The Hasle Formation is a geologic formation on the island on Bornholm, Denmark. It is of early to late Pliensbachian 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. 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-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 Megaripples 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 represents a clear sea Transgression, due to the appearance of ammonites from Thuringia and southern Lower Saxony, 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 jamesoni in Kurremölla (Röddinge Formation, Skåne) and Beaniceras centaurus plus Phricodoceras 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 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 Genus Species Location Material Notes ImagesPentaditrupaP. quinquesulcataStampeå streamTwo tubesA sessile, marine annelid tube worm of the family SerpulidaeSerpula?S.? alicecooperiStampeå streamOne well-preserved tube and several fragmentary tubesA sessile, marine annelid tube worm of the family Serpulidae.
Brachiopoda Genus Species Location Material Notes ImagesRhynchonellaR. jurensis R. variabilisStampeå stream South of HasleShellsA saltwater Brachiopodan, member of Rhynchonellata inside Rhynchonellida. Found associated with Plicatula on long-term well-oxygenated conditions within the substrate and bottom waters.WaldheimiaW. sp.Stampeå streamShellsA saltwater lamp shell Brachiopodan, member of Terebratulidae inside Terebratulida. The specimens are rather incomplete. The genus is a possible junior synonym of Terebratula.
Bivalvia Genus Species Location Material Notes ImagesAstarteA. obsoleta A. sp. Stampeå stream South of HasleShellsA saltwater clam, type member of the family Astartidae inside Carditida. It is found on small, smooth clam associations, with the exception of one does section, with less well-preserved stone cores and imprints.AviculaA. inaequivalvis A. sp. Stampeå stream South of HasleShellsA saltwater pearl oyster, member of the family Pteriidae inside Ostreida. Some specimens are big and found associated with burrow-filled surfaces. This well-known species occurs extremely frequently; copies occur at all ages, as well as right-handers left shells have been found.CardiniaC. multicostatum C. crassiuscula C. infera Stampeå stream South of Hasle Hvideoddebuen NebbeoddeShellsA saltwater clam, type member of the family Cardiidae inside Carditida. Is a frequently occurring clam. CucullaeaC. sp. South of HasleShellsA saltwater clam, type member of the family Cucullaeidae inside Arcida. CyprinaC. cardioides Stampeå stream Hvideoddebuen NebbeoddeShellsA saltwater clam, member of the family Arcticidae inside Venerida. Is a frequently occurring clam.CypricardiaC. cf.laevigata C. cf.tetragona South of HasleShellsA saltwater clam, member of the family Trapezidae inside Venerida.DendostreaD. sandvichensis Stampeå streamShellsA saltwater oyster, member of the family Ostreinae inside Ostreida. Identified originally as Ostrea semiplicataGervilleiaG. sjögreni G. cf. hagenovii G. sp. Stampeå stream South of HasleShellsA saltwater oyster, member of the family Bakevelliidae inside Ostreida. Found on a series of incomplete stone cores filled with specimens, that by size and form can be possibly attributable to Gervilleia aerosa.HinnitesH. tumidus Stampeå streamShellsA saltwater scallop, member of the family Pectinidae inside Pectinida. A pair of incomplete specimens of a Hinnites are known and probably match with the species Hinnites tumidus; however, the state of preservation is bad, with the assignment rather uncertain.LimaL. succincta Stampeå streamShellsA saltwater file clam, type member of the family Limidae inside Pectinida. LimeaL. acuticosfa Stampeå streamShellsA saltwater file clam, member of the family Limidae inside Pectinida. Mostly know due to a single young individual.LuciniolaL. pumila Stampeå streamShellsA saltwater clam, type member of the family Lucinidae inside Lucinida. ModiolusM. scalprum M. sp. South of HasleShellsA saltwater mussel, type member of the family Mytilidae inside Mytilida.MyoconchaM. stampensis M. jespersenii Stampeå streamShellsA saltwater clam, member of the family Kalenteridae inside Cardiida. One of the most frequent and characteristic fossils in the formation MytilusM. sp. South of HasleShellsA saltwater mussel, type member of the family Mytilidae inside Mytilida.NuculaN. distinguenda N. (Leda?) dr. omaliusi? N. pinguis Stampeå streamShellsA saltwater nut