The Hasle Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

on the island on

Bornholm Bornholm () is a Danish island in the Baltic Sea, to the east of the rest of Denmark, south of Sweden, northeast of Germany and north of Poland. Strategically located, Bornholm has been fought over for centuries. It has usually been ruled by ...

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , establishe ...

. It is of early to late

Pliensbachian The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 190.8 ± 1.5 Ma and 182.7 ± 1.5 Ma (million years ago). The ...

age. Vertebrate fossils have been uncovered from this formation. The type section of the formation is found at the south of the costal Hasle Town, and it is composed by rusty yellow to brownish siltstones and very fine-grained sandstones. The southernmost arch, Hvjdoddebuen, is not as fossil-bearing as the type unit in Hasle. The formation can be separated in two different petrographic types: type 1 sandstones are friable with layers and lenses of concretionary siderite and type 2 well-cemented sandstones. Both types where deposited in a relatively high-energy marine environment with a diagenetic pattern that demonstrates a close relation to various phases of subsidence and uplift in the tectonically unstable

Fennoscandian Border Zone __NOTOC__ Fennoscandia ( Finnish, Swedish and no, Fennoskandia, nocat=1; russian: Фенноскандия, Fennoskandiya) or the Fennoscandian Peninsula is the geographical peninsula in Europe, which includes the Scandinavian and Kola penins ...

. Most of its deposition happened on a storm-dominated shoreface, with the exposed parts deposited in an open marine shelf within 1–2 km distance from the fault-controlled coastlines. However, recent works have recovered terrestrial fauna from it, including a footprint, suggesting easterly winds and low tide could have exposed the inner parts of the upper shoreface, and create long-lasting

Floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

-type environments. Field works since 1984 have shown a mostly hummocky cross-stratified deposition, with great complexity of the sediments that suggests very complicated and variable flow conditions, with

Megaripple In geology, ripple marks are sedimentary structures (i.e., bedforms of the lower flow regime) and indicate agitation by water (current or waves) or wind. Defining ripple cross-laminae and asymmetric ripples * ''Current ripple marks'', ''unid ...

s derived from storm events. Storms were frequent and the coastline faced a wide epeiric sea with a fetch towards the west of possibly 1000 kilometers. The Jamesoni–Ibex Chronozone in the

Central European Basin Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known a ...

represents a clear sea Transgression, due to the appearance of ammonites from

Thuringia Thuringia (; german: Thüringen ), officially the Free State of Thuringia ( ), is a state of central Germany, covering , the sixth smallest of the sixteen German states. It has a population of about 2.1 million. Erfurt is the capital and lar ...

and southern

Lower Saxony Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state (') in northwestern Germany. It is the second-largest state by land area, with , and fourth-largest in population (8 million in 2021) among the 16 ...

, showing a full marine ingression towards the west. This rise in the sea level is also measured in the north, as is proven by the presence of ''

Uptonia ''Uptonia'' is an extinct ammonite from the Lower Jurassic that's included in the eoderoceratoidean family Polymorphitidae. The shell of ''Uptonia'' is evolute with rounded simple ribs that form strong chevrons as they cross the venter on the o ...

jamesoni'' in Kurremölla (

Röddinge Formation The Röddinge Formation is a geologic formation in Skåne County, southern Sweden. It is Early Jurassic (Sinemurian-Toarcian) in age. It is a unit with a limited degree of exposure, being identified mostly by its deposits on the Fyledalen Fault Zo ...

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 ...

) and ''

Beaniceras ''Aegoceras'' (''Beaniceras'') is small, coarsely ribbed subgenus ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are m ...

centaurus'' plus ''

Phricodoceras ''Phricodoceras'' is an extinct genus of cephalopod belonging to the Ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, ar ...

taylori'' on the Hasle Formation. The whole Hasle Sandstones are a result of this rise in the sea level, where the marine sediments cover the deltaic layers of the

Rønne Formation The Rønne Formation is a geologic formation on the island on Bornholm, Denmark. It is of middle Hettangian to early Pliensbachian age. Vertebrate fossils have been uncovered from this formation. During the Early Jurassic, on what is now the Bo ...

. The rise in the sea level is observed on palynology, as on the Hasle Formation '' Nannoceratopsis senex'' (Dinoflajellate) and '' Mendicodinium reticulaturn'' (Algae Acritarch) appear, indicating a transition from paralic and restricted marine to fully marine.

Fossil content

Annelida

Brachiopoda

Bivalvia

Scaphopoda

Gastropoda

Belemnites

Ammonites

Chondrichthyes

Unidentified fin spines are known from this formation.

Actinopteri

Sauropterygia

Thalattosuchia

Pterosauria

Theropods

Sauropodomorpha

Synapsida

References

{{reflist Geologic formations of Denmark Jurassic System of Europe Jurassic Denmark Sandstone formations Shallow marine deposits Paleontology in Denmark Formations