Macro and microphytofossils study of the Itararé Subgroup at Km 96 of Bandeirantes highway, Campinas municipality, SP

MACRO AND MICROPHYTOFOSSILS STUDY OF THE ITARARÉ SUBGROUP AT KM 96 Of BANDEIRANTES HIGHWAY, CAMPINAS MUNICIPALITY, SP^*

PAULA G. C. AMARAL¹, FRESIA RICARDI-BRANCO², PAULO A. DE SOUZA³, MARY E. C. BERNARDES-DE-OLIVEIRA1,⁴

¹Instituto de Geociências, USP, São Paulo, SP.

²Instituto de Geociências, UNICAMP, Campinas, SP.

³Instituto Geológico, Secretaria do Meio Ambiente, São Paulo, SP.

⁴Centro de Ciências Exatas e Tecnológicas (CCET), UnG, Guarulhos, SP.

Presented by ANTONIO C. ROCHA-CAMPOS

Outcrops recently exposed by construction at Km 96 of Bandeirantes highway, near Campinas, SP, have yielded a phytofossiliferous assemblage of abundant megaspores, bryophytic axes, unidentified caulinar axes and palynomorphs in massive dark-gray mudstones, with rhythmic intercalations of very bioturbated fine and very fine sandstone of the Itararé Subgroup. The following taxa have been identified:

Megaspores - Sublagenicula brasiliensis, Sublagenicula sinuata, Calamospora sp. and Trileites tenuis;

Palynomorphs - Puntactisporites gretensis, Psomospora detecta, Cristatisporites rollerii, Cristatisporites morungavensis, Cristatisporites spinosus, Cristatisporites sp. 1, Cristatisporites sp. 2, Lundbladispora riobonitensis, Vallatisporites ciliaris, Vallatisporites vallatus, Vallatisporites sp., Raistrickia rotunda, Raistrickia pinguis, Plicatipollenites malabarensis, Plicatipolletines gondwanensis, Potonieisporites brasiliensis, Potonieisporites novicus, Potonieisporites magnus, Potonieisporites neglectus, Limitisporites rectus and Limitisporites hexagonales;

Macrophytofossils - aff. Dwykea sp.

This phytofossiliferous association suggests the existence of a possibly tundra-like vegetal covering, consisting of bryophytes, lycophytes, sphenophytes and gymnosperms (probable pteridospermaleans and coniferaleans). The bryophytes may have occupied coastal rocks; the lycophytes, coastal plains; the sphenophytes, river banks; and the pteridospermaleans and coniferaleans, higher continental areas.

As for the depositional environment, we can infer its proximity to the continent, based on the abundance of megaspores; on the similarity of pollen grain and spore frequencies, including preserved tetrads; and on the delicate leafy caulidium of the bryophytes.

These strata belong to the Ahrensisporites cristatus Interval Zone, which is considered as Westphalian in age (Souza PA.2000, unpublished Doctoral Thesis, IGc/USP), of the lower portion of the Itararé Subgroup. — ( December 8, 2000 )

^*

Supported by: FAPESP 97/03639-8.

Publication Dates

• Publication in this collection
  05 Oct 2001
• Date of issue
  Sept 2001