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Titolo:
Systematic destruction of K-feldspar in deeply buried rift and passive margin sandstones
Autore:
Wilkinson, M; Milliken, KL; Haszeldine, RS;
Indirizzi:
Univ Edinburgh, Grant Inst, Dept Geol & Geophys, Edinburgh EH9 3JW, Midlothian, Scotland Univ Edinburgh Edinburgh Midlothian Scotland EH9 3JW Midlothian, Scotland Univ Texas, Dept Geol Sci, Austin, TX 78713 USA Univ Texas Austin TX USA 78713 Texas, Dept Geol Sci, Austin, TX 78713 USA
Titolo Testata:
JOURNAL OF THE GEOLOGICAL SOCIETY
, volume: 158, anno: 2001,
parte:, 4
pagine: 675 - 683
SICI:
0016-7649(200107)158:<675:SDOKID>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
MEXICO SEDIMENTARY BASIN; OLIGOCENE FRIO FORMATION; TERTIARY VOLCANIC-ROCKS; GULF-COAST SHALES; NORTH-SEA; SOUTH TEXAS; SECONDARY POROSITY; ALUMINUM LOSS; DETRITAL FELDSPARS; POTASSIUM CONTENT;
Keywords:
feldspar; sandstone; diagenesis; secondary porosity; compaction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Wilkinson, M Univ Edinburgh, Grant Inst, Dept Geol & Geophys, Edinburgh EH9 3JW, Midlothian, Scotland Univ Edinburgh Edinburgh Midlothian Scotland EH9 3JW cotland
Citazione:
M. Wilkinson et al., "Systematic destruction of K-feldspar in deeply buried rift and passive margin sandstones", J GEOL SOC, 158, 2001, pp. 675-683

Abstract

Systematic patterns of detrital K-feldspar decline with increasing burial depth are revealed during deep burial (1.5-4.5 km) of sandstones in diversesedimentary basins from three rift and two passive margin settings in the North Sea and USA Gulf Coast. K-feldspar destruction is predominantly by dissolution, though in-situ alteration to albite also occurs. Dissolution canremove up to 15% solid volume of the rock by 4.5 km, so that primary arkosic sandstones become diagenetic quartzarenites at depth, with increased secondary:primary porosity ratios. The quantity of K-feldspar destroyed duringtemperature increase is very variable: 0.05-1.0% solid volume/degreesC. Compaction continues during deep burial and petrographic textures diagnostic of secondary porosity are destroyed (so that many sandstones preserve < 10%secondary porosity). Alternative explanations for K-feldspar reduction with depth, including changes in original sediment provenance controlling the observed variation of feldspar with depth, or that source areas changed during deposition, can be refuted. Deeply buried sandstones are not reliable records of depositional composition. Exceptions to this scenario of detrital K-feldspar dissolution are noted. Proximity of K-rich evaporites, high SiO2 and K+ activity due to the breakdown of volcanic clasts or very low P-CO2 can stabilize both K-feldspar and a suite of K-rich cements.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 15:40:49