Variegated Member, Zorritos Formation: Early/Lower Miocene, Peru

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Gastropoda - Cerithiidae
Cerithium grillanum Spieker 1922
Gastropoda - Tonnidae
Dolium (Malea) sp. (Valenciennes 1833)
original and current combination Malea
Gastropoda - Neogastropoda - Buccinidae
Solenosteira alternata
Nassa zorritensis
Gastropoda - Neogastropoda - Conidae
Subspecies: Conus molis bravoi
Gastropoda - Naticidae
Polinices subangulata
Bivalvia - Pectinida - Anomiidae
Anomia berryi Spieker 1922
synonym of Anomia peruviana
Bivalvia - Arcida - Arcidae
Arca (Noetia) cholana Spieker 1922
Arca (Scapharca) pantheonensis Spieker 1922
Arca (Cunearca) sp. (Dall 1898)
spelled with current rank as Anadara (Cunearca)
Arca (Anadara) nelsoni Spieker 1922
synonym of Anadara (Grandiarca) chiriquiensis
Arca (Anadara) septifera Grzybowski 1899
synonym of Anadara (Grandiarca) chiriquiensis
Arca (Anadara) toroensis Spieker 1922
synonym of Anadara (Grandiarca) chiriquiensis
Bivalvia - Pholadida - Corbulidae
Corbula (Cuneocorbula) propinqua
original and current combination Cuneocorbula
Corbula (Cuneocorbula) fabiformis
original and current combination Cuneocorbula
Bivalvia - Cardiida - Veneridae
Macrocallista helenae
Dosinia (Dosinidia) grandis Nelson 1870
synonym of Dosinia ponderosa
see common names

Geography
Country:Peru State/province:Tumbes
Coordinates: 3.7° South, 80.7° West (view map)
Paleocoordinates:4.9° South, 76.4° West
Basis of coordinate:based on nearby landmark
Geographic resolution:local area
Time
Period:Neogene Epoch:Miocene
10 m.y. bin:Cenozoic 5
Key time interval:Early/Lower Miocene
Age range of interval:23.03000 - 15.98000 m.y. ago
Stratigraphy
Formation:Zorritos Member:Variegated
Local section:Zorritos
Regional section:Tumbes-Progreso
Stratigraphic resolution:member
Stratigraphy comments: Stated as Early Miocene by Spieker (1922) and corroborated by more recent publications (e.g. see Higley 2004). Overlies the late Oligocene-early Miocene Heath Fm and underlies the Cardalitos Fm in Higley (2004) although Spieker (1922) uses varying lithostratigraphic nomenclature suggesting a "Talara Fm" overlies the upper member of the Zorritos Fm. Its is not clear whether definitions of these members has changed since Spieker. The variegated member of the Zorritos Fm is 310 ft thick and comprises claystone, oyster beds, and conglomeratic horizons.
Lithology and environment
Primary lithology:green,red poorly lithified claystone
Secondary lithology: unlithified argillaceous,sandy conglomerate
Includes fossils?Y
Includes fossils?Y
Lithology description: Comprises the following: 1) green clay, locally red, gray, publish; 2) carbonaceous shale, gypsiferous; 3) oyster bed; 4) heavy beds of pebbles, with sandy and argillaceous matrix interbedded with clays and loose friable sandstones; 5) green clay, locally red, gray, purplish.
Environment:coastal indet.
Geology comments: Shallow water, sandy littoral, agitated.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Preservation of anatomical detail:medium
Collection methods and comments
Collection methods:field collection,survey of museum collection
Reason for describing collection:taxonomic analysis
Museum repositories:YPM
Collection method comments: Collected by J. Singewald, and with inspection of collections by E.T. Nelson (1870) at Yale University. Possibly also involved inspection of Grzybowski's material (Geol. Inst. of Cracow). Singewald's material is presumably reposited at Johns Hopkins.
Taxonomic list comments:Probably not exhaustive though certainly representative of diversity of Mollusca for these units.
Metadata
Database number:59000
Authorizer:A. Hendy Enterer:A. Hendy
Research group:marine invertebrate
Created:2006-03-05 21:25:43 Last modified:2013-11-25 13:37:23
Access level:the public Released:2006-03-05 21:25:41
Creative Commons license:CC BY
Reference information

Primary reference:
16748. E. M. Spieker. 1922. The Paleontology of the Zorritos Formation of the North Peruvian Oil Fields. The Johns Hopkins University Studies in Geology 3:1-196 [A. Miller/A. Hendy]