The Diabasbrottet Quarry ( 58°21′32.2″N 12°30′08.6″E / 58.358944°N 12.502389°E / 58.358944; 12.502389 ), located on Mt. Hunneberg , Västergötland , Sweden , is the location of the Global Boundary Stratotype Section and Point (GSSP) which marks the lower boundary of the Floian stage of the Lower Ordovician .
5-582: The lower boundary of the Floian is defined as the first appearance of Tetragraptus approximatus , a graptolite species. The rock section belongs to the Tøyen Formation and is dominated by shale . It is unusually fossiliferous , including fossilized remains of graptolites, conodonts , and trilobites . It is highly compressed, and the Ordovician section is only 12 m thick. The Floian stage
10-405: Is a stub . You can help Misplaced Pages by expanding it . First appearance datum First 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),
15-751: Is named after Flo Parish , a village 5 km to the southeast of the Diabasbrottet quarry. It was selected over "The Ledge" in western Newfoundland in 2000 and ratified as the GSSP by the International Union of Geological Sciences in 2002. This article about a specific stratigraphic formation in Europe is a stub . You can help Misplaced Pages by expanding it . This article about a location in Västra Götaland County , Sweden
20-575: The last appearance of a species in the geologic record. FADs are frequently used to designate segments in the geologic time scale . A given FAD can be used to define a Global Boundary Stratotype Section and Point (GSSP). For example, the beginning of the Tremadocian Stage of the Ordovician Period is marked by the first appearance of the conodont Iapetognathus fluctivagus in the geologic record. This occurs in bed 23 of
25-543: The rock formation known as the Green Point section, located in western Newfoundland , as well as in geologically correlated strata in many parts of the world. However, diachronous FADs can be problematic for correlating chronostratigraphic units, particularly over longer distances. Use of other data, such as radiometric data , may be ultimately necessary in order to establish more reliable correlations of chronostratigraphic units. This paleontology article
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