Changes

==Depositional environments and facies analysis==

==Depositional environments and facies analysis==

Most fossil species required specific conditions of temperature, [[Wikipedia:Substrate (biology)|substrate]], and surrounding medium to carry on their normal activities. When conditions differed from ideal, the species is not present or is not preserved. The types of sedimentary rocks deposited under specific environmental conditions are ''[[biofacies]]'' and are identified by their specific rock properties including fossils.<ref name=pt05r140>Scholle, P. A., Spearing, D., 1982, Sandstone depositional environments: [http://store.aapg.org/detail.aspx?id=627 AAPG Memoir 31], 410 p.</ref><ref name=pt05r141>Scholle, P. A., Bebout, D. G., Moore, C. H., 1983, Carbonate depositional environments: [http://store.aapg.org/detail.aspx?id=656 AAPG Memoir 33], 708 p.</ref>

Most fossil species required specific conditions of temperature, [[Wikipedia:Substrate (biology)|substrate]], and surrounding medium to carry on their normal activities. When conditions differed from ideal, the species is not present or is not preserved. The types of sedimentary rocks deposited under specific environmental conditions are ''biofacies'' and are identified by their specific rock properties including fossils.<ref name=pt05r140>Scholle, P. A., Spearing, D., 1982, Sandstone depositional environments: [http://store.aapg.org/detail.aspx?id=627 AAPG Memoir 31], 410 p.</ref><ref name=pt05r141>Scholle, P. A., Bebout, D. G., Moore, C. H., 1983, Carbonate depositional environments: [http://store.aapg.org/detail.aspx?id=656 AAPG Memoir 33], 708 p.</ref>

Fossils most commonly used in hydrocarbon exploration are microfossils (generally smaller than about 2 mm) because they can be recovered from drill cuttings without much damage to the fossils. Different processing techniques separate [[Calcareous microfossils|calcareous]], [[Siliceous microfossils|siliceous]], [[Phosphatic microfossils|phosphatic]], and [[Palynomorphs (organic-walled microfossils)|organic-walled fossils]].<ref name=pt05r100>Kummel, B., David, R., eds., 1965, Handbook of paleontological techniques: San Francisco, CA, W. H. Freeman, 852 p.</ref><ref name=pt05r55>Feldman, R. M., Chapman, R. E., Hannibal, J. T., eds., 1989, Paleotechniques: The Paleontological Society Special Publication No. 4, 358 p.</ref>

Fossils most commonly used in hydrocarbon exploration are microfossils (generally smaller than about 2 mm) because they can be recovered from drill cuttings without much damage to the fossils. Different processing techniques separate [[Calcareous microfossils|calcareous]], [[Siliceous microfossils|siliceous]], [[Phosphatic microfossils|phosphatic]], and [[Palynomorphs (organic-walled microfossils)|organic-walled fossils]].<ref name=pt05r100>Kummel, B., David, R., eds., 1965, Handbook of paleontological techniques: San Francisco, CA, W. H. Freeman, 852 p.</ref><ref name=pt05r55>Feldman, R. M., Chapman, R. E., Hannibal, J. T., eds., 1989, Paleotechniques: The Paleontological Society Special Publication No. 4, 358 p.</ref>

The major groups of marine fossils are [[nannoplankton]] (sometimes called [[coccoliths]]), [[foraminifera]], [[radiolaria]], [[diatoms]], [[conodonts]], [[ostracods]], [[palynomorphs]] (such as organic-walled [[dinoflagellates]]), [[spores]] and [[pollen]], and various types of [[megafossils]]. Nonmarine facies may yield spores and pollen, and [[lacustrine facies]] may also contain ostracods and [[diatoms]]. These and other fossils are described in the ''Encyclopedia of Paleontology''.<ref name=pt05r54>Fairbridge, R. W., Jablonski, D., eds., 1979, The Encyclopedia of Paleontology: Stroudsburg, PA, Dowden, Hutchinson and Ross, Inc., 886 p.</ref>

The major groups of marine fossils are [[Calcareous_microfossils#Calcareous_nannofossils|nannoplankton]] (sometimes called [[coccoliths]]), [[foraminifera]], [[Siliceous_microfossils#Radiolarians|radiolarians]], [[Siliceous_microfossils#Diatoms|diatoms]], [[Phosphatic_microfossils#Conodonts|conodonts]], [[Calcareous_microfossils#Ostracods|ostracods]], [[Palynomorphs_(organic-walled_microfossils)|palynomorphs]] (such as organic-walled [[Palynomorphs_(organic-walled_microfossils)#Dinoflagellates|dinoflagellates]]), [[Palynomorphs_(organic-walled_microfossils)#Spores_and_pollen|spores and pollen]], and various types of megafossils. Nonmarine facies may yield spores and pollen, and [http://www.merriam-webster.com/dictionary/lacustrinelacustrine] facies may also contain ostracods and [[diatoms]]. These and other fossils are described in the ''Encyclopedia of Paleontology''.<ref name=pt05r54>Fairbridge, R. W., Jablonski, D., eds., 1979, The Encyclopedia of Paleontology: Stroudsburg, PA, Dowden, Hutchinson and Ross, Inc., 886 p.</ref>

The distribution of fossils in a particular basin depends on the age of the strata, biogeographic setting, [[bathymetry]], [[depositional environment]], [[lithology]], and [[diagenetic events]]. Knowledge of these factors influences the decisions of whether to search for fossils in the drill cuttings or core and what fossil group to use.

The distribution of fossils in a particular basin depends on the age of the strata, [[Biogeography|biogeographic setting]], [[bathymetry]], [[depositional environment]], [http://www.thefreedictionary.com/lithology lithology], and [[Diagenesis|diagenetic events]]. Knowledge of these factors influences the decisions of whether to search for fossils in the drill cuttings or core and what fossil group to use.

===Geological age===

===Geological age===