Whiterock StageThe Whiterockian, often referred to simply as the Whiterock, is an earliest or lowermost stage of the Middle Ordovician. Although the Whiterockian or Whiterock Stage refers mainly to the early Middle Ordovician in North America, it is often used in the older literature in a global sense.
DapingianSubdivision of the Ordovician according to the ICS, as of 2024.Vertical axis scale: Millions of years agoEtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the ConodontBaltoniodus triangularisLower boundary GSSPHuanghuachang section, Huanghuachang, Yichang, China30°51′38″N110°22′26″E / 30.8605°N 110.3740°E / 30.8605; 110.3740Lower GSSP ratified2007Upper boundary definitionFAD of the GraptoliteUpper boundary GSSPHuangnitang Section, Huangnitang Village, Changshan, Zhejiang, China28°51′14″N118°29′23″E / 28.8539°N 118.4897°E / 28.8539; 118.4897Upper GSSP ratified1997The Dapingian is the third stage of the Ordovician system and the first stage of the Middle Ordovician series.
First appearance datumFirst appearance datum (FAD) is a term used by geologists and paleontologists to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest fossil discovered, to date, of a particular species. A related term is last appearance datum (LAD), the last appearance of a species in the geologic record. FADs are frequently used to designate segments in the geologic time scale.
ConodontConodonts are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (kōnos), meaning "cone", and ὀδούς (odoús), meaning "tooth"). They are primarily known from their hard, mineralised tooth-like structures called "conodont elements" that in life were present in the oral cavity and used to process food. Rare soft tissue remains suggest that they had elongate eel-like bodies with large eyes.
Early OrdovicianThe Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 486.85 to 471.3 million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages.
Conodont biostratigraphyConodonts are an extinct class of animals whose feeding apparatuses called teeth or elements are common microfossils found in strata dating from the Stage 10 of the Furongian, the fourth and final series of the Cambrian, to the Rhaetian stage of the Late Triassic. These elements can be used alternatively to or in correlation with other types of fossils (graptolites, trilobites, ammonites, ...) in the subfield of the stratigraphy named biostratigraphy.Cambrian Stage 10Stage 10 of the Cambrian is the still-unnamed third and final stage of the Furongian series. It follows the Jiangshanian and precedes the Ordovician Tremadocian Stage. The proposed lower boundary is the first appearance of the trilobite Lotagnostus americanus around 491 million years ago, but other fossils are also being discussed (see below).SandbianThe Sandbian is the first stage of the Upper Ordovician. It follows the Darriwilian and is succeeded by the Katian. Its lower boundary is defined as the first appearance datum of the graptolite species Nemagraptus gracilis around 458.2 million years ago. The Sandbian lasted for about 5.4 million years until the beginning of the Katian around 452.8 million years ago.
OrdovicianSecond period of the Paleozoic EraSubdivision of the Ordovician according to the ICS, as of 2024.Vertical axis scale: Millions of years agoEtymologyName formalityFormalName ratified1960Usage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitPeriodStratigraphic unitSystemFirst proposed byCharles Lapworth, 1879Time span formalityFormalLower boundary definitionFAD of the ConodontIapetognathus fluctivagusLower boundary GSSPGreenpoint section, Green Point, Newfoundland, Canada49°40′58″N57°57′55″W / 49.6829°N 57.9653°W / 49.6829; -57.9653Lower GSSP ratifiedJanuary 2000Upper boundary definitionFAD of the GraptoliteAkidograptus ascensusUpper boundary GSSPDob's Linn, Moffat, U.K.55°26′24″N3°16′12″W / 55.4400°N 3.2700°W / 55.4400; -3.2700Upper GSSP ratified1984Atmospheric and climatic dataSea level above present day180 m; rising to 220 m in Caradoc and falling sharply to 141 m in end-Ordovician glaciationsThe Ordovician ( ) is a geologic period and system, the second of six periods of the PaleozoicEra, and the second of twelve periods of the PhanerozoicEon.
DarriwilianSubdivision of the Ordovician according to the ICS, as of 2024.Vertical axis scale: Millions of years agoEtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the GraptoliteLower boundary GSSPHuangnitang Section, Huangnitang Village, Changshan, Zhejiang, China28°51′14″N118°29′23″E / 28.8539°N 118.4897°E / 28.8539; 118.4897Lower GSSP ratified1997Upper boundary definitionFAD of the Graptolite Upper boundary GSSPFågelsång section, Sularp Brook, Skåne, Sweden55°42′49″N13°19′32″E / 55.7137°N 13.3255°E / 55.7137; 13.3255Upper GSSP ratified2002The Darriwilian is the upper stage of the Middle Ordovician.ProtoprioniodusProtoprioniodus is an extinct genus of conodonts.
TremadocianSubdivision of the Ordovician according to the ICS, as of 2024.Vertical axis scale: Millions of years agoEtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the ConodontIapetognathus fluctivagus.Lower boundary GSSPGreenpoint section, Green Point, Newfoundland, Canada49°40′58″N57°57′55″W / 49.6829°N 57.9653°W / 49.6829; -57.9653Lower GSSP ratified2000Upper boundary definitionFAD of the GraptoliteTetragraptus approximatusUpper boundary GSSPDiabasbrottet quarry, Västergötland, Sweden58°21′32″N12°30′09″E / 58.3589°N 12.5024°E / 58.3589; 12.5024Upper GSSP ratified2002The Tremadocian is the lowest stage of Ordovician.
