Sularp Brook (),

Lund Municipality Lund Municipality ( sv, Lunds kommun) is a municipality in Scania County, southern Sweden. Its seat is the city of Lund. As most municipalities in Sweden, the territory of municipality consists of many former local government units, united i ...

Skåne Scania, also known by its native name of Skåne (, ), is the southernmost of the historical provinces (''landskap'') of Sweden. Located in the south tip of the geographical region of Götaland, the province is roughly conterminous with Skåne ...

, Sweden, is the location of the

Global Boundary Stratotype Section and Point A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted ...

(GSSP) which marks the boundary between the Middle and Late epochs of the

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ...

period on the

geologic time scale The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geoch ...

. The

first appearance In American comic books and other stories with a long history, first appearance refers to the first issue to feature a fictional character. These issues are often highly valued by collectors due to their rarity and iconic status. Reader interes ...

of the

graptolite Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian (Miaolingian, Wuliuan) through the L ...

''Nemagraptus gracilis'' defines the boundary. The rock section consists primarily of dark-gray

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especia ...

and mudstone, except for a

phosphorite Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxi ...

marker bed 1.4 m above the GSSP, and was probably deposited at a water depth exceeding 100 m. Drill cores have revealed almost identical stratigraphy across an area several km wide. Due to heating, possibly from an intrusive dike, the stratotype is unfit for dating by magnetic analysis, but this lack is compensated by the diversity of chemostratigraphic and biostratigraphic options.

References

* * Geology of Sweden Stratigraphy of Europe Ordovician Sweden Geography of Skåne County Scania {{paleo-site-stub