In order to evaluate the relationship between thrust loading and sedimentary facies evolution, we analyse the progradation of £uvial coarse-grained deposits in the retroarc foreland basin system of the northern Andes of Colombia.We compare the observed sedimentary facies distribution with the calculated one-dimensional (1D) Eocene to Quaternary sediment-accumulation rates in the Medina wedge-top basin and with a three-dimensional (3D) sedimentary budget based on the interpretation of $1800 km of industry-style seismic re£ection pro¢les and borehole data. Age constraints are derived from a new chronostratigraphic framework based on extensive fossil palynological assemblages.The sedimentological data from the Medina Basin reveal rapid accumulation of £uvial and lacustrine sediments at rates of up to $500 m my À 1 during the Miocene. Provenance data based on gravel petrography and paleocurrents reveal that these Miocene £uvial systems were sourced from Upper Cretaceous and Paleocene sedimentary units exposed to the west in the Eastern Cordillera. Peak sediment-accumulation rates in the upper Carbonera Formation and the Guayabo Group occur during episodes of coarse-grained facies progradation in the early and late Miocene proximal foredeep.We interpret this positive correlation between sediment accumulation and gravel deposition as the direct consequence of thrust activity along the Servita¤^Lengupa¤ faults.This contrasts with one class of models relating gravel progradation in more distal portions of foreland basin systems to episodes of tectonic quiescence.

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Emphasis upon publication as a means of "diffusing knowledge" was expressed by the first Secretary of the Smithsonian. In his formal plan for the Institution, Joseph Henry outlined a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This theme of basic research has been adhered to through the years in thousands of titles issued in series publications under the Smithsonian imprint, commencing with Smithsonian Contributions to Knowledge in 1848 and continuing with the following active series: Smithsonian Contributions to Anthropology Smithsonian Contributions to Botany Smithsonian Contributions to History and Technology Smithsonian Contributions to the Marine Sciences Smithsonian Contributions to Museum Conservation Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology In these series, the Smithsonian Institution Scholarly Press (SISP) publishes small papers and full-scale monographs that report on research and collections of the Institution's museums and research centers. The Smithsonian Contributions Series are distributed via exchange mailing lists to libraries, universities, and similar institutions throughout the world. Manuscripts intended for publication in the Contributions Series undergo substantive peer review and evaluation by SISP's Editorial Board, as well as evaluation by SISP for compliance with manuscript preparation guidelines (available at https://scholarlypress.si.edu). For fully searchable PDFs of all open access series and publications of the Smithsonian Institution Scholarly Press, visit Open SI at http://opensi.si.edu.

During the Miocene, Andean tectonism caused the development of a vast wetland across western Amazonia. Palynological studies have been the main source of chronological and paleobotanical information for this region, including several boreholes in the Solimões Formation in western Brazilian Amazonia. Here, a palynological study of well core 1-AS-105-AM drilled in Tabatinga (Amazonas, Brazil) is presented: 91 new taxa are erected (25 spores and 66 pollen, including one new genus), 16 new combinations are proposed, and a list of botanical/ecological affinities is updated. We recorded 23,880 palynomorphs distributed in 401 different types. Among pollen and spores, 62 extant families and 99 extant genera were identified, which accounts for 39% and 30% of known botanical affinities to the family and genus level, respectively. Individual samples have pollen/spore counts with approximately 25% to 95% of known affinities to the family level. Pollen associations are sourced primarily from the wetland environments and to a minor extent from nonflooded forests. Palynological diversity analyses indicate an increase from the early to the middle/early late Miocene in core 1-AS-105-AM. Probable scenarios to explain this diversity increase include a higher degree of environmental complexity from the middle Miocene onwards, that is, a more heterogeneous riverscape, including broader extensions of nonflooded forests, as opposed to the swamp-dominated early Miocene. Additionally, the positive effects of the Miocene Climatic Optimum on plant richness could explain the increase in pollen richness. We posit hypotheses of forest diversification that can be tested as more botanical affinities are established along with a longer Miocene record.

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INTRODUCTION :We here present the surface models of two specimens of sloths(Mammalia, Tardigrada) coming from the Late Pliocene WareFormation (Cocinetas Basin, La Guajira, Colombia, see Table 1). Along with three additional sloth taxa found in the same Formation, these specimens document the great diversity of this Neotropical locality. Furthermore, they represent a sloth assemblage from a locality just a few hundred thousand years older than the classically recognized first main pulse of the Great American Biotic interchange, that is located few hundred kilometers away from the Isthmus of Panama, the most likely route of migration of terrestrial taxa. These specimens are hence important in the understanding of this majorpaleobiogeographic event. AbstractThe present 3D Dataset contains the 3D models analyzed in Neogene sloth assemblages (Mammalia, Pilosa) of the Cocinetas Basin (La Guajira, Colombia): implications for the Great American Biotic Interchange. Palaeontology.

Freshwater fossil fish faunas have been long used to infer past drainage connections, as they are bounded by physical freshwater barriers. Here we study a middle Miocene (15.0-15.5 Ma) fossil fauna (Makaraipao) from the Castilletes Formation in northern Colombia, nowadays west of the Andes. We record the presence of lungfishes (Lepidosiren), pacus (Mylossoma and Piaractus), armored catfishes (Callichthyidae), and red-tail catfishes (Phractocephalus). Extant members of all those groups (except the Callichthyidae, due to lack of taxonomic resolution) are found in Amazonian faunas east of the Andes and are absent from faunas west of the Andes, indicating that the riverine systems of the Guajira Peninsula were connected to Amazonia during the middle Miocene. The similarity of La Venta (west of the Andes) and Rio Acre (east of the Andes) fish faunas during the late Miocene further indicates that the northern Andean uplift was not a complete barrier at least until ~ 11 Myr ago. However, there is a continental-wide structuring of the Miocene fish faunas that is also found in the extant faunas, suggesting that other factors, in addition to the uplift of the Andes, have shaped the biogeographic evolution of South American fish faunas.