Tubul Formation

{{Short description|Sedimentary formation in Chile}}

{{Infobox rockunit

| name = Tubul Formation

| image =

| caption =

| type = Geological formation

| period = Pleistocene

| age = Early Pleistocene

| prilithology = Clay-rich sandstone and silt

| otherlithology =

| namedfor = Caleta Tubul

| namedby = Egidio Feruglio

| year_ts = 1949

| region = Bío Bío Region

| country = Chile

| coordinates = {{coord|37.8|S|73.3|W|display=inline,title}}

| paleocoordinates = {{coord|37.9|S|72.8|W|display=inline}}

| unitof =

| subunits =

| underlies = Quaternary sediments

| overlies = Ranquil Formation

| thickness = >{{convert|100|m|ft|abbr=on}}

| extent =

| area =

| map = {{Location map+ | Chile

| relief = 1

| width = 150

| float = center

| places =

{{Location map~ | Chile

| lat_deg = -37.8

| lon_deg = -73.3

| mark = Yellow ffff80 pog.svg

| marksize = 12

}}

}}

| map_caption =

}}

Tubul Formation ({{langx|es|Formación Tubul}}) is an Early Pleistocene (formerly described as Middle Pliocene in 1968 and Late Pliocene in 1976)[https://paleobiodb.org/classic/displayCollResults?collection_no=89241 Las Peñas (Tubul Fm)] at Fossilworks.org sedimentary formation located in Arauco Province in south–central Chile. Its sediments were deposited in marine conditions. It overlies unconformably the folded sedimentary formations of Ranquil (Miocene–Pliocene), Quiriquina (Late Cretaceous) and the Lebu Group (Paleocene-Eocene).{{cite book |last=García A. |first=Floreal |date=1968 |title=El Terciario de Chile Zona Central |editor-last=Ceccioni |editor-first=Giovanni |location=Santiago de Chile |publisher=Editorial Andrés Bello |pages=25–57 |language=es}}

Mollusc fossils found in the formation derives from soft-bed environments (contrary to rocky coasts). Evidence from the fossil mollusc fauna of the Tubul Formation seem to indicate that local water temperatures were lower in the Pliocene than today. Waters and mollusc faunas of Magallanes Region are modern-day equivalents of Tubul Formation.

The formation was first defined by Egidio Feruglio in 1949.{{cite conference |url=http://biblioteca.sernageomin.cl/opac/DataFiles/11769v1pp135_138.pdf |archive-url=https://web.archive.org/web/20160818030732/http://biblioteca.sernageomin.cl/opac/DataFiles/11769v1pp135_138.pdf |url-status=dead |archive-date=August 18, 2016 |title=Mollusks of the Tubul Formation (South-Central Chile): Implications for the Early Pleistocene climate of the Southeastern Pacific |last1=Valdovinos |first1=Claudio |last2=Nielsen |first2=Sven N. |date=2006 |book-title=XI Congreso Geológico Chileno |volume=II |pages=135–138 }}