Quantifying the geometry and sediment fabric of linear slopes: examples from the Tertiary of Italy (Southern Alps and Gargano Promontory)

Adams, Erwin W.; Morsilli, Michele; Schlager, Wolfgang; Keim, Lorenz; Hoek, Tomas van

doi:10.1016/s0037-0738(02)00125-2

Cited by 15 publications

(16 citation statements)

References 20 publications

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“…The nummulite bank facies is located in the uppermost portion of the ‘Calcareniti nummulitiche di Monte Saraceno’ (Fig. 2) and corresponds to ‘Facies 2’ (skeletal packstones and rudstones) of Adams et al. (2002).…”

Section: Geological Settingmentioning

confidence: 99%

Automicrite in a ‘nummulite bank’ from the Monte Saraceno (Southern Italy): evidence for synsedimentary cementation

Guido¹,

Papazzoni

Mastandrea³

et al. 2010

Sedimentology

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Following introduction of the term 'nummulite bank', there has been debate regarding interpretation of these types of deposits as autochthonous (automicrite) or allochthonous (detrital micrite). These banks are made up of large foraminifera and ill-defined fine-grained components. The fine-grained components consist mainly of micrites. The recognition of automicrite has deep implications for the synsedimentary cementation and stabilization of the bank. In order to distinguish between automicrite and detrital micrite, the nanomorphology, geochemistry and organic matter remains in the microfacies of a nummulite bank in the Middle Eocene of Monte Saraceno (Gargano, Southern Italy) were analysed. Optical and scanning electron microscope investigations showed that the micrites have been recrystallized to aggrading microsparite. Epifluorescence observations on selected micrite/microsparite areas with peloidal texture revealed the presence of organic matter. Scanning electron microscope analyses on epifluorescent micrites showed that the microbial peloids have smaller crystal sizes than those in organic matterdepleted areas. The geochemical characterization of extracted organic matter, performed through the functional group analyses by Fourier transform-infrared spectroscopy, shows strong prevalence of the aromatic fraction over the aliphatic and carboxylic ones. These characteristics of organic compounds indicate both their thermal maturation and their likely derivation from degradation of bacterial communities. The local presence of peloidal antigravity textures, bright epifluorescence and organic molecules in clotted peloidal areas suggest that the metabolic activity of microbial communities could have induced precipitation of these micrites and, consequently, the syndepositional cementation of the nummulite bank. This type of cementation can rapidly stabilize sediments and promote the depositional bank geometry.

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Section: Geological Settingmentioning

confidence: 99%

Automicrite in a ‘nummulite bank’ from the Monte Saraceno (Southern Italy): evidence for synsedimentary cementation

Guido¹,

Papazzoni

Mastandrea³

et al. 2010

Sedimentology

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“…Slope angles consistently range between 35 • and 40 • . Slope beds, with a metre-scale thickness, have a planar geometry interpreted to represent the angle of repose (Adams et al, 2002). The upper slope contains both reworked and in situ laminar stromatoporoids.…”

Section: Slope Environmentmentioning

confidence: 99%

“…Sediment transport also occurs if the dip of the slope at which the sediments rest becomes higher than the angle of repose. We used an angle of repose of 35 • for both types of unconsolidated sediment because both types are non-cohesive and have a sand-sized grain size (Kenter, 1990;Adams et al, 2002).…”

Section: Sediment Transportmentioning

confidence: 99%

Fine‐Scale Forward Modelling of a Devonian Patch Reef, Canning Basin, Western Australia

Hasler

Adams

Woods

et al. 2008

Analogue and Numerical Modelling of Sedimentary Systems: From Understanding to Prediction

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Although factors that control the distribution of carbonate sediments are relatively well understood, their interaction in producing known geometries remains poorly known. A fine-scale forward model was developed to analyse the controls on decimetre-scale heterogeneity and carbonate facies distribution within larger-scale sediment bodies. The model was tested on a Frasnian (Late Devonian) patch reef, part of the so-called Glenister Knolls reef complex in the Canning Basin, Western Australia. The evolution of Glenister Knolls was digitally reconstructed using digital surveying technologies that resulted in a high-resolution dataset containing geological information from centimetrescale to outcrop dimensions. The three-dimensional digital outcrop model of Glenister Knolls was used to evaluate predictions from the fine-scale forward modelling results.The fine-scale forward model is based on a stochastic cellular automaton that simulates the spatial distribution of carbonate facies through time. The modelled carbonate facies is based on two main factors, stromatoporoid growth and sediment transport, and it successfully predicts the distribution of the basic elements -reef fabric and sediment -that compose the patch reef. The fine-scale forward model also successfully reproduces all major depositional relationships observed in the field such as backstepping, downlapping and interfingering contacts. The external structure of the reef is very sensitive to subsidence and production rates, since these directly influence accommodation space so constraining the vertical growth of the patch reef. However, the internal structure predicted by this model does not seem to be affected by one specific parameter, and displays the same sensitivity to other parameters, such as current intensity and wave amplitude.

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Section: Introductionmentioning

confidence: 99%

“…Dynamics of platform shedding and progradation were analysed in the geological literature in terms of: (i) slope geometry; (ii) stratigraphic architecture of the prograding succession; and (iii) processes of sediment production and transport along the slope and to the basin. The geometry of carbonate clinoforms was investigated in detail (Bosellini, 1984;Doglioni & Bosellini, 1989;Adams et al, 2002) and controlling parameters of clinoform declivity, such as sediment mineralogy, fabric and facies, were identified (Kenter & Schlager, 1989;Kenter, 1990). Seismic (Eberli & Ginsburg, 1989) and outcrop data (Pomar, 1991;Booler & Tucker, 2002) improved the interpretation of the stratigraphic architecture of slope successions in terms of sequence stratigraphy and highlighted the superposition of sea-level fluctuations with different frequencies.…”

Section: Introductionmentioning

confidence: 99%

Compositional changes in sigmoidal carbonate clinoforms (Late Tithonian, eastern Sardinia, Italy): insights from quantitative microfacies analyses

Lanfranchi¹,

Berra²,

Jadoul³

2011

Sedimentology

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Quantitative analysis of sediment composition was performed on a kilometre wide section of Upper Tithonian low relief (up to 70 m), gently inclined (3° to 15°), sigmoidal carbonate clinoforms (eastern Sardinia) to identify changes in sediment composition along the slope and across the studied succession. These changes may reflect modifications of the carbonate factory and of processes responsible for sediment transport. Point‐count analysis of carbonate microfacies, Q‐mode/R‐mode cluster analysis and Spearman’s rank provided a composition‐based classification of microfacies and highlighted relationships among sediment components. The studied clinoforms are mainly composed of non‐skeletal grains (70%), such as peloids and lithoclasts, together with micrite and cements and only a limited contribution from coated grains (2%). Among skeletal grains (28%), the greatest contribution derives from a coral–stromatoporoid–encruster reef that provided 15% of the components. Crinoids, brachiopods and other along‐slope thriving biota provided nearly 5% of the allochems, whilst fragments of molluscs (gastropods, bivalves and diceratids) from the backreef sourced another 2%. The contribution of platform interior biota is negligible (1%). The association of composition‐based facies varies along the slope. The upper slope beds consist of coral‐stromatoporoid grainstone to rudstone; the middle slope deposits are dominated by encruster‐lithoclast grainstone and packstone. At the lower slope, peloidal lithoclastic packstone as well as brachiopod–crinoidal wackestone prevail. Also the association of skeletal grains changes along the slope. The encruster–frame builder association typifies the upper slope whilst encrusters characterize the middle slope sediments. In the lower slope encrusters are equally represented as the brachiopod–crinoid association. Along‐slope compositional changes evidence a scarce downslope transport of frame builders and a progressive enrichment in along‐slope thriving biota. Quantitative analysis of microfacies allowed the sigmoidal clinoforms to be grouped into six sets. Each set gathers sigmoids with a similar sediment composition. Coated grains are dominant in the first set whilst they are lacking in the overlying sets reflecting a change in the carbonate factory. Other major compositional changes among the sets concern the relative amounts of peloids, micrite, frame builders (corals and stromatoporoids) and encrusters. The contribution of peloids varies inversely to that of cements and micrite as evidenced in the third and fifth sets which, respectively, record the highest occurrence of peloids or cement and micrite. Variations in the amount of frame builders and encrusters are instead non‐linear. High percentages of both frame builders and encrusters, as recorded in the second and fifth sets, are related to low amounts of peloids and lithoclasts that probably reflect episodes of reduced background sedimentation. This study demonstrates that quantitative analysis of carbonate microfacies represen...

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Quantifying the geometry and sediment fabric of linear slopes: examples from the Tertiary of Italy (Southern Alps and Gargano Promontory)

Cited by 15 publications

References 20 publications

Automicrite in a ‘nummulite bank’ from the Monte Saraceno (Southern Italy): evidence for synsedimentary cementation

Automicrite in a ‘nummulite bank’ from the Monte Saraceno (Southern Italy): evidence for synsedimentary cementation

Fine‐Scale Forward Modelling of a Devonian Patch Reef, Canning Basin, Western Australia

Compositional changes in sigmoidal carbonate clinoforms (Late Tithonian, eastern Sardinia, Italy): insights from quantitative microfacies analyses

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