Page 350 - Geology and Geochemistry of Oil and Gas

GLOSSARY 311
consequence of the trend from a less probable to a
more probable state.
Eogenetic All diagenetic processes operative from the time of
sediment formation, including marine and meteoric
processes, until the sediments or rocks ultimately are
buried and away from the influence of surface and
near-surface processes.
Eolian Referring to processes and products of sediment
transport, erosion, or deposition by wind.
Epeiric sea A shallow sea on a broad continental shelf or an
inland sea covering large portions of continent; in the
latter case, commonly considered to be tideless.
Partial syn: Epicontinental sea.
Epibionts In reference to encrusting organisms or that
population of organisms that has encrusted various
substrate.
Epigenesis Late diagenetic processes that have occurred, and
resulting products that have formed, in the deep
burial environments. Cf: Eogenetic.
Erosion The physical and/or chemical processes whereby the
earthy and rocky materials of the Earth’s crust are
loosened, dissolved, or worn away, and
simultaneously removed from one place to another by
running water (including rainfall), waves and
currents, moving ice, or wind.
Error The difference between an observed, calculated, or
measured value of a quantity, and the ideal or true
value of that quantity. The following types of errors
are distinguished: accidental, constant, instrumental,
mean-square, personal, probable, random, residual,
sampling, standard, statistical, systematic, and also
Type I and Type II errors in a hypothesis-testing
procedure.
Ethane A colorless, odorless, gaseous paraffin hydrocarbon,
formula C 2 H 6 , which occurs in natural gas.
Eustatic Rise or fall in sea level due to global changes in
the volume of the ocean. Cf: Relative sea level
change.
Euxinic An environment of restricted circulation, with
stagnant or anaerobic conditions.
Evaporite One of the sediments which are deposited from
aqueous solution as a result of extensive or total
evaporation. Examples include anhydrite, rock salt,
and various nitrates and borates.