| 1. |
- Ghobadi Pour, M., et al.
(författare)
-
Early Ordovician (Tremadocian) faunas and biostratigraphy of the Gerd-Kuh section, eastern Alborz, Iran
- 2015
-
Ingår i: Stratigraphy. - 1547-139X .- 2331-656X. ; 12:2, s. 55-61
-
Tidskriftsartikel (refereegranskat)abstract
- The Tremadocian of the East Alborz Region is dominated by condensed fine clasticsediments. These beds have yielded low to medium diversity trilobite associations, which belong to theolenid, nileid and raphiophorid biofacies, characteristic of an outer shelf environment. Five successivetrilobite biozones can be recognised in the Tremadocian succession of Alborz. The lower TremadocianAsaphellus inflatus–Dactylocephalus and Psilocephalina lubrica zones are characterised by mediumdiversity trilobite associations with strong links to contemporaneous faunas of South China. Three upperzones are documented in the section at Gerd-Kuh, the successive Vachikaspis insueta and Kayseraspiszones represent a low diversity interval during a time of rapid changes in the sea level changes; themedium diversity fauna of the Asaphellus fecundus–Taihungshania miqueli zone shows strong links tothe faunas of Mediterranean segment of Gondwana. Brachiopods in Gerd-Kuh are represented by themonotaxic Tarfaya Association and the low diversity Paralenorthis–Xinanorthis Association. Therecurrent oligotaxic Protambonites Association invaded the area in the late Tremadocian during shortterm regressive episodes.
|
|
| 2. |
- Álvaro, J. Javier, et al.
(författare)
-
Global Cambrian trilobite palaeobiogeography assessed using parsimony analysis of endemicity
- 2013
-
Ingår i: Early Palaeozoic Biogeography and Palaeogeography. - 0435-4052. - 9781862393738 ; Memoir 38:38, s. 273-296
-
Bokkapitel (refereegranskat)abstract
- Palaeobiogeographical data on Cambrian trilobites obtained during the twentieth century are combined in this paper to evaluate palaeoceanographic links through c. 30 myr, once these arthropods biomineralized. Worldwide major tectonostratigraphic units are characterized at series intervals of Cambrian time and datasets of trilobite genera (629 for Cambrian Series 2, 965 for Cambrian Series 3, and 866 for the Furongian Series) are analysed using parsimony analysis of endemicity. Special attention is given to the biogeographical observations made in microcontinents and exotic terranes. The same is done for platform-basinal transects of well-known continental margins. The parsimony analysis of endemicity analysis resulted in distinct palaeogeographical area groupings among the tectonostratigraphic units. With these groupings, several palaeobiogeographical units are distinguished, which do not necessarily fit the previously proposed biogeographical realms and provinces. Their development and spatial distributions are broadly controlled by Cambrian palaeoclimates, palaeogeographical conditions (e.g. carbonate productivity and anoxic conditions) and ocean current circulation.
|
|
| 3. |
- Holmer, L. E., et al.
(författare)
-
Ordovician (Darriwilian–Sandbian) linguliform brachiopods from the southern Cuyania Terrane of west-central Argentina
- 2016
-
Ingår i: Australasian Palaeontological Memoirs. - 0810-8889. ; 49, s. 31-50
-
Tidskriftsartikel (refereegranskat)abstract
- The first Ordovician micromorphic linguliform brachiopods are described from the Province of Mendoza of west-central Argentina. The focus of the study is on carbonate successions exposed in the San Rafael Block, south of the famous Precordillera of San Juan, La Rioja and Mendoza representing the largest area of the so-called Cuyania Terrane. In the San Rafael region, the lingulate brachiopod faunas occur in two successive assemblages. The older assemblage was recovered from the uppermost part of the Ponon Trehue Formation (Lenodus variabilis Biozone; Darriwilian), and is dominated by Numericoma rowelli sp. nov. It has an affinity to contemporaneous faunas from the Antelope Valley Limestone (Whiterockian) at Meiklejohn Peak in central Nevada. The second, younger assemblage was recovered from the lower Lindero Formation (upper Darriwilian-basal Sandbian; Pygodus serra and P. anserinus Biozones) and is mainly dominated by the new genus Mendozotreta, with its type species M. devota (Krause & Rowell), and Conotreta cf. multisinuata Cooper, Rhysotreta corrugata Cooper, Scaphelasma septatum Cooper, Ephippelasma minutum Cooper and Biernatia minor Cooper. In addition, the fauna includes Elliptoglossa sylvanica Cooper, Rowellella margarita Krause & Rowell and Paterula cf. perfecta Cooper. This second lingulate microbrachiopod assemblage is closely comparable to the coeval microbrachiopod fauna from the Pratt Ferry Formation of Alabama.
|
|
| 4. |
- Popov, Leonid E., et al.
(författare)
-
Himalayan Cambrian brachiopods
- 2015
-
Ingår i: Papers in Palaeontology. - : Wiley. - 2056-2799 .- 2056-2802. ; 1:4, s. 345-399
-
Tidskriftsartikel (refereegranskat)abstract
- A synoptic analysis of previously published material and new finds reveals that Himalayan Cambrian brachiopods can be referred to 18 genera, of which 17 are considered herein. These contain 20 taxa assigned to species, of which five are new: Eohadrotreta haydeni, Aphelotreta khemangarensis, Hadrotreta timchristiorum, Prototreta? sumnaensis and Amictocracens? brocki. Well-preserved topotype material from the classic Parahio Valley section is described for three species that have not previously been illustrated photographically. A biostratigraphical scheme based on Cambrian brachiopod occurrence is integrated with that recently proposed for trilobites. Regional correlations based on shared taxa within and across Himalayan lithotectonic belts demonstrate that erosion of Cambrian rocks in the Kurgiakh orogeny in the Parahio Valley removed little of the Parahio Formation and that all of the fossil-bearing lithotectonic zones share similar late early Cambrian brachiopods, suggesting regional faunal continuity at the time. Palaeobiogeographical analysis of the Cambrian brachiopod faunas from the Himalaya shows that they occupied a marginal position of the Australasian segment of Gondwana.
|
|
