Origin of quartz cement in the Tirrawarra Sandstone, Southern Cooper Basin, South Australia
- Univ. of Adelaide, South Australia (Australia). National Centre for Petroleum Geology and Geophysics
Quartz cement in siliciclastic sequences is commonly a major diagenetic phase that affects hydrocarbon reservoir quality. Quartz cement is the most abundant authigenic mineral in the fluvio-deltaic Tirrawarra Sandstone and plays an important role in controlling reservoir quality. Petrographic, fluid inclusion, electron microprobe and cathodoluminescence (CL) data from the quartz cement indicate multiple stages of cementation at different temperatures and suggest more than one silica source. CL observations indicate up to six stages of quartz cement in some samples. The stages of quartz cement can be classified into three zones: an innermost zone of brown-luminescing cement (Z1), a middle zone of bright blue-luminescing cement (Z2) and an outer zone of brown-luminescing cement (Z3). Dead oil or bitumen is trapped between Z2 and Z3, indicating that Z3 formed after oil migration commenced. Measurements of homogenization temperatures from fluid inclusions in quartz overgrowths indicate that quartz cement precipitated over a temperature range of 65 to 130 C. Microprobe analysis shows a consistent variation in aluminum between each quartz cement zone. Fluid-inclusion precipitation temperatures and aluminum content have been used to help identify the silica sources for different zones of cement. Considering the temperature of precipitation, very low aluminum content, and the presence of Z3 cement in facies prone to stylolitization, the silica source for the cement is likely to have been pressure solution of detrital quartz at stylolites and grain contacts.
- OSTI ID:
- 452184
- Journal Information:
- Journal of Sedimentary Research, Section A: Sedimentary Petrology and Processes, Vol. 67, Issue 1; Other Information: PBD: Jan 1997
- Country of Publication:
- United States
- Language:
- English
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