PBDB Collection

Paraguachon Vertebrates (Miocene of Colombia)

Where: La Guajira, Colombia (11.9° N, 71.4° W: paleocoordinates 11.0° N, 67.7° W)

• coordinate stated in text

When: Jimol Formation, Early/Lower Miocene (23.0 - 16.0 Ma)

• The invertebrate fauna of the Jimol Formation shares high similarity with the Cantaure Formation (latest early Miocene) of Venezuela (Jung, 1965) and the Culebra Formation (early Miocene) of Panama (Woodring, 1957). Most notable among molluscs are frequent specimens of Orthaulax, a taxon that is widespread in the Caribbean during the early Miocene and earliest middle Miocene (Vokes & Vokes, 1968). Other marine invertebrate taxa identified from the formation are regarded as indicative of the latest early Miocene (e.g., “Paraleptopecten” quirosensis, Cyclinella venezuelana, and Conus cf. chipolanus) or middle Miocene (e.g., Modulus tamenensis), or are similar to middle-late Miocene forms (e.g., Lindapecten cf. buchivacoanus). On the basis of 87Sr/86Sr ratios, a mean age of 17.3 Ma (range of 16.89 ± 0.12 Ma-17.51 ± 0.11 m.y.) is calculated for beds northwest of the village of Paraguachón at the top of the formation. A late early Miocene (Burdigalian, 17.9 to 16.7 Ma) age is therefore assigned to the Jimol Formation on the basis of macroinvertebrate biostratigraphy and 87Sr/86Sr isotope chronostratigraphy.

Environment/lithology: marine; lithified, calcareous sandstone and lithified, yellow wackestone

• The Jimol Formation was deposited in a shallow marine environment, inner shelf depth (<50 m).

• The Jimol Formation is composed of grey calcareous lithic sandstone and lithic sandstone, yellowish grey fossiliferous wackstone to packstone, and grey to brown siltstones and mudstone. At the base, 50 cm to 1 m thick beds of coarse calcareous lithic sandstone and lithic sandstone, with ripples, cross and planar bedding, and fossiliferous wackestone to packstone dominate the sequence. There are occasional ~5 m thick beds of siltstone and mudstone in this part of the sequence. At the top mudstone and fine-grained calcareous lithic sandstone and lithic sandstone in 5 m to 20 m thick beds dominate the sequence interbedded with 50 cm to 2 m thick beds of fine- to medium-grained calcareous sandstone, and fossiliferous wackestone to packstone.

Size class: macrofossils

Primary reference: J. F. Moreno, A. J. W. Hendy, L. Quiroz, N. Hoyos, D. S. Jones, V. Zapata, S. Zapata, G. A. Ballen, E. Cadena, A. L. Cardenas, J. D. Carrillo, J. D. Carrillo, D. Delgado-Sierra, J. Escobar, J. I. Martinez, C. Martinez, C. Montes, J. Moreno, N. Perez, R. Sanchez, C. Suarez and M. C. Valle. 2015. Revised stratigraphy of Neogene strata in the Cocinetas Basin, La Guajira, Colombia. Swiss Journal of Paleontology [C. Jaramillo/A. Cardenas /M. Vallejo]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 166507: authorized by Carlos Jaramillo, entered by Andrés Cárdenas on 16.02.2015

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names

Reptilia
Crocodylia - Crocodylidae	Crocodylidae sp. Crocodylidae sp. crocodile
Crocodylia - Gavialidae	Gavialidae sp. Gavialidae sp. crocodilian
Chondrichthyes
Myliobatiformes - Myliobatidae	Myliobatidae sp. Myliobatidae sp. Bonaparte 1838 eagle ray
Carcharhiniformes - Carcharhinidae	Carcharhinidae sp. Carcharhinidae sp. Jordan and Evermann 1896 requiem shark
Carcharhiniformes - Hemigaleidae	Hemigaleidae sp. Hemigaleidae sp. ground shark
Lamniformes - Lamnidae	Lamnidae sp. Lamnidae sp. Müller and Henle 1838 mackerel shark
Squaliformes - Dalatiidae	Dalatiidae sp. Dalatiidae sp. Gray 1851 shark