Palaeoclimate Controls on Spectral Gamma‐Ray Radiation from Sandstones

Ruffell, Alastair; Worden, Richard H.; Evans, R.

doi:10.1002/9781444304336.ch4

Cited by 9 publications

(8 citation statements)

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“…Abundant K‐feldspar overgrowths form after iron‐oxide/hydroxides and thin illitic coatings in the Skagerrak Formation during early burial. K‐feldspar is a common authigenic phase in several other continental red beds (Burley, ; Burley et al ., ; Ruffel et al ., ). This suggests that a high K + activity existed in the formation waters during early burial of sediments deposited during arid to semi‐arid conditions.…”

Section: Discussionmentioning

confidence: 97%

“…Kaolinite precipitation, promoted by meteoric water, probably occurred in fluvial, estuarine‐fluvial, lagoonal and even shoreface sandstones, if forced into the latter by a hydraulic head (Bjørlykke & Aagaard, ). Meteoric water flushing may have intensified during shoreline progradation associated with relative sea‐level falls (Burley, ; Ketzer et al ., ; Ruffel et al ., ; El‐ghali et al ., ), which occurred several time during deposition of the Gassum Formation (Nielsen, ).…”

Section: Discussionmentioning

confidence: 99%

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The influence of climate on early and burial diagenesis of Triassic and Jurassic sandstones from the Norwegian–Danish Basin

Weibel

Olivarius

Kjøller

et al. 2017

The Depositional Record

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Climate changes preserved in sandstones are documented by comparing the sediment composition and early diagenetic changes in sandstones deposited during arid to semi-arid conditions, the Skagerrak Formation, with sandstones of the Gassum Formation deposited in a humid well-vegetated environment. The study area covers the easternmost part of the Norwegian-Danish Basin, for which the Fennoscandian Shield functioned as sediment source area. The depositional environments of the formations, their distribution and burial depths are well-constrained, facilitating a comprehensive petrographical and geochemical study complemented by porosity and permeability measurements of cores widely distributed in the basin (1700 to 5900 m burial depth). The Skagerrak Formation had an immature composition with more abundant feldspar, rock fragments and a larger variability in the heavy mineral assemblage when compared to the Gassum Formation, which was characterized by quartz and more stable heavy minerals. The arid to semi-arid climate led to early oxidizing conditions under which abundant iron-oxide/hydroxide coatings formed, while the evaporative processes occasionally resulted in caliche and gypsum precipitation. Under the humid climate, kaolinite precipitated due to leaching of feldspar and mica, and the abundant organic matter caused reducing conditions, which led to other Fe-rich phases, i.e. pyrite, Fe-chlorite and siderite. The inherited early diagenetic pore fluids and mineral assemblage also affect the mineral changes occurring during deeper burial, so dolomite preferentially formed in the sandstones deposited in an arid environment, while ankerite characterizes sandstones deposited under humid conditions. In addition to climate-induced burial diagenetic changes, there are also temperature-dependent phases, such as illite and quartz cement. Despite the same sediment source area remaining active during the entire period, the sediments that reached the Norwegian-Danish Basin were immature during the arid interval, although mature during the humid period. This has implications for provenance investigations as well as diagenetic investigations of sandstone reservoir quality.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

The influence of climate on early and burial diagenesis of Triassic and Jurassic sandstones from the Norwegian–Danish Basin

Weibel

Olivarius

Kjøller

et al. 2017

The Depositional Record

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“…monazite), which may mislead log interpreters (Rider, 1990;Hurst, 1990). Outcrop gamma (total and spectral) data can been used in a variety of ways, for example: facies discrimination (Myers and Bristow, 1989;North and Boering, 1999); stratigraphic correlation (Myers and Bristow, 1989;Slatt et al, 2000); sequence stratigraphic interpretations (Van Wagoner et al, 1990;Davies and Elliott, 1996;George, 2000); clay mineralogy and palaeoclimate studies (Myers and Wignall, 1987;Ruffell et al, 2003); geochemical studies (Van Buchem et al, 1992;Svendsen and Hartley, 2001); stratabound ore-zone definition (Ruffell et al, 1998); structural correlations (Hadley et al, 2000); and to differentiate between faults and flooding surfaces (Ruffell et al, 2004). Spectral gamma ray data was measured in the Tumblagooda Sandstone, but the results will be discussed elsewhere.…”

Section: Introductionmentioning

confidence: 98%

An outcrop gamma ray study of the Tumblagooda Sandstone, Western Australia

Evans¹,

Mory²,

Tait³

2007

Journal of Petroleum Science and Engineering

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“…No distinct relationship between high U content and mudstone grainsize is seen. Ruffell et al (2003) presented a model for the flux of K, U and Th in different weathering systems at basin scale. One of their scenarios is a basin with a low-relief hinterland and a humid climate, which applies to the depositional setting of the Atane Formation.…”

Section: Spectral Gamma-ray Characterisationmentioning

confidence: 99%

Calibration of spectral gamma-ray logs to deltaic sedimentary facies from the Cretaceous Atane Formation, Nuussuaq Basin, West Greenland

2013

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Gamma-ray logs are widely used as a lithology indicator in wells as part of standard petrophysical interpretations. In cored wells, gamma-ray logs should always be calibrated to the lithology in order to correct the petrophysical model. Gamma radiation is emitted from three elements, K, Th and U (potassium, thorium and uranium) which occur in minerals such as feldspar, mica, glauconite, clay minerals, zircon, titanite and apatite as well as in organic complexes. Organicrich mudstones usually have high gamma-radiation values and quartz-rich sandstones low values. In many places, upward-coarsening successions are recognisable from the gamma log. The gamma log records the sum of radiation from K, Th and U, and their relative contributions are measured in a spectral gamma-ray log. The present case study focuses on spectral gamma-ray characterisation of the deltaic Atane Formation which shows well-developed, upward-coarsening delta-front deposits in outcrops (Fig. 1C).

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Palaeoclimate Controls on Spectral Gamma‐Ray Radiation from Sandstones

Cited by 9 publications

References 0 publications

The influence of climate on early and burial diagenesis of Triassic and Jurassic sandstones from the Norwegian–Danish Basin

The influence of climate on early and burial diagenesis of Triassic and Jurassic sandstones from the Norwegian–Danish Basin

An outcrop gamma ray study of the Tumblagooda Sandstone, Western Australia

Calibration of spectral gamma-ray logs to deltaic sedimentary facies from the Cretaceous Atane Formation, Nuussuaq Basin, West Greenland

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