clam, type member of the family Nuculidae inside Nuculida. Two copies of a Nucula (leda?) so closely in accordance with Moberg's depictions and description of occurring at Kurremolla. NuculanaN. bornholmiensis N. subovalis N. complanata Stampeå streamShellsA saltwater pointed nut clam, type member of the family Nuculanidae inside Nuculida. Nuculana bornholmiensis is a very common species only found locally. PalaeoneiloP. bornholmiensis P. sp. Stampeå stream South of HasleShellsA saltwater pointed nut clam, type member of the family Nuculanidae inside Nuculida. ParallelodonP. cypriniformis P. pullus Stampeå stream South of HasleShellsA saltwater clam, type member of the family Parallelodontidae inside Arcida. This species occurs frequently and varies a lotPectenP. priscus P. aequivalvis Stampeå stream South of Hasle Hvideoddebuen NebbeoddeShellsA saltwater scallop, type member of the family Pectinidae inside Pectinida. This species has been exceedingly frequent, and numerous fragments are available. PernaP. sp. South of HasleShellsA saltwater mussel, member of the family Mytilidae inside Mytilida.PleuromyaP. forchhammeri P. dunkeri Stampeå stream South of Hasle Hvideoddebuen NebbeoddeShellsA saltwater clam, type member of the family Pleuromyidae inside Pholadida. Three specimens of this genus have been found.PlicatulaP. spinosa Stampeå streamShellsA saltwater scallop, type member of the family Plicatulidae inside Pectinida. Two poorly preserved specimens have been found. SpondylusS. sp. South of HasleShellsA saltwater scallop, member of the family Pectinoidae inside Pectinida.TancrediaT. lineata T. elegans T. tenera T. johnstrupi Stampeå stream South of HasleShellsA saltwater clam, type member of the family Tancrediidae inside Carditida. Tancredia lineata Is based on six shell cores, of which one complete, the others a little defective at the front end. TellinaT. sp. South of HasleShellsA saltwater tellin clam, member of the family Tellinidae inside Cardiida.
Scaphopoda Genus Species Location Material Notes ImagesLaevidentaliumL. etalense L. elongatum L. sp. Stampeå stream South of HasleShellsA saltwater tusk shell (Scaphopoda), member of the family Dentaliidae inside Dentaliida
Gastropoda Genus Species Location Material Notes ImagesActaeoninaA. nathorstiStampeå stream South of HasleShellsA saltwater snail, type member of the family Acteoninidae inside Prosobranchia. Of this small species there are quite a few specimens, both stone cores and imprints that perfectly allow identifying the species.AmberlyaA. sp.South of HasleShellsA saltwater snail, type member of the family Spirostylidae inside Murchisoniina.ChemnitziaC.? undulata C. craticia C. citharella C. blainvilleiStampeå streamShellsA saltwater snail, member of the family Pyramidellidae inside Pyramidelloidea. Two specimens of a Turritella-like gastropod found locally have been refer to the genus. Chemnitzia citharella includes ten specimens, the largest of the genus found locally. However, most of the specimens are shell cores.EucyclusE. sp.Stampeå streamShellsA saltwater snail, type member of the family Eucyclidae inside Seguenzioidea. The material available is rather poor.MargaritesM. solariumStampeå streamShellsA saltwater snail, member of the family Turbinidae inside Turbinoidea. Occurs frequently, especially on marine ingression surfaces.NaticaN. sp.South of HasleShellsA saltwater moon snail, type member of the family Naticidae inside Naticoidea.NeritinaN. cf.liasinaSouth of HasleShellsA saltwater snail, type member of the family Neritidae inside Neritoidea.PleurotomariaP. expansa P. sp. Stampeå stream South of HasleShellsA saltwater snail, type member of the family Pleurotomariidae inside Pleurotomarioidea. TrochusT. laevis T. subsulcatus Stampeå streamShellsA saltwater top snail, type member of the family Trochidae inside Trochoidea. Rare compared with other species found locally.
Belemnites Genus Species Location Material Notes Images NannobelusN. acutus Stampeå stream South of HaslePhragmoconesA belemnite, incertae sedis member of the family Belemnitida. Frequently shows the embryonic chamber preserved as a bladder, slightly bent forward-towards the ventral side.SubhastitesS. paxillosus S. sp. Stampeå streamPhragmoconesA belemnite, member of the family Hastitidae inside Belemnitida.
Ammonites Genus Species Location Material Notes ImagesAcanthopleuroceras?A.? sp. indet.Rønne Lervarefabrik Stampeå stream South of Hasle Hvideoddebuen