Sample# 2, Lagoinhas, Santa Maria (subunit B1): Late/Upper Pleistocene, Portugal
collected by Ávila et al 2003
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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unclassified
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Auriculinella bidentata
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1 specimen | ||||||
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Gastropoda
- Planaxidae
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Fossarus ambiguus
(Linnaeus 1758)
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8 specimens | ||||||
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Gastropoda
- Cerithiidae
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Bittium latreillii
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788 specimens | ||||||
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Gastropoda
- Triphoridae
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Triphoridae indet.
Gray 1847
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43 specimens | ||||||
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Gastropoda
- Cerithiopsidae
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Cerithiopsis sp.
Hanley 1849
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7 specimens | ||||||
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Gastropoda
- Triviidae
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Trivia sp.
Broderip 1837
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2 specimens | ||||||
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Gastropoda
- Neogastropoda
- Muricidae
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Ocinebrina aciculata
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14 specimens | ||||||
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Gastropoda
- Neogastropoda
- Nassariidae
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Nassarius incrassatus
(Müller 1773)
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1 specimen | ||||||
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Gastropoda
- Neogastropoda
- Columbellidae
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Anachis avaroides
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39 specimens | ||||||
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Gastropoda
- Neogastropoda
- Horaiclavidae
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Haedropleura septangularis
(Montagu 1803)
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5 specimens | ||||||
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Gastropoda
- Neogastropoda
- Mitromorphidae
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Mitromorpha azorensis
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8 specimens | ||||||
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Gastropoda
- Naticidae
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Natica cf. prietoi
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2 specimens | ||||||
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Polynices lacteus
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1 specimen | ||||||
| original and current combination Polinices | |||||||
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Gastropoda
- Rissoidae
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Manzonia unifasciata
Dautzenburg 1889
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28 specimens | ||||||
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Cingula trifasciata
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67 specimens | ||||||
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Alvania abstersa
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13 specimens | ||||||
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Alvania formicarum
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1 specimen | ||||||
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Alvania mediolittoralis
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419 specimens | ||||||
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Alvania poucheti
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39 specimens | ||||||
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Alvania sleursi
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131 specimens | ||||||
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Alvania cancellata
(da Costa 1778)
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2 specimens | ||||||
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Rissoa guernei
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220 specimens | ||||||
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Gastropoda
- Littorinidae
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Melarhaphe neritoides
(Linnaeus 1758)
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69 specimens | ||||||
| recombined as Littorina neritoides | |||||||
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Gastropoda
- Trochidae
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Calliostoma sp.
Swainson 1840
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11 specimens | ||||||
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Jujubinus pseudogravinae
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11 specimens | ||||||
