| 词条 | Ranquil Formation |
| 释义 |
| name = Ranquil Formation | image = | caption = | type = Geological formation | period = Pliocene | age = Miocene–Pliocene | prilithology = Conglomerate with clay and silt matrix, breccia, sandstone, siltstone, mudstone | otherlithology = Conglomerate with sand matrix | namedfor = Caleta Ranquil | namedby = Juan Tavera | year_ts = 1942 | region = Bío Bío Region | country = {{CHL}} | coordinates = {{coord|37.6|S|73.7|W|display=inline,title}} | paleocoordinates = {{coord|37.9|S|71.4|W|display=inline}} | unitof = | subunits = | underlies = Tubul Formation | overlies = Lebu Group | thickness = | extent = | area = | map = {{Location map+ | Chile | relief = 1 | width = 150 | float = center | places = | lat_deg = -37.6 | lon_deg = -73.7 | mark = Yellow ffff00 pog.svg | marksize = 12 }} | map_caption = }}Ranquil Formation ({{lang-es|Formación Ranquil}}) is a Miocene and Pliocene sedimentary formation located in Arauco Province in south–central Chile, including outcrops in Mocha Island. The formation has its greatest thicknesses in the south-west, where its sediments were largely deposited in marine conditions. It overlies unconformably sedimentary formations of the Paleocene-Eocene Lebu Group.[1] The formation is part of the fill of Arauco Basin which is a sedimentary basin that extends south of Concepción.[2]Macrofossils of the formation are similar to those of Navidad (34° S) and Lacui Formations (43° S), two nearby Miocene marine formations.[2] The base of the Ranquil Formation is the so-called "main unconformity", which is thought to have been formed by erosion during a period of tectonic inversion.[3] The formation was first defined in 1942 by Juan Tavera.[1] UnitsThe formation has been subdivided into five units, with the lowermost being made up of sandstone and shale, and the second lowest one being made up of a conglomerate. The middle unit is made up of mudrock and massive sandstone. At some places the middle unit is overlain by a unit made up of sandstone with thin layers of conglomerate and sandstone that has been bioturbated. The uppermost unit include a breccia and the so-called Huenteguapi sandstone.[4] The sediments of Huenteguapi sandstone evidences that a megatsunami struck the coast of south–central Chile in the Pliocene.[4], which has been linked to the hypothetical Eltanin impact. Fossil contentRanquil Formation contains the following trace fossils: Zoophycos, Chondrites, Phycosiphon, Nereites missouriensis, Lockeiasiliquaria, Parataenidium, Ophiomorpha, Rhizocorallium and possibly also Psammichnites.[5] See also{{portal|Chile|Paleontology|Prehistory of South America|Neogene}}
References1. ^1 {{cite book |last=García A. |first=Floreal |date=1968 |title=El Terciario de Chile Zona Central |editor-last=Ceccioni |editor-first=Giovanni |url= |location=Santiago de Chile |publisher=Ediorial Andrés Bello |page=25–57 |isbn=|language=Spanish}} {{Geology of Chile}}2. ^{{cite journal |last=Finger |first=Kenneth L. |last2=Nielsen |first2=Sven N. |last3=Devries |first3=Thomas J. |last4=Encinas |first4=Alfonso |last5=Peterson |first5=Dwan E. |date=2007 |title=Paleontologic evidence for sedimentary displacement in Neogene forearc basins of Central Chile |url=http://www.ucmp.berkeley.edu/people/klf/KLF_files/Palaios.pdf |journal=Palaios |publisher= |volume=22 |issue= |pages=3–16 |doi= |access-date=28 July 2016}} 3. ^{{cite journal|last1=Becerra|first1=Juan|last2=Contreras-Reyes |first2=Eduardo |last3=Arriagada |first3=César |title=Seismic structure and tectonics of the southern Arauco Basin, south-central Chile (~ 38°S) |journal=Tectonophysics|date=2013|volume=592|pages=53-66}} 4. ^1 2 {{cite journal |last=Le Roux |first=J.P. |last2=Nielsen |first2= Sven N. |last3=Kemnitz |first3=Helga |last4=Henriquez |first4=Álvaro |date=2008 |title=A Pliocene mega-tsunami deposit and associated features in the Ranquil Formation, southern Chile |url=http://repositorio.uchile.cl/bitstream/handle/2250/125260/Le%20Roux_J_P.pdf?sequence=1 |journal=Sedimentary Geology |publisher= |volume=203 |issue=1 |pages=164–180 |doi= |access-date=11 April 2016}} 5. ^{{cite journal |last=Le Roux |first=Jacobus P. |last2=Nielsen |first2=Sven N. |last3=Henríquez |first3=Álvaro |date=2008 |title=Depositional environment of Stelloglyphus llicoensis isp. nov.: a new radial trace fossil from the Neogene Ranquil Formation, south-central Chile |url=http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082008000200006 |journal=Revista geológica de Chile |publisher= |volume=35 |issue=2 |pages=307–319 |doi= |access-date=29 July 2016}} 6 : Geologic formations of Chile|Miocene Series of South America|Pliocene Series of South America|Neogene Chile|Conglomerate formations|Geology of Bío Bío Region |
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