Miocene reef and nonreef carbonate rocks in Japan

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

OSTI ID:6469328

Konishi, K

Japan's main islands experienced temperature climates throughout the Neogene with a tropical invasion around 16 Ma (early middle Miocene). This climatic warming, accompanied by a eustatic sea level rise, caused the unusual occurrence of reef facies, mangrove deposits, and lateritic beds in Japan. In cooler climates both before and after reef growth, sediments rich in bryozoan and algal material were widespread. Reef rocks emplaced as penecontemporaneous olistoliths in deep-water clastics at the Pacific coast of central Honshu are characterized by a wide lithologic spectrum, ranging from grainstone to bindstone. These rocks include rudstone and floatstone, which are rich in coralline algae (encrusting forms such as Lithophyllum and Mesophyllum and articulate forms such as Amphiroa) and codiacean algae (Halimeda) with hermatypic corals and large benthic formainifera (e.g., Nephrolepidina and Miogypsina) being less common. Two types of dolomite occur: (1) limpid dolomite with O/sup 18/ = -5.77 and with bipyramidal quartz and (2) microcrystalline dolomite with O/sup 18/ = 2.00 and with length-slow chalcedony. While microcrystalline dolomite tends to predominate in muddy matrix material, limpid dolomite appears to fill pores, some of which are moldic. Younger nonreef carbonate rocks, as occur on the Noto Peninsula of central Honshu, are commonly cross-bedded, contain Bryozoa, mollusks, small foraminifera, and echinoids, and are locally dolomitized. These dolomites are ascribed to a mixed-water origin. A different type of nonreef, yet reservoir-forming, dolostone occurs in the late middle Miocene of northeast Honshu and is interpreted to have formed as a transformation from bathyal opal.

• OSTI ID: 6469328
• 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
PETROGENESIS
JAPAN
PETROLEUM GEOLOGY
NATURAL GAS DEPOSITS
PETROLEUM DEPOSITS
BIOGEOCHEMISTRY
DOLOMITE
EXPLORATION
ISLANDS
REEFS
SOURCE ROCKS
TERTIARY PERIOD
ALKALINE EARTH METAL COMPOUNDS
ASIA
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CENOZOIC ERA
CHEMISTRY
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGY
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERAL RESOURCES
MINERALS
OXYGEN COMPOUNDS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration