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| Titel |
New insights on the occurrence of peperites and sedimentary deposits within the silicic volcanic sequences of the Paraná Magmatic Province, Brazil |
| VerfasserIn |
A. C. F. Luchetti, A. J. R. Nardy, F. B. Machado, J. E. O. Madeira, J. M. Arnosio |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 5, no. 1 ; Nr. 5, no. 1 (2014-03-10), S.121-130 |
| Datensatznummer |
250115258
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| Publikation (Nr.) |
 copernicus.org/se-5-121-2014.pdf |
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| Zusammenfassung |
| The PMP (Paraná Magmatic Province) is characterized by lava flows of the
Early Cretaceous Serra Geral Formation which covers about 75% of the
Paraná Basin (southern and southeastern Brazil), composed of a thick (up
to 1600 m) volcanic sequence formed by a succession of petrographically and
geochemically distinct units of basic and silicic composition. The whole
package must have been emplaced during approximately 3 million years of nearly
uninterrupted activity. A few aeolian sandstone layers, indicating arid
environmental conditions (the Botucatu Formation), are interlayered in the
lower basalts. Above the basalts, the Palmas and Chapecó Members are
composed of silicic volcanic rocks (quartz latites, dacites, rhyodacites and
rhyolites) and basalts. This paper presents new evidence of sedimentation
episodes separating silicic volcanic events, expressed by the occurrence of
sedimentary deposits. Interaction between the volcanic bodies and the coeval
unconsolidated sediments formed peperites. The sediments were observed
between basaltic lava flows and silicic rocks or interlayered in the Palmas-type rocks, between the Chapecó-type rocks and overlying basaltic flows,
between silicic bodies of the Palmas and Chapecó types, and interlayered
within Palmas-type units. The observed structures indicate that the sediments
were still wet and unconsolidated, or weakly consolidated, at the time of
volcanism, which, coupled with the sediment features, reflect environmental
conditions that are different from those characterizing the Botucatu arid
conditions. |
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