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Gastropoda
- Patellidae
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Patella sp.
Linnaeus 1758
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3 specimens | ||||||
| see common names | |||||||
Geography
| Country: | Portugal |
| Coordinates: | 37.0° North, 25.1° West (view map) |
| Paleocoordinates: | 37.0° North, 25.1° West |
| Basis of coordinate: | based on nearby landmark |
| Geographic resolution: | outcrop |
Time
| Period: | Quaternary | Epoch: | Pleistocene |
| Stage: | Late/Upper Pleistocene | 10 m.y. bin: | Cenozoic 6 |
| Key time interval: | Late/Upper Pleistocene | ||
| Age range of interval: | 0.12900 - 0.01170 m.y. ago |
Stratigraphy
| Local section: | Lagoinhas | Local bed: | B1 | ||
| Local order: | bottom to top | ||||
| Stratigraphic resolution: | bed | ||||
| Stratigraphy comments: STRATIGRAPHIC RELATIONS: From unnamed Late Quaternary marine deposits. AGE: early Late Pleistocene. Dated on the basis of U series. recently, Ávila et al. (2008a) dated the basal conglomerate of the Prainha outcrop (subunit A1 of Ávila et al., 2002) as Marine Isotopic Substage 5.5 (MIS 5.5), based on U/Th ages on shells of Patella spp. As explained by Ávila et al. (2008a), due to taphonomic problems and the wet climatic conditions prevailing on the island, the U-series measurements from their fossilized remains can only help constrain the age of the uranium taken up diagenetically. U-series data from Santa Maria Island indicate. an open system, providing mean 230Th ages that are much younger than the true age of the unit. They suggest relatively steady, more or less continuous, diagenetic U-uptake by the fossils since their deposition in the Pleistocene. Thus, accepting an age of 130–120 ka for the deposits, Ávila et al. (2008a) estimated that within the embedded biogenic carbonates U-uptake rates varied from c. 2.5 to 5 μg g CaCO−31 kyr−1. This was based on 230Th-ages in the 60–70 ka range, for shells that would have started accumulating diagenetic U some 130–120 ka ago (i.e. during the MIS 5.5) (Ávila et al., 2008a). STRATIGRAPHIC POSITION: Succession comprises cemented and bored carbonate sands, overlaind by 0.5 m beach sands with concentrations of shell debris. | |||||
Lithology and environment
| Primary lithology: | shelly/skeletal,yellow unlithified sandstone |
| Includes fossils? | Y |
| Lithology description: SPECIFIC LITHOLOGY: Yellow uncemented lithic sands (dominated by the 250–500 μm [Lagoinhas] fraction), apart from the volcanogenic grains consisting almost exclusively of small mollusc fragments (carbonate contents ranging from 56.2 to 67.3% in the samples investigated). LITHIFICATION: Unlithified, as described in text. | |
| Environment: | foreshore |
| Geology comments: ENVIRONMENT: Sediments correspond to beach foreshore (intertidal) facies and show marked similarities to the recent beach sands both in grain size and composition. | |
Taphonomy
| Modes of preservation: | body,original aragonite |
| Degree of concentration: | concentrated |
| Size of fossils: | macrofossils |
| Fragmentation: | frequent |
| Feeding/predation traces: | drill holes |
| Temporal resolution: | time-averaged |
| Spatial resolution: | allochthonous |
Collection methods and comments
| Collection excludes: | some macrofossils | ||
| Collection methods: | bulk,sieve,field collection | ||
| Minimum sieve size: | 0.250 | ||
| Reason for describing collection: | paleoecologic analysis | ||
| Collectors: | Ávila et al | Collection dates: | 2003 |
| Collection method comments: COLLECTOR: S. Ávila and others, Febuary 17, 2003. REPOSITORY: Not stated in text, but presumably the Universidade dos Açores. METHODS: Ten bulk samples of approximately 1 kg each were collected from the sand facies of the Lagoinhas deposit in a standardised sample spacing (about 50 cm laterally between contiguous samples). Sampling was restricted to fresh material, obtained from in-situ deposits after removal of weathered residues. Samples were disaggregated by short ultrasonic treatment and gentle wet-sieving. A mesh width of 0.250 mm was chosen, allowing the retrieval of almost all determinable remains of the macrobenthos (including fragments). Molluscs were the most abundant group recovered, accompanied by rare brachiopods and echinoderm debris. | |||
| Taxonomic list comments:COVERAGE: Exhaustive faunal list for gastropods. Bivalves omitted from sample faunal lists. NOMENCLATURE: Not an authoritative publication, but with modern nomenclature and species-resolution identifications. | |||
Metadata
| Database number: | 122284 | ||
| Authorizer: | A. Hendy | Enterer: | A. Hendy |
| Modifier: | A. Hendy | Research group: | marine invertebrate |
| Created: | 2011-12-20 23:47:08 | Last modified: | 2013-11-25 13:37:23 |
| Access level: | authorizer only | Released: | 2013-12-20 23:47:08 |
| Creative Commons license: | CC BY |
Reference information
Primary reference:
| 30051. | fossil record | S. P. Ávila, P. Madeira, C. Zazo, A. Kroh, M. Kirby, C. Marques Silva, M. Cachao and A. M. Frias Martins. 2009. Palaeoecology of the Pleistocene (MIS 5) outcrops of Santa Maria Island (Azores) in a complex oceanic tectonic setting. Palaeogeography, Palaeoclimatology, Palaeoecology 274:18-31 [W. Kiessling/U. Merkel/S. Ávila] |