Open system diagenesis and the los of provenance signatures: isotopic and elemental data from sandstones, Frio Formation, south Texas

Conference · Tue May 01 00:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6677334

Land, L S; Mack, L E; Milliken, K L ^[1]; MacPherson, G L ^[2]

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1. Univ. of Texas, Austin (USA)
2. Univ. of Kansas, Lawrence (USA)

Oligocene Frio sandstones in which detrital feldspars are completely altered typically contain authigenic minerals that exceed 30% of the rock volume. Elemental and isotopic analyses of whole rocks show that authigenesis is accompanied by both gain and loss of material. Subsurface sandstones for elemental and isotopic analysis were sampled from approximately 3,000-14,000 ft (0.9-4.3 km). Over this depth range, dissolution and minor albitization of detrital K-feldspar is accompanied by loss of 2 to 3 wt.% of K{sub 2}O from the whole rock. Loss of about 50% of the initial strontium also correlates with alteration of detrital feldspars. {sup 87}Sr/{sup 86}Sr for whole-rock and silicate fractions change with depth as strontium characteristic of the detrital fraction is replaced by more radiogenic strontium derived from deeper in the basin. Aluminum, titanium, phosphorous, manganese, and barium also exhibit trends compatible with net export, but uncertainties about initial variation remain. Trends for silicon, sodium, iron, boron, and lithium are equivocal. Magnesium gain accompanies precipitation of authigenic chlorite. Whole-rock calcium values are dominated by calcite that includes both detrital and authigenic components. Significant dissolution of the detrital carbonate component does not occur, and calcium in authigenic carbonate exceeds by about five times the calcium released during destruction of detrital silicates, thus requiring considerable calcium and CO{sub 2} import. Material transfer on the scale observed suggests that simple burial diagenesis is not a closed-system process for several major elements and introduces a major obstacle to the use of elemental data for provenance interpretation.

• OSTI ID: 6677334
• Report Number(s): CONF-900605-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:5; Conference: Annual convention and exposition of the American Association of Petroleum Geologists, San Francisco, CA (USA), 3-6 Jun 1990; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
58 GEOSCIENCES
PETROLEUM DEPOSITS
RESERVOIR ROCK
DIAGENESIS
TEXAS
CARBONATE ROCKS
GEOLOGIC FORMATIONS
ISOTOPE RATIO
SANDSTONES
SEDIMENTARY BASINS
STRONTIUM 86
STRONTIUM 87
TERTIARY PERIOD
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
CENOZOIC ERA
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MINERAL RESOURCES
NORTH AMERICA
NUCLEI
RADIOISOTOPES
RESOURCES
ROCKS
SEDIMENTARY ROCKS
STABLE ISOTOPES
STRONTIUM ISOTOPES
USA
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences