Chronostratigraphic units are bounded by synchronous horizons. The rank and relative magnitude of the units in the chronostratigraphic hierarchy are a function of the length of the time interval that their rocks subtend, rather than of their physical thickness. Chronostratigraphic horizon Chronohorizon. A stratigraphic surface or interface that is synchronous, everywhere of the same age. Kinds of Chronostratigraphic Units. Hierarchy of formal chronostratigraphic and geochronologic unit terms.
The Guide recommends the following formal chronostratigraphic terms and geochronologic equivalents to express units of different rank or time scope Table 3. Position within a chronostratigraphic unit is expressed by adjectives indicative of position such as:basal, lower, middle, upper, etc. Stage and Age. The stage has been called the basic working unit of chronostratigraphy because it is suited in scope and rank to the practical needs and purposes of intraregional chronostratigraphic classification. The stage includes all rocks formed during an age.
A stage is normally the lowest ranking unit in the chronostratigraphic hierarchy that can be recognized on a global scale. It is a subdivision of a series. Boundaries and stratotypes. A stage is defined by its boundary stratotypes, sections that contain a designated point in a stratigraphic sequence of essentially continuous deposition, preferably marine, chosen for its correlation potential. The selection of the boundaries of the stages of the Standard Global Chronostratigraphic Scale deserves particular emphasis because such boundaries serve to define not only the stages but also chronostratigraphic units of higher rank, such as series and systems.
Time span. The lower and upper boundary stratotypes of a stage represent specific moments in geologic time, and the time interval between them is the time span of the stage. Currently recognized stages vary in time span, but most range between 2 and 10 million years.
Isotope chronostratigraphy : theory and methods - Semantic Scholar
The thickness of the strata in a stage and its duration in time are independent variables of widely varying magnitudes. The name of a stage should be derived from a geographic feature in the vicinity of its stratotype or type area. In English, the adjectival form of the geographic term is used with an ending in "ian" or "an". The age takes the same name as the corresponding stage. Substage and Superstage.
A substage is a subdivision of a stage whose equivalent geochronologic term is subage. Adjacent stages may be grouped into a superstage.
- Perishables Buyer December 2011.
- Post Office Jobs: The Ultimate 473 Postal Exam Study Guide and Job Finder.
- Isotopes, Natural - Miller - - Major Reference Works - Wiley Online Library;
Names of substages and superstages follow the same rules as those of stages. Series and Epoch. The series is a chronostratigraphic unit ranking above a stage and below a system. The geochronologic equivalent of a series is an epoch. The terms superseries and subseries have been used only infrequently. Boundaries and boundary-stratotypes. Series are defined by boundary stratotypes see section 9. See section 9. The time span of currently accepted series ranges from 13 to 35 million years.
A new series name should be derived from a geographic feature in the vicinity of its stratotype or type area. The names of most currently recognized series, however, are derived from their position within a system:lower, middle, upper. Names of geographic origin should preferably be given the ending "ian" or "an". The epoch corresponding to a series takes the same name as the series except that the terms "lower" and "upper" applied to a series are changed to "early" and "late" when referring to an epoch. Misuse of"series". The use of the term "series" for a lithostratigraphic unit more or less equivalent to a group should be discontinued.
System and Period. A system is a unit of major rank in the conventional chronostratigraphic hierarchy, above a series and below an erathem. The geochronologic equivalent of a system is a period. Occasionally, the terms subsystem and supersystem have been used. The boundaries of a system are defined by boundary-stratotypes see section 9. The time span of the currently accepted Phanerozoic systems ranges from 30 to 80 million years, except for the Quaternary System that has a time span of only about 1.
The names of currently recognized systems are of diverse origin inherited from early classifications: some indicate chronologic position Tertiary, Quaternary , others have lithologic connotation Carboniferous, Cretaceous , others are tribal Ordovician, Silurian , and still others are geographic Devonian, Permian.
- Guidelines for project evaluation.
- Navigation menu.
Likewise, they bear a variety of endings such as "an", "ic", and "ous". There is no need to standardize the derivation or orthography of the well-established system names. The period takes the same name as the system to which it corresponds. Erathem and Era. An erathem consists of a group of systems. The geochronologic equivalent of an erathem is an era. The names of erathems were chosen to reflect major changes of the development of life on the Earth:. Paleozoic old life , Mesozoic intermediate life , and Cenozoic recent life. Eras carry the same name as their corresponding erathems.
Eonothem and Eon. An eonothem is a chronostratigraphic unit greater than an erathem. The geochronologic equivalent is an eon. Three eonothems are generally recognized, from older to younger, the Archean, Proterozoic and Phanerozoic eonothems. The combined first two are usually referred to as the Precambrian.
Isotopes: principles and applications. Isotope chronostratigraphy : theory and methods. Geochronology, time scales, and global stratigraphic correlation Magnetic stratigraphy Quantitative stratigraphy. Isotopes and climates. Paleoclimatology : reconstructing climates of the quaternary Principles of paleoclimatology Climates: past, present.
Isotope chronostratigraphy : theory and methods
Isotope geology. Radiogenic isotope geology Stable isotope geochemistry Geohistory :global evolution of the earth. Please login. Science , , "Archived copy". Archived from the original on CS1 maint: archived copy as title link.
Isotope Chronostratigraphy: Theory and Methods
Past history deep time Present Future Futures studies Far future in religion Far future in science fiction and popular culture Timeline of the far future Eternity Eternity of the world. Horology History of timekeeping devices Main types astrarium atomic quantum hourglass marine sundial sundial markup schema watch mechanical stopwatch water-based Cuckoo clock Digital clock Grandfather clock. Chronology History. Religion Mythology.
Geological time age chron eon epoch era period Geochronology Geological history of Earth. Chronological dating Chronobiology Circadian rhythms Dating methodologies in archaeology Time geography. Periods Eras Epochs. Canon of Kings Lists of kings Limmu. Chinese Japanese Korean Vietnamese. Lunisolar Solar Lunar Astronomical year numbering. Deep time Geological history of Earth Geological time units. Chronostratigraphy Geochronology Isotope geochemistry Law of superposition Luminescence dating Samarium—neodymium dating. Amino acid racemisation Archaeomagnetic dating Dendrochronology Ice core Incremental dating Lichenometry Paleomagnetism Radiometric dating Radiocarbon Uranium—lead Potassium—argon Tephrochronology Luminescence dating Thermoluminescence dating.