How did the Monterey shale formation originate?
The Monterey Formation is a bio-siliceous, very organic-rich deposit found in southern California. It was deposited between 17 and 5 million years ago during a time when tectonic forces were shifting, and localized subsidence during a time of high eustatic sea level, along with coastal upwelling, affected the area.
What is the method of formation for shale?
Shale is a fine-grained sedimentary rock that is formed when silt and clay are compressed. It is composed of many thin layers, and it readily splits into thin pieces where these layers meet—making it a relatively brittle stone.
When was the Monterey Formation formed?
between 16 and 6 million years ago
The Monterey Formation formed during the Miocene Epoch, between 16 and 6 million years ago, at the bottom of a green sea teeming with diatoms.
What is the importance of the Monterey Formation?
The Monterey Formation is the major source-rock for 37 to 38 billion barrels of oil in conventional traps such as sandstones. This is most of California’s known oil resources.
How deep did the Monterey Formation have to be buried to start converting the plankton biogenic component into oil?
Generation of oil began as the Monterey reached burial depths of about 12,000 ft within the last few million years. Assessment unit boundaries outline the areas where at least part of the Monterey is buried deeply enough to generate oil.
Where is the Monterey Shale?
The Monterey Shale, primarily a crude oil formation located in both onshore and offshore Southern California at depths between 8,000′-14,000′, is easily one of the most polarizing unconventional formations in North America.
In what type of depositional environment were the muds that were compressed to become the Monterey Formation deposited?
Depositional Environment. We know that deposition of the Monterey Formation occurred with a deep marine environment because of the presence of diatoms, chert, turbidites, and marine fish fossils.
Is there oil in California?
As of 2012, California was the nation’s third most prolific oil-producing state, behind only Texas and North Dakota. In the 20th century, California’s oil industry grew to become the state’s number one GDP export and one of the most profitable industries in the region.
What type of rocks make up Monterey Bay?
Basement rocks in the southern segment of the MBNMS are mainly Jurassic Franciscan melange and metamorphic rocks, Cretaceous sandstones, and carbonates of the Sur Series. Tertiary volcanic and sedimentary rocks locally overlie the basement rocks, but are not well mapped.
What formation makes up the majority of Palos Verdes?
The Altamira Shale is the oldest of three subunits of the Monterey Shale and underlies most of the area of the Palos Verdes peninsula.
How long does it take to form shale?
Shale formations are a worldwide occurrence (see Chapter 2). Shale is a geological rock formation rich in clay, typically derived from fine sediments, deposited in fairly quiet environments at the bottom of seas or lakes, having then been buried over the course of millions of years.
What is the metamorphic sequence for shale?
Different grades of metamorphism are demonstrated when a shale is subjected to increasingly greater pressure and heat – first it becomes slate, then phyllite, then schist, and finally, gneiss.