INSUGEO   12554
INSTITUTO SUPERIOR DE CORRELACION GEOLOGICA
Unidad Ejecutora - UE
artículos
Título:
Trilobites de la Formación Volcancito (Miembro Filo Azul, Cámbrico Tardío) del Sistema de Famatina, La Rioja, Argentina: aspectos sistemáticos y paleoambientales
Autor/es:
TORTELLO, MARCELO FRANCO Y ESTEBAN, SUSANA BEATRIZ
Revista:
AMEGHINIANA
Editorial:
Asociación Paleontológica Argentina
Referencias:
Lugar: Buenos Aires; Año: 2007 p. 597 - 620
ISSN:
0002-7014
Resumen:
Abstract. TRILOBITES FROM THE VOLCANCITO FORMATION (FILO AZULMEMBER, LATE CAMBRIAN) OF THE FAMATINA SYSTEM,
LA RIOJA, ARGENTINA: SYSTEMATIC AND PALEOENVIRONMETS. The Filo Azul Member of the Volcancito Formation
(Famatina range, La Rioja, Argentina) consists of a lower part (30 m) of thinly laminated marls and calcareous shales
with intercalations of fine-grained sandstones, a middle part (85 m) of massive middle to thick-grained calcareous
sandstones, and an upper part (50 m) of shales with interbedded layers of fine sandstones. Previous studies on
trilobites, graptolites and conodonts assigned the section to the Upper Cambrian-Lower Ordovician. The lower portion
of the member (Parabolina frequens argentina Biozone, lower part) contains a diverse trilobite fauna that was studied
by Harrington and Leanza in the 1950s. Since then, new collections have been obtained, which are the subject
of the present study. New polymerid trilobites, originally described on the basis of scarce material, are re-illustrated
(Onychopyge riojana Harrington, Asaphellus riojanus Harrington and Leanza, Rhadinopleura eurycephala Harrington
and Leanza, Plicatolina scalpta Harrington and Leanza) and the assignations of several taxa are reconsidered
(Angelina cf. hyeronimi (Kayser), Parabolinella sp. 1, Parabolinella sp. 2, Pseudokainella tosellii sp. nov., Conophrys sp.)
(since the agnostoids have been recently revised, they are not included in this study). The fauna comprises several
endemic species. On the other hand, the occurrence of Parabolina (Neoparabolina) frequens (Barrande) allows correlated
the outcrop to with other Upper Cambrian sections. The abundance of nutrients in the sea bottom must have favoured
the development of a diverse trilobite community, which included different morphotypes and feeding habits.
Several taxa were especially adapted to live under low-oxygen conditions, probably in symbiosis with sulfur
bacteria.TRILOBITES FROM THE VOLCANCITO FORMATION (FILO AZULMEMBER, LATE CAMBRIAN) OF THE FAMATINA SYSTEM,
LA RIOJA, ARGENTINA: SYSTEMATIC AND PALEOENVIRONMETS. The Filo Azul Member of the Volcancito Formation
(Famatina range, La Rioja, Argentina) consists of a lower part (30 m) of thinly laminated marls and calcareous shales
with intercalations of fine-grained sandstones, a middle part (85 m) of massive middle to thick-grained calcareous
sandstones, and an upper part (50 m) of shales with interbedded layers of fine sandstones. Previous studies on
trilobites, graptolites and conodonts assigned the section to the Upper Cambrian-Lower Ordovician. The lower portion
of the member (Parabolina frequens argentina Biozone, lower part) contains a diverse trilobite fauna that was studied
by Harrington and Leanza in the 1950s. Since then, new collections have been obtained, which are the subject
of the present study. New polymerid trilobites, originally described on the basis of scarce material, are re-illustrated
(Onychopyge riojana Harrington, Asaphellus riojanus Harrington and Leanza, Rhadinopleura eurycephala Harrington
and Leanza, Plicatolina scalpta Harrington and Leanza) and the assignations of several taxa are reconsidered
(Angelina cf. hyeronimi (Kayser), Parabolinella sp. 1, Parabolinella sp. 2, Pseudokainella tosellii sp. nov., Conophrys sp.)
(since the agnostoids have been recently revised, they are not included in this study). The fauna comprises several
endemic species. On the other hand, the occurrence of Parabolina (Neoparabolina) frequens (Barrande) allows correlated
the outcrop to with other Upper Cambrian sections. The abundance of nutrients in the sea bottom must have favoured
the development of a diverse trilobite community, which included different morphotypes and feeding habits.
Several taxa were especially adapted to live under low-oxygen conditions, probably in symbiosis with sulfur
bacteria.A RIOJA, ARGENTINA: SYSTEMATIC AND PALEOENVIRONMETS. The Filo Azul Member of the Volcancito Formation
(Famatina range, La Rioja, Argentina) consists of a lower part (30 m) of thinly laminated marls and calcareous shales
with intercalations of fine-grained sandstones, a middle part (85 m) of massive middle to thick-grained calcareous
sandstones, and an upper part (50 m) of shales with interbedded layers of fine sandstones. Previous studies on
trilobites, graptolites and conodonts assigned the section to the Upper Cambrian-Lower Ordovician. The lower portion
of the member (Parabolina frequens argentina Biozone, lower part) contains a diverse trilobite fauna that was studied
by Harrington and Leanza in the 1950s. Since then, new collections have been obtained, which are the subject
of the present study. New polymerid trilobites, originally described on the basis of scarce material, are re-illustrated
(Onychopyge riojana Harrington, Asaphellus riojanus Harrington and Leanza, Rhadinopleura eurycephala Harrington
and Leanza, Plicatolina scalpta Harrington and Leanza) and the assignations of several taxa are reconsidered
(Angelina cf. hyeronimi (Kayser), Parabolinella sp. 1, Parabolinella sp. 2, Pseudokainella tosellii sp. nov., Conophrys sp.)
(since the agnostoids have been recently revised, they are not included in this study). The fauna comprises several
endemic species. On the other hand, the occurrence of Parabolina (Neoparabolina) frequens (Barrande) allows correlated
the outcrop to with other Upper Cambrian sections. The abundance of nutrients in the sea bottom must have favoured
the development of a diverse trilobite community, which included different morphotypes and feeding habits.
Several taxa were especially adapted to live under low-oxygen conditions, probably in symbiosis with sulfur
bacteria.Parabolina frequens argentina Biozone, lower part) contains a diverse trilobite fauna that was studied
by Harrington and Leanza in the 1950s. Since then, new collections have been obtained, which are the subject
of the present study. New polymerid trilobites, originally described on the basis of scarce material, are re-illustrated
(Onychopyge riojana Harrington, Asaphellus riojanus Harrington and Leanza, Rhadinopleura eurycephala Harrington
and Leanza, Plicatolina scalpta Harrington and Leanza) and the assignations of several taxa are reconsidered
(Angelina cf. hyeronimi (Kayser), Parabolinella sp. 1, Parabolinella sp. 2, Pseudokainella tosellii sp. nov., Conophrys sp.)
(since the agnostoids have been recently revised, they are not included in this study). The fauna comprises several
endemic species. On the other hand, the occurrence of Parabolina (Neoparabolina) frequens (Barrande) allows correlated
the outcrop to with other Upper Cambrian sections. The abundance of nutrients in the sea bottom must have favoured
the development of a diverse trilobite community, which included different morphotypes and feeding habits.
Several taxa were especially adapted to live under low-oxygen conditions, probably in symbiosis with sulfur
bacteria.Onychopyge riojana Harrington, Asaphellus riojanus Harrington and Leanza, Rhadinopleura eurycephala Harrington
and Leanza, Plicatolina scalpta Harrington and Leanza) and the assignations of several taxa are reconsidered
(Angelina cf. hyeronimi (Kayser), Parabolinella sp. 1, Parabolinella sp. 2, Pseudokainella tosellii sp. nov., Conophrys sp.)
(since the agnostoids have been recently revised, they are not included in this study). The fauna comprises several
endemic species. On the other hand, the occurrence of Parabolina (Neoparabolina) frequens (Barrande) allows correlated
the outcrop to with other Upper Cambrian sections. The abundance of nutrients in the sea bottom must have favoured
the development of a diverse trilobite community, which included different morphotypes and feeding habits.
Several taxa were especially adapted to live under low-oxygen conditions, probably in symbiosis with sulfur
bacteria.Plicatolina scalpta Harrington and Leanza) and the assignations of several taxa are reconsidered
(Angelina cf. hyeronimi (Kayser), Parabolinella sp. 1, Parabolinella sp. 2, Pseudokainella tosellii sp. nov., Conophrys sp.)
(since the agnostoids have been recently revised, they are not included in this study). The fauna comprises several
endemic species. On the other hand, the occurrence of Parabolina (Neoparabolina) frequens (Barrande) allows correlated
the outcrop to with other Upper Cambrian sections. The abundance of nutrients in the sea bottom must have favoured
the development of a diverse trilobite community, which included different morphotypes and feeding habits.
Several taxa were especially adapted to live under low-oxygen conditions, probably in symbiosis with sulfur
bacteria.Angelina cf. hyeronimi (Kayser), Parabolinella sp. 1, Parabolinella sp. 2, Pseudokainella tosellii sp. nov., Conophrys sp.)
(since the agnostoids have been recently revised, they are not included in this study). The fauna comprises several
endemic species. On the other hand, the occurrence of Parabolina (Neoparabolina) frequens (Barrande) allows correlated
the outcrop to with other Upper Cambrian sections. The abundance of nutrients in the sea bottom must have favoured
the development of a diverse trilobite community, which included different morphotypes and feeding habits.
Several taxa were especially adapted to live under low-oxygen conditions, probably in symbiosis with sulfur
bacteria.Parabolina (Neoparabolina) frequens (Barrande) allows correlated
the outcrop to with other Upper Cambrian sections. The abundance of nutrients in the sea bottom must have favoured
the development of a diverse trilobite community, which included different morphotypes and feeding habits.
Several taxa were especially adapted to live under low-oxygen conditions, probably in symbiosis with sulfur
bacteria.