Tazareh Section, Alburz Mts, Deltaic facies 2: Late/Upper Aalenian, Iran
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Bivalvia
- Pectinida
- Entoliidae
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Entolium sp.
(Meek 1865)
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Bivalvia
- Pholadomyida
- Pholadomyidae
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Pholadomya sp.
Sowerby 1823
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unclassified
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Rhizocorallium irregulare
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| see common names | |||||||
Geography
| Country: | Iran |
| Coordinates: | 36.4° North, 54.5° East (view map) |
| Paleocoordinates: | 13.8° South, 47.7° East |
| Basis of coordinate: | stated in text |
| Geographic resolution: | outcrop |
Time
| Period: | Jurassic | Epoch: | Middle Jurassic |
| Stage: | Aalenian | 10 m.y. bin: | Jurassic 3 |
| Key time interval: | Late/Upper Aalenian | ||
| Age range of interval: | 174.70000 - 170.90000 m.y. ago |
Stratigraphy
| Formation: | Shemshak |
| Stratigraphic resolution: | group of beds |
Lithology and environment
| Primary lithology: | bioturbation,fine,coarse lithified silty sandstone |
| Secondary lithology: | planar lamination,fine lithified sandstone |
| Lithology description: A widespread facies association are bioturbated silty fine-grained sandstones, rich in comminuted plant debris, with intercalations of 2–20 cm thick, fine-grained sandstones. The latter exhibit a sharp, planar base, are graded, parallel-laminated, and occasionally topped by oscillation ripples. Rarely, their internal structure is made up of hummocky cross-stratification, followed by wave ripple lamination. Wood fragments are common. | |
| Environment: | deltaic indet. |
| Geology comments: The sharp-based, parallel-laminated, graded sandstones intercalated between highly bioturbated fine-sandy silt and the rare hummock cross-stratified sandstone beds have been deposited by density currents. In contrast to the tempestites discussed below, which exhibit more or less identical features, they are interpreted as sediments of the lower delta front and prodelta, because up-section they grade into upper delta front sandstones and distributary channel deposits....There is no clear and distinct boundary between prodelta sediments and outer shelf sediments. | |
Taphonomy
| Modes of preservation: | body |
| Size of fossils: | macrofossils |
Collection methods and comments
| Collection methods: | field collection |
| Reason for describing collection: | biostratigraphic analysis |
Metadata
| Database number: | 141260 | ||
| Authorizer: | M. Aberhan | Enterer: | T. Schossleitner | Research group: | marine invertebrate |
| Created: | 2013-03-23 03:49:15 | Last modified: | 2013-03-22 11:49:15 |
| Access level: | the public | Released: | 2013-03-23 03:49:15 |
| Creative Commons license: | CC BY |
Reference information
Primary reference:
| 45909. | F. T. Fürsich, M. Wilemsen, K. Seyed-Emami, F. Cecca, and M. R. Majidifard. 2005. The upper Shemshak Formation (Toarcian–Aalenian) of the Eastern Alborz (Iran): Biota and palaeoenvironments during a transgressive–regressive cycle. Fazies 51:365-384 [M. Aberhan/T. Schossleitner/T. Schossleitner] |