Diagenetic and petrographic trends and development of secondary porosity in Upper Cretaceous feldspathic sandstones: central Sacramento basin

Conference · Tue Mar 01 00:00:00 EST 1988 · AAPG Bull.; (United States)

OSTI ID:6633960

Mertz, Jr, K A

Upper Cretaceous Forbes sandstones from the Sutter Buttes and Rumsey Hills areas of the Sacramento basin are compositionally and texturally immature, and have undergone significant burial diagenesis and selective development of secondary porosity. Analyses reveal sequential diagenetic events that can be divided into four primary zones. Zone 1 includes early events: (a) development of clay rims on framework constituents; (b) extensive mechanical compaction, which continues into deeper burial; and (c) early diagenetic dissolution of unstable framework components and selective replacement by illitic clays and/or calcite. Zone 2 represents a period of widespread cementation: (a) precipitation of K-feldspar and quartz overgrowths; (b) generation of intergranular ferroan calcite (or, locally, siderite) and mixed-layer illite-smectite (approximately 40-60% illite); and (c) albitization of K-feldspar (plus albite overgrowths). In zone 3, extensive dissolution and local development of secondary porosity occurred. Zone 4 reveals porosity-occluding diagenetic products associated with zone 3 leaching, such as kaolinite, chlorite, pyrite, calcite, and zeolites (e.g., heulandite, analcite), and indicates continued albitization of K-feldspar. Development of secondary porosity is highly localized within given reservoir units, ranging from extensively leached zones to areas where leaching is minimal (or where late-stage carbonate cements occlude porosity). Porosity enhancement is linked to kerogen decarboxylation processes and continues during catagenesis. Diagenetic relationships suggest that most samples have not experienced temperatures in excess of 140/sup 0/-160/sup 0/C. Modal data coincide closely with other Upper Cretaceous sandstones sources primarily from the Cordilleran magmatic-arc system to the east and northeast (dissected arc sandstones; plutonic-volcanic source).

• Research Organization: Miami Univ., Oxford, OH (USA)
• OSTI ID: 6633960
• Report Number(s): CONF-8804144-
• Journal Information: AAPG Bull.; (United States), Vol. 72:3; Conference: AAPG SEPM-SEG Pacific Section and SPWLA annual convention, Santa Barbara, CA, USA, 17 Apr 1988
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
CALIFORNIA
PETROLEUM DEPOSITS
RESERVOIR ROCK
POROSITY
CRETACEOUS PERIOD
DIAGENESIS
FELDSPARS
GEOLOGIC FORMATIONS
QUARTZ
SANDSTONES
CHALCOGENIDES
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC DEPOSITS
MESOZOIC ERA
MINERAL RESOURCES
MINERALS
NORTH AMERICA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SILICON COMPOUNDS
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USA
020200* - Petroleum- Reserves
Geology
& Exploration