Talacasto Formation | |
---|---|
Stratigraphic range: Devonian | |
Type | Geological formation |
Unit of | Gualilán Group |
Thickness | 300–1,000 m (980–3,280 ft) |
Location | |
Region | |
Country | Argentina |
Extent | Precordillera Basin |
Type section | |
Named by | Padula et al |
Year defined | 1967 |
The Talacasto Formation is a geological formation in Argentina, exposed primarily across San Juan Province, with an additional outcrop in La Rioja Province. It preserves fossils dating back to the Devonian period.
The Talacasto Formation is exposed in the Precordillera Basin of Argentina, with outcrops most widespread in San Juan Province, though an isolated exposure also exists at Sierra de las Minitas in La Rioja Province. [1] [2] Along with the Punta Negra Formation, it makes up the Gualilán Group, which represent Devonian-aged deposits in the Argentine Precordillera. [3] The thickness of the Talacasto Formation varies across its extent; at the type locality of Quebrada de Talacasto in the south it is 300 m (980 ft) thick, while at the Loma de los Piojos section near the Jáchal River in the north it exceeds 1,000 m (3,300 ft) in thickness. [1]
Color key
| Notes Uncertain or tentative taxa are in small text; |
Bivalves reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Actinopteria [4] | A. eschwegei | Loma de los Piojos | About 20 specimens | A pterineid | |
A. modesta | Loma de los Piojos | Several specimens | A pterineid | ||
Anthracoleda [4] | A. (Pseudoleda) minuta |
| Several specimens | A nuculanid | |
Deceptrix [4] | D. (Devonodeceptrix) jachalensis | Loma de los Piojos | Several specimens | A cardiolariid | |
Glossites [4] | G. cf. G. depressus | Loma de los Piojos | 2 specimens | A modiomorphid | |
Grammysioidea [4] | G. capricornus | Loma de los Piojos | 5 specimens | A grammysiid | |
Nuculites [4] | N. argentinum |
| Numerous specimens | A cucullellid | |
Nuculoidea [4] | N.? sp. | Cerro del Fuerte | 4 specimens | A nuculid | |
Palaeoneilo [4] | P. cf. P. forbesi | Loma de los Piojos | 5 internal moulds | A malletiid | |
Pholadella [4] | P. radiata | Loma de los Piojos | 7 specimens | A sanguinolitid | |
Brachiopods reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Anoplia [5] [6] | A. azucenae | Portezuelo del Tambolar | Over 70 specimens | An anopliid | |
A. sp. A | Río Talacasto | 6 specimens | An anopliid | ||
A. sp. | Los Algarrobos section | An anopliid | |||
Athyris [6] | A. sp. | Los Algarrobos section | An athyridid | ||
Australostrophia [5] | A. penoensis |
| Numerous specimens | A strophochonetid | |
Boucotia [7] | B. argentina |
| 3 isolated valves | A notanopliid | |
Chonostrophia [5] [8] | C. elenae | Loma de los Piojos | Several specimens | A chonostrophiid | |
C. reversa var. andina | Quebrada de Talacasto | Several specimens | Tentatively reclassified as a species of Sanjuanetes [9] | ||
Eoschucertella [10] | E. delicata | Quebrada Zerina | Numerous specimens | An areostrophiid | |
Iridistrophia [10] | I. aliciae | Cerro del Fuerte | Numerous specimens | A chilidiopsid | |
I. dominans | Loma de los Piojos | Numerous specimens | A chilidiopsid | ||
I. magna | Cordón de Agua de Peñón | Numerous specimens | A chilidiopsid | ||
I. prima | Quebrada La Cortadera | Numerous specimens | A chilidiopsid | ||
Kentronetes [5] | K. giolittii | Quebrada Las Loras | 6 valves | A strophochonetid | |
K. ortegae | Loma de los Piojos | Numerous specimens | A strophochonetid | ||
K. vallensis | Loma de los Piojos | 31 specimens | A strophochonetid | ||
K. variabilis |
| 32 valves | A strophochonetid | ||
Lingula [6] | L. sp. | Los Algarrobos section | A lingulid | ||
Lomaella [5] | L. primoris | Loma de los Piojos | 9 specimens | An eodevonariid | |
L. sanjuanina | Loma de los Piojos | Several specimens | An eodevonariid | ||
Meristella [6] | M. sp. | Los Algarrobos section | A meristellid | ||
Metaplasia [6] | M. baldisi | Los Algarrobos section | An ambocoeliid | ||
Pleurochonetes [5] | ?P. sp. | Loma de los Piojos | 32 specimens | A chonetid | |
Plicanoplia [5] | P. sp. | Loma de los Piojos | 5 specimens | An anopliid | |
Sanjuanetes [5] [6] [8] | ?S. andina |
| Several specimens | A strophochonetid, originally reported as Chonostrophia reversa var. andina [9] | |
Cephalopods reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Bactrites [1] | B. gracilis |
| 18 specimens | A bactritid | |
B. sp. |
| 5 specimens | A bactritid | ||
Devonobactrites [1] | D.? sp. | Loma de los Piojos section | 2 specimens | A bactritid | |
Corals reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Enterolasma [6] | E. sp. | Cerro del Fuerte section | Fragments & complete specimens | A horn coral | |
