Large Thin Slicing: A New Method for the Study of Fabrics in Lithified Sediments

Garton, Michael; McIlroy, Duncan

doi:10.2110/jsr.2006.111

Cited by 6 publications

(2 citation statements)

References 19 publications

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“…This technique facilitated the detailed study of sedimentary fabrics that are often difficult to discern in outcrops. See Garton & McIlroy (2006) for a full description of this technique. Large thin sections were especially useful to document the ‘patchy’ texture seen in Cs7 sandstones, which had previously been problematic to capture using optical or SEM images that produced highly irregular vertical grain‐size trends.…”

Section: Methodsmentioning

confidence: 99%

Can liquefied debris flows deposit clean sand over large areas of sea floor? Field evidence from the Marnoso‐arenacea Formation, Italian Apennines

Talling¹,

Malgesini²,

Felletti

2012

Sedimentology

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The Marnoso‐arenacea Formation in the Italian Apennines is the only ancient rock sequence where individual submarine sediment density flow deposits have been mapped out in detail for over 100 km. Bed correlations provide new insight into how submarine flows deposit sand, because bed architecture and sandstone shape provide an independent test of depositional process models. This test is important because it can be difficult or impossible to infer depositional process unambiguously from characteristics seen at just one outcrop, especially for massive clean‐sandstone intervals whose origin has been controversial. Beds have three different types of geometries (facies tracts) in downflow oriented transects. Facies tracts 1 and 2 contain clean graded and ungraded massive sandstone deposited incrementally by turbidity currents, and these intervals taper relatively gradually downflow. Mud‐rich sand deposited by cohesive debris flow occurs in the distal part of Facies tract 2. Facies tract 3 contains clean sandstone with a distinctive swirly fabric formed by patches of coarser and better‐sorted grains that most likely records pervasive liquefaction. This type of clean sandstone can extend for up to 30 km before pinching out relatively abruptly. This abrupt pinch out suggests that this clean sand was deposited by debris flow. In some beds there are downflow transitions from turbidite sandstone into clean debrite sandstone, suggesting that debris flows formed by transformation from high‐density turbidity currents. However, outsize clasts in one particular debrite are too large and dense to have been carried by an initial turbidity current, suggesting that this debris flow ran out for at least 15 km. Field data indicate that liquefied debris flows can sometimes deposit clean sand over large (10 to 30 km) expanses of sea floor, and that these clean debrite sand layers can terminate abruptly.

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Section: Methodsmentioning

confidence: 99%

Can liquefied debris flows deposit clean sand over large areas of sea floor? Field evidence from the Marnoso‐arenacea Formation, Italian Apennines

Talling¹,

Malgesini²,

Felletti

2012

Sedimentology

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“…Using the pioneering work of ichnologists such as Rudolf Richter, Adolf Seilacher, Walter H€ antzschel, and Robert Frey as a foundation, ichnologists have strived to understand and visualize the character of trace fossils in two-and threedimensions (2D and 3D). Several approaches have successfully addressed this problem, including: (1) resin-casting of modern burrow networks (Shinn, 1968;Pemberton et al, 1976;Gingras et al, 2002a;Seike et al, 2012), (2) radiographs of bioturbation in soft sediments (Howard, 1968;Howard and Frey, 1973;Migeon et al, 1999), and (3) serial grinding and slabbing of rock or sediment (Genise and Laza, 1998;Garton and McIlroy, 2006;Naruse and Nifuku, 2008;Bednarz and McIlroy, 2009). …”

Section: Introductionmentioning

confidence: 99%

Associating X-Ray Microtomography with Permeability Contrasts in Bioturbated Media

Baniak

Croix

Polo

et al. 2014

Ichnos

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The use of X-ray microtomography (micro-CT) to evaluate the contrasts in permeability associated with bioturbation in twoand three-dimensions (2D and 3D) is investigated in this article. Core analysis, spot-permeametry measurements, and petrographic thin-sections of the six different datasets from Western Canada (Debolt Formation, Wabamun Group, and Medicine Hat Member) and offshore Norway (Ula Formation, Lysing Formation, and Nise Formation) show that the trace fossils commonly modify the permeability and porosity of the reservoir through sediment reworking and diagenesis of the sediment. In this study, micro-CT techniques are used to analyze the X-ray attenuation associated with bioturbation in siliciclastics and carbonates. Because X-ray attenuation represents the transmissivity or absorptivity of a sample to the incident X-rays, each of which is related to sediment composition and sediment densities, micro-CT images are integrated with sedimentological data and petrographic data to identify the trace fossils and matrix in 2D and 3D. Due to the difference in sediment grain size and sorting (i.e., porosity) within the burrows and matrix, analysis of the X-ray attenuations allows for their delineation in 2D cross-sectional images. When processed as 3D volumes, the micro-CT images show the complexity in burrow connectivity and burrow orientations within a sample. More importantly, the 3D volumes help show the distribution of porosity that can be linked to measured permeability values within a sample. Quantification of the heterogeneous burrow fabric on reservoir and resource quality is made from these processed micro-CT images.

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Methodology in Ichnological Core Logging

Knaust

2017

Atlas of Trace Fossils in Well Core

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Large Thin Slicing: A New Method for the Study of Fabrics in Lithified Sediments

Cited by 6 publications

References 19 publications

Can liquefied debris flows deposit clean sand over large areas of sea floor? Field evidence from the Marnoso‐arenacea Formation, Italian Apennines

Can liquefied debris flows deposit clean sand over large areas of sea floor? Field evidence from the Marnoso‐arenacea Formation, Italian Apennines

Associating X-Ray Microtomography with Permeability Contrasts in Bioturbated Media

Methodology in Ichnological Core Logging

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