DapingianSubdivision of the Ordovician according to the ICS, as of 2024.Vertical axis scale: Millions of years agoEtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the ConodontBaltoniodus triangularisLower boundary GSSPHuanghuachang section, Huanghuachang, Yichang, China30°51′38″N110°22′26″E / 30.8605°N 110.3740°E / 30.8605; 110.3740Lower GSSP ratified2007Upper boundary definitionFAD of the GraptoliteUpper boundary GSSPHuangnitang Section, Huangnitang Village, Changshan, Zhejiang, China28°51′14″N118°29′23″E / 28.8539°N 118.4897°E / 28.8539; 118.4897Upper GSSP ratified1997The Dapingian is the third stage of the Ordovician system and the first stage of the Middle Ordovician series.First appearance datumFirst appearance datum (FAD) is a term used by geologists and paleontologists to designate the first appearance of a species in the geologic record. FADs are determined by identifying the geologically oldest fossil discovered, to date, of a particular species. A related term is last appearance datum (LAD), the last appearance of a species in the geologic record. FADs are frequently used to designate segments in the geologic time scale.ConodontConodonts are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (kōnos), meaning "cone", and ὀδούς (odoús), meaning "tooth"). They are primarily known from their hard, mineralised tooth-like structures called "conodont elements" that in life were present in the oral cavity and used to process food. Rare soft tissue remains suggest that they had elongate eel-like bodies with large eyes.Early OrdovicianThe Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 486.85 to 471.3 million years ago, until the Dapingian age of the Middle Ordovician. It includes Tremadocian and Floian ages.Conodont biostratigraphyConodonts are an extinct class of animals whose feeding apparatuses called teeth or elements are common microfossils found in strata dating from the Stage 10 of the Furongian, the fourth and final series of the Cambrian, to the Rhaetian stage of the Late Triassic. These elements can be used alternatively to or in correlation with other types of fossils (graptolites, trilobites, ammonites, ...) in the subfield of the stratigraphy named biostratigraphy.Cambrian Stage 10Stage 10 of the Cambrian is the still-unnamed third and final stage of the Furongian series. It follows the Jiangshanian and precedes the Ordovician Tremadocian Stage. The proposed lower boundary is the first appearance of the trilobite Lotagnostus americanus around 491 million years ago, but other fossils are also being discussed (see below).SandbianThe Sandbian is the first stage of the Upper Ordovician. It follows the Darriwilian and is succeeded by the Katian. Its lower boundary is defined as the first appearance datum of the graptolite species Nemagraptus gracilis around 458.2 million years ago. The Sandbian lasted for about 5.4 million years until the beginning of the Katian around 452.8 million years ago.OrdovicianSecond period of the Paleozoic EraSubdivision of the Ordovician according to the ICS, as of 2024.Vertical axis scale: Millions of years agoEtymologyName formalityFormalName ratified1960Usage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitPeriodStratigraphic unitSystemFirst proposed byCharles Lapworth, 1879Time span formalityFormalLower boundary definitionFAD of the ConodontIapetognathus fluctivagusLower boundary GSSPGreenpoint section, Green Point, Newfoundland, Canada49°40′58″N57°57′55″W / 49.6829°N 57.9653°W / 49.6829; -57.9653Lower GSSP ratifiedJanuary 2000Upper boundary definitionFAD of the GraptoliteAkidograptus ascensusUpper boundary GSSPDob's Linn, Moffat, U.K.55°26′24″N3°16′12″W / 55.4400°N 3.2700°W / 55.4400; -3.2700Upper GSSP ratified1984Atmospheric and climatic dataSea level above present day180 m; rising to 220 m in Caradoc and falling sharply to 141 m in end-Ordovician glaciationsThe Ordovician ( ) is a geologic period and system, the second of six periods of the PaleozoicEra, and the second of twelve periods of the PhanerozoicEon.DarriwilianSubdivision of the Ordovician according to the ICS, as of 2024.Vertical axis scale: Millions of years agoEtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the GraptoliteLower boundary GSSPHuangnitang Section, Huangnitang Village, Changshan, Zhejiang, China28°51′14″N118°29′23″E / 28.8539°N 118.4897°E / 28.8539; 118.4897Lower GSSP ratified1997Upper boundary definitionFAD of the Graptolite Upper boundary GSSPFågelsång section, Sularp Brook, Skåne, Sweden55°42′49″N13°19′32″E / 55.7137°N 13.3255°E / 55.7137; 13.3255Upper GSSP ratified2002The Darriwilian is the upper stage of the Middle Ordovician.ProtoprioniodusProtoprioniodus is an extinct genus of conodonts.TremadocianSubdivision of the Ordovician according to the ICS, as of 2024.Vertical axis scale: Millions of years agoEtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the ConodontIapetognathus fluctivagus.Lower boundary GSSPGreenpoint section, Green Point, Newfoundland, Canada49°40′58″N57°57′55″W / 49.6829°N 57.9653°W / 49.6829; -57.9653Lower GSSP ratified2000Upper boundary definitionFAD of the GraptoliteTetragraptus approximatusUpper boundary GSSPDiabasbrottet quarry, Västergötland, Sweden58°21′32″N12°30′09″E / 58.3589°N 12.5024°E / 58.3589; 12.5024Upper GSSP ratified2002The Tremadocian is the lowest stage of Ordovician.*As an Amazon Associate I earn from qualifying purchases.