738(76)90032-4

Cited by 45 publications

(12 citation statements)

References 6 publications

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“…6). These structures are almost identical to ones reported from the back-reef pisolite facies of the Permian Capitan reef complex of the southwestern United States (Dunham, 1969;Kendall, 1969;Loucks& Folk, 1976) as well as from the Triassic of the Italian Alps (Assereto & Folk, 1976;Assereto & Kendall, 1977). Although their interpretation is controversial in all those cases, it is likely that the fabrics were formed in upper intertidal to supratidal (or non-tidal) settings based on analogies to modern occurrences (Scholle & Kinsman, 1974; Handford et al, 1984).…”

Section: Sedimentation In Restricted Shelfsettings (West Of the Karstsupporting

confidence: 81%

Palaeokarst‐influenced depositional and diagenetic patterns in Upper Permian carbonates and evaporites, Karstryggen area, central East Greenland

et al. 1993

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The Karstryggen area of eastern Greenland represents the western edge of sedimentation in the Jameson Land Basin, an arm of the northern Zechstein seaway. Upper Permian strata of this area were deposited as two major sequences. The first marine incursion transgressed largely peneplaned Lower Permian strata and deposited thin, paralic conglomerates, sandstones and shales (the Huledal Formation) followed by a thick package of carbonates and evaporites (the Karstryggen Formation). Although the Karstryggen Formation represents the transgressive maximum of this sequence, it contains only marginal or restricted marine strata, including micritic, stromatolitic and peloidal carbonates and thick, but localized, bedded gypsum deposits. These lithofacies indicate that relatively arid climates prevailed in this basin, as in most of the Zechstein region. A major regression, associated with a change to a more humid climate, terminated Karstryggen sedimentation. Pre‐existing evaporites and carbonates underwent diagenetic alteration, including widespread calcitization and dissolution of gypsum. More importantly, topographic relief in excess of 120 m was generated by fluvial drainage systems and karstic sinkholes. A second marine incursion, accompanied by a return to a semi‐arid climate, drowned this high relief topography, producing a complex sequence of strata (the Wegener Halvø Formation) in which sedimentation was greatly influenced by the rugged underlying terrain. Marine cemented algal‐molluscan grainstones draped pre‐existing palaeotopography during the initial stages of flooding. Continued drowning led to differential sedimentation on ‘highs’ and in ‘lows’. Oolitic and bryozoan‐brachiopod grainstones formed as shoals on the crests of most prominences, whereas shales, conglomeratic debris flows, evaporites, or oolitic turbidites were deposited in the lows. More restricted sedimentation took place in the westernmost areas which lay closest to the mainland shoreline and were situated to the west of a palaeotopographic ridge. There, oolitic, stromatolitic and evaporitic strata were deposited under hypersaline conditions indicative of a return to more arid climatic conditions. Three subcycles mark smaller scale relative changes of sea level that occurred during deposition of the Wegener Halvø Formation; they are delimited by regional surfaces with moderate relief (5–20 m) developed during subaerial exposure. Widespread diagenetic changes, including leaching of aragonitic grains, dissolution/collapse brecciation of evaporites and meteoric calcite cementation, occurred in association with these smaller scale sequence boundaries, again reflecting climatic oscillations. Relative sea level fluctuations, coupled with regional climate changes, played a dominant role in determining both depositional and diagenetic relations in these strata. These features undoubtedly extend into subsurface parts of this basin as well as into yet unexplored areas of the northern Zechstein Basin and Barents Shelf, and may have economic signific...

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Section: Sedimentation In Restricted Shelfsettings (West Of the Karstsupporting

confidence: 81%

Palaeokarst‐influenced depositional and diagenetic patterns in Upper Permian carbonates and evaporites, Karstryggen area, central East Greenland

et al. 1993

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“…Close to the Ladinian-Carnian boundary, a major sea-level fall is recorded in the Lombardy Basin by a lithostratigraphic unit ("Calcare Rosso", Assereto and Kendall, 1977;Assereto and Folk, 1977;1980;Mutti, 1994;Berra, 2007) characterized by regressive deposits with evidence of subaerial exposures, covering the flat top of the carbonate platform of the Esino Limestone. The Calcare Rosso is thickest and well exposed in Middle Val Brembana, where it consists of up to 60 m of cyclic peritidal limestones characterized by prevailing supratidal facies and evidence of karstification associated with deposition of lenses of carbonate breccias, precipitation of early carbonate-cement and development of mature tepee and paleosols.…”

Section: Geological Settingmentioning

confidence: 99%

Large-scale progradation, demise and rebirth of a high-relief carbonate platform (Triassic, Lombardy Southern Alps, Italy)

Berra

Jadoul

Binda

et al. 2011

Sedimentary Geology

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“…(1953), Kendall (1969), Reeves (1970), Dunham (1972), Smith (1974, Assereto and Folk (1976)) and indeed nearly identical structures can be produced in a sub-aqueous environment (compare Figure 14 Shinn (1969) (1925), and Figure 8 of this paper). It seems that the main difference between calcrete pseudo-anticlines and tepees is the lack of voids and lack of an axial planar fracture in the former (Smith (1974) p. 66).…”

Section: Progressive Development Of Type 1 Calcrete Anticlines (Schemmentioning

confidence: 84%

Pseudo‐anticlines and other structures in some calcretes of Botswana and South Africa

Watts

1977

Earth Surf. Process.

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SUMMARYDeformation structures, within some Quaternary calcretes of Botswana and South Africa, have been classified into five types. Type 1 folds are small-scale ( < 2 m wavelength) anticlines in shale or sheet calcrete, separated by wedges of calcrete, polygonal in plan. The anticlines have resulted from horizontal expansion and buckling caused by the disruptive growth of the calcrete wedges. Type 2(a) folds are medium-scale, strongly convoluted features in sheet calcrete and bedrock and are attributed to the introduction of calcrete along major vertical joint planes. Type 2(b) folds are large wavelength (> 20 m), but low amplitude (< 1 m), anticlines in hardpan calcrete; structural evidence suggests dominantly horizontal compression within the hardpan due either to an overall increase in volume of the calcrete, or to the disruptive formation of calcrete in joints in the synclinal areas. The mineralogy of the calcretes is dominated by low-Mg calcite which may have inverted from a high-Mg form; the deformation in type 1 and 2 folds was probably caused by the disruptive and displacive growth of calcite during calcretization. Type 3 folds are saucer-shaped depressions in hardpan calcrete and may be due to the removal of soluble salts below the folded layer during or after calcretization. Finally, type 4 folds are small, diapiric anticlines resulting from the upward injection of swelling clays into calcrete or calcretized shale.

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Brick-like texture and radial rays in Triassic pisolites of Lombardy, Italy: A clue to distinguish ancient aragonitic pisolites

Cited by 45 publications

References 6 publications

Palaeokarst‐influenced depositional and diagenetic patterns in Upper Permian carbonates and evaporites, Karstryggen area, central East Greenland

Palaeokarst‐influenced depositional and diagenetic patterns in Upper Permian carbonates and evaporites, Karstryggen area, central East Greenland

Large-scale progradation, demise and rebirth of a high-relief carbonate platform (Triassic, Lombardy Southern Alps, Italy)

Pseudo‐anticlines and other structures in some calcretes of Botswana and South Africa

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