Lacui Formation

{{Short description|Marine Miocene sedimentary formation in Chiloé Island}}

{{Infobox rockunit

| name = Lacui Formation

| image =

| caption =

| type = Geological formation

| period = Serravallian

| age = Serravallian
(Laventan)
~{{fossil range|13.8|11.8}}

| prilithology =

| otherlithology =

| namedfor = Lacuy Peninsula

| namedby = Valenzuela

| year_ts = 1982

| region = Chiloé Island (Los Lagos Region)

| country = Chile

| coordinates = {{coord|41|50|S|74|00|W|display=inline,title}}

| unitof =

| subunits =

| underlies =

| overlies = Ancud Volcanic Complex

| thickness =

| extent =

| area =

| map = {{Location map+ | Chile

| relief = 1

| width = 200

| float = center

| places =

{{Location map~ | Chile

| lat_deg = -41.9

| lon_deg = -74.0

| mark = Yellow pog.svg

| marksize = 12

}}

}}

| map_caption =

}}

Lacui Formation ({{langx|es|Formación Lacui}}) is a marine Miocene sedimentary formation located in Chiloé Island with minor outcrops near Carelmapu on the mainland.{{cite book |last1=Charrier |first1=R.|last2=Pinto |first2=L.|last3=Rodríguez |first3=M.P. |editor-last1=Moreno |editor-first1=Teresa|editor-last2=Gibbons |editor-first2=Wes |title=The Geology of Chile |publisher=Geological Society of London |date=2007 |pages=92–96 |chapter=Tectonostratigraphic evolution of the Andean Orogen in Chile }} Gastropod shells are the most common macrofossils of Lacui Formation.{{Citation

| last = Finger

| first = Kenneth L.

| title = Miocene foraminifera from the south-central coast of Chile

| journal = Micropaleontology

| volume = 59

| issue = 4–5

| year = 2013

| pages = 341–492

| doi = 10.47894/mpal.59.4.01

| bibcode = 2013MiPal..59..341F

| url = http://www.ucmp.berkeley.edu/people/klf/KLF_files/2013.Micropaleontology.pdf

}} According to Sernageomin (1998) the formation dates to the earliest Serravallian — that is the Middle Miocene.

South of Lacui Formation there are equivalent sedimentary rocks in the islands of Ipún, Lemo and Stoke.{{cite book |last1=Encinas|first1=Alfonso |last2=Folguera|first2=Andrés|last3=Bechis|first3=Florencia|last4=Finger|first4=Kenneth L.|last5=Zambrano|first5=Patricio|last6=Pérez|first6=Felipe|last7=Benarbé|first7=Pablo|last8=Tapia|first8=Francisca|last9=Riffo|first9=Ricardo|last10=Buatois|first10=Luis|last11=Orts|first11=Darío|last12=Nielsen|first12=Sven N. |last13=Valencia|first13=Victor V.|last14=Cituño|first14=José |last15=Oliveros|first15=Verónica |last16=De Girolamo Del Mauro|first16=Lizet|last17=Ramos|first17=Víctor A.|date=2018 |chapter=The Late Oligocene–Early Miocene Marine Transgression of Patagonia|title=The Evolution of the Chilean-Argentinean Andes|editor=Folguera, A. |editor2=Contreras Reyes, E. |editor3=Heredia, N. |editor4=Encinas, A. |editor5=Iannelli, S. B. |editor6=Oliveros, V. |editor7=M. Dávila, F. |editor8=Collo, G. |editor9=Giambiagi, L. |editor10=Maksymowicz, A. |editor11=Iglesia Llanos, M.P. |editor12=Turienzo, M. |editor13=Naipauer, M. |editor14=Orts, D. |editor15=Litvak, V. D. |editor16=Alvarez, O. |editor17=Arriagada, C. |publisher=Springer|pages=443–474 |isbn=978-3-319-67774-3 |author-link17=Víctor Alberto Ramos}}