Miocene reef carbonates of Mariana Islands

Conference · Fri Jan 01 00:00:00 EST 1988

OSTI ID:6143700

Siegrist, Jr, H G

Miocene carbonates in the southern Mariana Islands are impressive for their lithologic diversity, thicknesses (over 250 m), and geographic extend (>20% combined outcrop coverage over four major high islands: Guam, Rota, Tinian and Saipan). Sections are dominated either by lagoonal algal-foraminiferal wackestones and mudstones with locally abundant high-energy shelly-skeletal facies, or by rubbly to muddy, fore-reef-to-bank deposits of packstones and grainstones with highly diverse and variable biogenic clasts. Fresh to deeply weathered volcaniclastic material may comprise at least 80% of some high-energy fore-reef facies, whereas lagoonal and bank deposits usually contain less than 0.5% terrigenous material. Surprisingly, the Miocene in the Marianas lacks almost completely any reef-core facies. Several poorly developed coral-rich mounds on Saipan and localized laminated red algal buildups on Guam appear to constitute the extant reef-wall facies in the Miocene. The lack of buildups may be a matter of differential survival; it may result from headland erosion and benching associated with emergency of narrow reef tracts as has been postulated by others for south Guam. Radiometric age dating of these reef carbonates has proven unsuccessful because pervasive diagenesis has transformed the entire Miocene section into low-magnesium calcite with minor and occasional dolomite. Freshwater phreatic diagenesis accounts for the principal porosity variation and trace element distribution.

• OSTI ID: 6143700
• Report Number(s): CONF-880301-
• Resource Relation: Conference: Annual meeting of the American Association of Petroleum Geologists, Houston, TX, USA, 20 Mar 1988
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
CARBONATE ROCKS
GEOLOGIC HISTORY
MARIANA ISLANDS
PETROLEUM GEOLOGY
NATURAL GAS DEPOSITS
PETROLEUM DEPOSITS
REEFS
BIOGEOCHEMISTRY
CALCITE
CATAGENESIS
EXPLORATION
ISOTOPE DATING
LITHOLOGY
MAGNESIUM COMPOUNDS
MIOCENE EPOCH
AGE ESTIMATION
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CENOZOIC ERA
CHEMISTRY
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGY
ISLANDS
MINERAL RESOURCES
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
TERTIARY PERIOD
TRUST TERRITORY OF THE PACIFIC ISLANDS
USA
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration