Origin of lamination in deep sea, fine-grained sediments

Stow, Dorrik; Bowen, Anthony

doi:10.1038/274324a0

Cited by 88 publications

(39 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, the defmi tions and criteria to recognise contourites were estab lished by Stow (1977Stow ( , 1982, Stow and Bowen (1978), Stow and Lovell (1979), Lovell and Stow (1981), Stow et al (1986) and by the papers compiled in a special issue edited by Stow and Piper (1984a). Many of these papers deal with the problem of distinguishing fine grained turbidites from contourites.…”

Section: Discussionmentioning

confidence: 99%

Mid-depth calcareous contourites in the latest Cretaceous of Caravaca (Subbetic Zone, SE Spain). Origin and palaeohydrological significance

Martı́n-Chivelet

Fregenal-Martı́nez

Chacón

2003

Sedimentary Geology

View full text Add to dashboard Cite

Deep marine carbonates of Late Campanian to Early Maastrichtian age that crop out in the Subbetic Zone near Caravaca (SE Spain) contain a thick succession of dm-scale levels of calcareous contourites, alternating with fine-grained pelagitesl hemipelagites. These contourites, characterised by an abundance and variety of traction structures, internal erosive surfaces and inverse and nOlmal grading at various scales, were interpreted as having been deposited under the influence of relatively deep ocean CUlTents. Based on these contourites, a new facies model is proposed.The subsurface currents that generated the contourites of Caravaca were probably related to the broad circumglobal, equatorial current system, the strongest oceanic feature of Cretaceous times. These deposits were formed in the mid-depth (200-600 m), hemipelagic environments at the ancient southern margin of Iberia. This palaeogeographic setting was susceptible to the effects of these currents because of its position close to the narrowest oceanic passage, through which the broad equatorial cun'ent system flowed in the westemmost area of the Tethys Seaway. Regional uplift, related to the onset of convergence between Iberia and Africa, probably favoured the generation of the contourites during the Late Campanian to the Early Maastrichtian.

show abstract

Section: Discussionmentioning

confidence: 99%

Mid-depth calcareous contourites in the latest Cretaceous of Caravaca (Subbetic Zone, SE Spain). Origin and palaeohydrological significance

Martı́n-Chivelet

Fregenal-Martı́nez

Chacón

2003

Sedimentary Geology

View full text Add to dashboard Cite

show abstract

“…Organoporosity is by no means the only porosity within shales, nor is Ar-ion milling the only way to image pores in shales. [13] have identified the following pore types using FESEM and standard SEM techniques [4] porous floccules which appear similar to laboratory-induced floccules (Figures 2A -F), (2) porous fecal pellets, with as much as 15% micro-porosity, (3) fossil fragments such as Tasminites spores ( Figure 4A), sponge spicules whose original, hollow central chambers may be partially or completely preserved after burial ( Figures 1B, 4B, 4C), coccospheres and their spines, who's chambers are also hollow and often open ( Figures 4D, 4E), and foraminifera with open chambers ( Figure 4F) (4) mineral grains such as pyrite framboids ( Figure 5B); (5) microchannels within shale matrix which probably are either micro-burrows and/or bounding surfaces of scours or micro-sedimentary structures (Figures 1D, 1E); and (6) fractures which occur at micron and larger scales ( Figure 5D) [13]. Some of these pore types -such as floccules which are common in many shales ( Figure 2) [4,13] -are probably at least as important as organo-porosity in storing and providing migration pathways for hydrocarbon molecules.…”

Section: Shale Porosity and Permeabilitymentioning

confidence: 99%

“…From these and other studies, a list of potential transport, deposition, and reworking processes include (in addition to hemipelagic rain): (1) hyperpycnal flows [5,8,11,12], (2) turbidity current flows, (3) tempestites (storm deposits) and wave-reworked deposits [6]; and (4) contourites (bottomhugging slope, oceanic currents) [2]. In order for claysized particles to move along the sea floor by tractive processes, as evidenced by the sedimentary structures, they must behave in a hydraulically similar manner to coarser grains.…”

Section: Shale Depositional Processesmentioning

confidence: 99%

“…Many shales exhibit mm/cm-scale cross-and parallel-laminations, scour surfaces, particle alignment parallel to bedding planes, and burrows [2][3][4][5][6][7] (Figure 1). Some shales reveal a systematic finingupward or coarsening-upward, followed by fining-upward grain-size pattern [8] while others display a systematic stacking pattern of lithofacies that indicate tempo- Thin section photomicrograph of a graded, spiculite mudstone from lamination shown in A. C. Laminations within cored interval.…”

Section: Shale Depositional Processesmentioning

confidence: 99%

See 1 more Smart Citation

Important geological properties of unconventional resource shales

Slatt

2011

Open Geosciences

View full text Add to dashboard Cite

Abstract:The revelation of vast global quantities of potentially productive gas and oil-prone shales has led to advancements in understanding important geological properties which impact reservoir performance. Based upon research on a variety of shales, several geological properties have been recognized as being common and important to hydrocarbon production.(1) transport/depositional processes include hemipelagic 'rain', hyperpycnal flows, turbidity current flows, tempestites , wave-reworking, and contour currents in both shallow and deep water settings. (2) Common shale minerals include clays, quartz, calcite, dolomite, apatite, and pyrite; organic constituents include spores (Tasmanites), plant remains, biogenic quartz and calcite, and arenaceous foraminifera. (3) Porosity and permeability are characteristically low with pore sizes ranging down to the nanoscale. Main pore types include intergranular (including pores within clay floccules), porous organic matter, porous fecal pellets, and microfractures. (4) Important geochemical characteristics include organic richness (>3%), maturity (>1.1%Ro for shale gas and 0.6-0.9% for shale oil) and type (I-IV), in addition to certain biomarkers which are indicators of bottom water oxicity during deposition. Remaining hydrocarbon potential [RHP = (S1 + S2)/TOC] also reflects temporal environmental changes. 'Isotopic reversals' can be used to detect best producing areas in shale-gas plays. (5) Lithofacies stacking patterns and sequence stratigraphy are the result of eustatic depositional history. A general sequence stratigraphic model is presented here that highlights this commonality. (6) Geomechanical properties are key to drilling, fracturing and production of hydrocarbons. Brittle-ductile couplets at several scales occur in shale sequences. (7) Geophysical properties, when calibrated to rock properties, provide a means of regionally to locally mapping the aforementioned properties. (8) Economic and societal considerations in the exploration and development of resource shales are garnering attention. Many potentially economic shale-gas and shale-oil plays are being identified globally. Risks and uncertainties associated with gas-and oil-rich shales include the lack of long-term production histories, environmental concerns related to hydraulic fracturing, uncertainty in calculating hydrocarbons-in-place, and fluctuations in supply, demand, and price.

show abstract

“…At a larger, m+ scale, their grain size may be vertically homogenous, suggestive of either hemipelagic rain or complete bioturbation, or they may reveal fining upward patterns typical of mud turbidites [8][9][10] or coarseningupward, then fining-upward patterns which, according to Mulder and others [11], are the product of deposition from hyperpycnal flows [12][13][14]. At a still larger parasequence to sequence scale, they may display systematic stacking patterns of lithofacies [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Shale depositional processes: Example from the Paleozoic Barnett Shale, Fort Worth Basin, Texas, USA

Abouelresh¹,

Slatt

2011

Open Geosciences

View full text Add to dashboard Cite

A long held geologic paradigm is that mudrocks and shales are basically the product of 'hemipelagic rain' of silt-and/or clay-sized, detrital, biogenic and particulate organic particles onto the ocean floor over long intervals of time. However, recently published experimental and field-based studies have revealed a plethora of microsedimentary features that indicate these common fine-grained rocks also could have been transported and/or reworked by unidirectional currents. In this paper, we add to this growing body of knowledge by describing such features from the Paleozoic Barnett Shale in the Fort Worth Basin, Texas, U.S.A. which suggests transport and deposition was from hyperpycnal, turbidity, storm and/or contour currents, in addition to hemipelagic rain. On the basis of a variety of sedimentary textures and structures, six main sedimentary facies have been defined from four 0.3 meter intervals in a 68m (223 ft) long Barnett Shale core: massive mudstone, rhythmic mudstone, ripple and low-angle laminated mudstone, graded mudstone, clay-rich facies, and spicule-rich facies. Current-induced features of these facies include mm-to cmscale cross-and parallel-laminations, scour surfaces, clastic/biogenic particle alignment, and normal-and inverse-size grading. A spectrum of vertical facies transitions and bed types indicate deposition from waxing-waning flows rather than from steady 'rain' of particles to the sea floor. Detrital sponge spicule-rich facies suggests transport to the marine environment as hypopycnal or hyperpycnal flows and reversal in buoyancy by transformation from concentrated to dilute flows; alternatively the spicules could have originated by submarine slumping in front of contemporaneous shallow marine sponge reefs, and then transported basinward as turbidity current flows. The occurrence of dispersed biogenic/organic remains and inversely size graded mudstones also support a hyperpycnal and/or turbidity flow origin for a significant part of the strata. These processes and facies reported in this paper are probably present in other organic-rich shales.

show abstract

Origin of lamination in deep sea, fine-grained sediments

Cited by 88 publications

References 20 publications

Mid-depth calcareous contourites in the latest Cretaceous of Caravaca (Subbetic Zone, SE Spain). Origin and palaeohydrological significance

Mid-depth calcareous contourites in the latest Cretaceous of Caravaca (Subbetic Zone, SE Spain). Origin and palaeohydrological significance

Important geological properties of unconventional resource shales

Shale depositional processes: Example from the Paleozoic Barnett Shale, Fort Worth Basin, Texas, USA

Contact Info

Product

Resources

About