Xert Formation

{{Short description|Geologic formation in Spain}}

{{Infobox rockunit

| name = Xert Formation

| image =

| caption =

| type = Geological formation

| age = Late Barremian
~{{fossil range|122|120}}

| period = Barremian

| prilithology = Limestone, marl

| otherlithology = Claystone, chert

| namedfor = Chert

| namedby =

| region = Aragón

| country = Spain

| coordinates = {{coord|40.7|N|0.1|E|display=inline,title}}

| paleocoordinates = {{coord|30.1|N|10.2|E|display=inline}}

| unitof =

| subunits =

| underlies = Forcall Formation

| overlies = Artoles Formation, Arcillas de Morella Formation

| thickness =

| extent = Maestrazgo Basin
 Galve Basin

| area =

| map = {{Location map+ | Spain#Spain Aragon

| relief = 1

| width = 250

| float = center

| places =

{{Location map~ | Spain#Spain Aragon

| lat_deg = 40.7

| lon_deg = 0.1

| mark = Green pog.svg

| marksize = 10

}}

}}

| map_caption =

}}

The Calizas y margas de Xert Formation or Xert Formation is an Early Cretaceous (late Barremian) geologic formation of the Maestrazgo and Galve Basins in central-eastern Spain. The formation is described as a coastal claystone, with indications of a transgressive episode, marked by the transition from marsh facies, with little marine influence, to marine platform facies evidenced by abundant marine invertebrates.[https://paleobiodb.org/classic/displayCollResults?collection_no=58204 Xert Formation] at Fossilworks.org