Allgäu Formation

{{Short description|Geologic formation in Austria}}

{{Infobox rockunit

| name = Allgäu Formation

| image =

| caption =

| type = Formation

| age = Hettangian-Sinemurian (Raricostatum-Obtusum)
~{{fossil range|201|191}}

| period = Sinemurian

| prilithology = Marl

| otherlithology = Limestone

| namedfor =

| namedby =

| region = Vorarlberg
Bavaria
Graubünden

| country = Austria
Germany
Switzerland

| coordinates = {{coord|47.7|N|13.7|E|display=inline,title}}

| paleocoordinates = {{coord|32.5|N|19.9|E|display=inline}}

| unitof =

| subunits = Alpisella beds

| underlies =

| overlies =

| thickness =

| extent =

| area =

| map = {{Location map+ | Austria

| relief = 1

| width = 250

| float = center

| places =

{{Location map~ | Austria

| lat_deg = 47.7

| lon_deg = 13.7

| mark = Blue pog.svg

| marksize = 10

}}

{{Location map~ | Austria

| lat_deg = 46.6

| lon_deg = 10.1

| mark = Blue pog.svg

| marksize = 10

}}

{{Location map~ | Austria

| lat_deg = 47.8

| lon_deg = 12.6

| mark = Blue pog.svg

| marksize = 10

}}

}}

| map_caption =

}}

The Allgäu Formation is a geologic formation in Austria, Germany and Slovakia. It preserves fossils dating back to the Hettangian to Sinemurian stages of the Early Jurassic period, or Raricostatum to Obtusum in the regional stratigraphy. Initially and formally defined by Jacobshagen (1965).Jacobshagen, 1965 The Allgäu Formation is formerly known as spotted marls (Lias-Fleckenmergel) and spotted marly limestones (Fleckenkalk). The formation is represented by dark-grey bioturbated limestones and marlstone interbeds. It represents basinal hemipelagic faciesGawlick et al., 2009 common in Alpine Tethys regions of Alps, Carpathians and other mountain ranges. Several horizons of the formation are particularly rich in ammonite fauna.