Favosites [6] | F.? sp. | Cerro del Fuerte section | 1 colony | A tabulate coral | |
Parastriatopora [6] [11] | P. cf. gigantea | Tambolar section | 6 small branch fragments | A tabulate coral | |
P. sanjuanina | Los Algarrobos section | A tabulate coral | |||
P. sp. | Los Algarrobos section | A tabulate coral | |||
Echinoderms reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Argentinaster [12] | A. bodenbenderi | Jachal | Several specimens | An ophiurinid brittle star | |
Crinoidea indet. [6] | Indeterminate | Los Algarrobos section | A crinoid | ||
Furcaster [12] | F. separatus | Jachal | Multiple specimens | A protasterid brittle star | |
Marginix [12] | M. yachalensis | Jachal | Several specimens | An encrinasterid brittle star | |
Promopalaeaster [12] | P.? quadriserialis | Jachal | Several specimens | A valvatid starfish | |
Hyoliths reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Hyolithida indet. [6] | Indeterminate | Los Algarrobos section | A hyolithid | ||
Ostracods reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Aechmina [13] | A. sp. | Talacasto Creek | 6 specimens | A member of Podocopa | |
Amphizona [13] | A.? argentinensis |
| 23 specimens | A member of Podocopa | |
Bollia [13] | B. talacastensis |
| 20 specimens | A member of Podocopa | |
Keslingiella [13] | K. teresae |
| Several specimens | A member of Podocopida | |
Lapazites [13] | L. aff. L. trinodis |
| 12 specimens | A member of Podocopa | |
Petrisigmoopsis [13] | P.? rotundum |
| Several specimens | A member of Podocopa | |
Pircawayra [13] [14] | P. antiqua |
| 5 specimens | A member of Palaeocopida | |
P. peregrina | Loma de los Piojos | Several specimens | A member of Palaeocopida | ||
Suinella [13] | S. huarpesi |
| Several specimens | A member of Podocopa | |
Thlipsurella [13] | T. aff. T. putea |
| 33 specimens | A member of Podocopida | |
Ulrichia [13] | U. sp. |
| 7 specimens | A member of Podocopa | |
Sponges reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Talacastospongia [15] | T. minima |
| 13 specimens | A glass sponge | |
Trilobites reported from the Talacasto Formation | |||||
---|---|---|---|---|---|
Genus | Species | Presence | Material | Notes | Images |
Aguaditaspis [16] | A. mediaspina |
| Several specimens | A dalmanitid | |
Bainella [17] | B. cooperi | Cerro La Chilca | 6 specimens | A calmoniid | |
B. sanjuanina | Cerro La Chilca | 8 specimens | A calmoniid | ||
Calmonia [17] | C. nov. sp. A | Loma de los Piojos | An internal mould (CORD PZ 8613) | A calmoniid | |
Dalmanitoides [18] | D. boehmi | Loma de los Piojos | Several specimens | A dalmanitid | |
D. drevermanni |
| Several specimens | A dalmanitid | ||
Dalmanitidae indet. [6] [16] | Gen. et. sp. nov. | Quebrada de las Aguaditas | One specimen (CEGH-UNC 27422) | An unnamed dalmanitid | |
Indeterminate | Los Algarrobos section | A dalmanitid | |||
Dalmanitinae gen. et. sp. indet. [2] | Indeterminate | Sierra de las Minitas | Fragmentary pygidium (PULR-132 A-B) | A dalmanitid | |
Deltacephalaspis [17] | D. sp. | Cerro La Chilca | 2 specimens | A calmoniid | |
Echidnops [2] [19] | E. taphomimus |
| 12 specimens | A phacopid, originally reported as an unnamed species of Paciphacops | |
Ivanites [16] | I. leonorae |
| Several specimens | A dalmanitid | |
Maurotarion [6] [20] [21] | M. (Malvinotarion) gaucho | Loma de los Piojos | 10 specimens | An aulacopleurid | |
M. (Malvinotarion) haudei | Loma de los Piojos | 2 specimens | An aulacopleurid | ||
M. (Malvinotarion) talacastoense | La Cantera point | 5 specimens | An aulacopleurid | ||
M. (Malvinotarion) sp. | Portezuelo del Tambolar | One specimen (CEGH-UNC 7.086) | An aulacopleurid | ||
M. (Malvinotarion) sp. B | Cerro La Chilca | One specimen | An aulacopleurid | ||
M. megacephalum | Loma de los Piojos | 23 specimens | An aulacopleurid | ||
M. sp. | Los Algarrobos section | An aulacopleurid | |||
Paciphacops [2] [6] | P. (Paciphacops) sp. | Sierra de las Minitas | Several specimens | Now known as Echidnops taphomimus [19] | |
P. sp. | Los Algarrobos section | A phacopid | |||
P.? sp. | Sierra de las Minitas | One specimen (PULR-127 A-B) | A phacopid | ||
Parabouleia [6] [22] | P. eldredgei | Quebrada de Talacasto | 9 specimens | A calmoniid | |
P. sp. | Los Algarrobos section | A calmoniid | |||
Talacastops [2] [22] | T. zarelae |
| Multiple specimens | A calmoniid | |
Tarijactinoides [17] | T. jarcasensis |
| 13 specimens | A calmoniid | |
Tormesiscus [2] | T. cf. hildae | Sierra de las Minitas | Partial specimen (PULR-130) | A calmoniid | |
Unguliproetus [2] | U.? sp. | Sierra de las Minitas | Two associated fragments | A proetid | |
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