Los Alamitos vertebrates, middle section, collection point M Q F S: Late/Upper Campanian - Early/Lower Maastrichtian, Argentina
collected by J. F. Bonaparte, J. E. Powell 1982
Where & when
Geology
Taphonomy & methods
Metadata & references
Geography
| Country: | Argentina | State/province: | Río Negro |
| Coordinates: | 42.1° South, 66.3° West (view map) | ||
| Paleocoordinates: | 45.0° South, 52.3° West | ||
| Basis of coordinate: | estimated from map | ||
| Geographic resolution: | outcrop |
Time
| Period: | Cretaceous | Epoch: | Late/Upper Cretaceous |
| Key time interval: | Late/Upper Campanian - Early/Lower Maastrichtian | ||
| Age range of interval: | 83.60000 - 66.00000 m.y. ago |
Stratigraphy
| Formation: | Los Alamitos | ||||
| Local section: | Los Alamitos Stratotype | Local bed: | 32 m | ||
| Local order: | bottom to top | ||||
| Stratigraphic resolution: | group of beds | ||||
| Stratigraphy comments: middle section of formation includes vertebrate fossils distributed over about 11 meters of section | |||||
Lithology and environment
| Primary lithology: | fine,red siltstone |
| Includes fossils? | Y |
| Lithology description: "Pelitic facies: includes dominant massive, laminated or rippled (rare) siltstones and claystones, with yellowish (lower part of the sequences) to reddish, orange, brown and purple hues (upper part), and massive sandstones. This rocks show typical paquidermis solution pattern which allow its recognition in outcrops. The non-calcareous pelites contains (lower half) almost all the vertebrate remains" | |
| Environment: | lacustrine - large |
| Geology comments: dominant environment lacustrine, more brackish than fresh (clay flocculation in pelites). waters were oxygenated; lake permanent and shallow.
The paleoenvironment according to Andreis (1987; and personnal communication) is that of a lacustrine environment mixed with shallow marine sediments, as indicated by the presnce of glauconite in some levels of the sequence. | |
Taphonomy
| Modes of preservation: | body |
| Degree of concentration: | dispersed |
| Size of fossils: | macrofossils,mesofossils |
| Preservation of anatomical detail: | good |
| Articulated whole bodies: | none |
| Associated major elements: | some |
| Disassociated major elements: | many |
| Disassociated minor elements: | many |
| Fragmentation: | frequent |
| Temporal resolution: | time-averaged |
| Spatial resolution: | parautochthonous |
Collection methods and comments
| Collection excludes: | some macrofossils | ||
| Collection methods: | selective quarrying,surface (float),surface (in situ),mechanical,field collection | ||
| Reason for describing collection: | general faunal/floral analysis | ||
| Collectors: | J. F. Bonaparte, J. E. Powell | Collection dates: | 1982 |
| Taxonomic list comments:In this collection point there are fragments of mammals, turtles, snakes and fishes, already included in the general collection point 45087. We will try to sort out which of the specimens are included herein, if possible. | |||
Metadata
| Also known as: | Los Alamitos vertebrates, middle section, Cerro Cuadrado, Arroyo Verde, collection points A-I-H-G-B-F-C-D-E | ||
| Database number: | 231690 | ||
| Authorizer: | E. Vlachos | Enterer: | E. Vlachos | Research group: | vertebrate |
| Subset of collection #: | 45087 | ||
| Created: | 2023-08-28 13:45:37 | Last modified: | 2023-08-28 13:45:37 |
| Access level: | the public | Released: | 2023-08-28 13:45:37 |
| Creative Commons license: | CC BY | ||
Reference information
Primary reference:
| 11733. | ETE | R. R. Andreis. 1987. The Late Cretaceous fauna of Los Alamitos, Patagonia, Argentina part I—stratigraphy and paleontology. Revista del Museo Argentina de Ciencias Naturales "Bernardino Rivadavia" e Instituto Nacional de Investigacion de las Ciencias Naturales: Paleontología 3(3):103-110 [M. Carrano/M. Carrano/M. Carrano] |