OCORRÊNCIA DA FORMAÇÃO PIRABAS (MIOCENO INFERIOR) NA BACIA DE BARREIRINHAS, MARANHÃO

FERREIRA CÂNDIDO SIMÕES, GONZÁLEZ BALDOMERO BARCIA, FRANCISCO BENEDICTO HUMBERTO RODRIGUES
1973 Revista Brasileira de Geociências  
A new o utcro p of the Pira bas Formation was fou nd in th e right bank of the igar ape Marcian o, 3.5 km so uth of Ca cte, county of Pinh eiro cia Cruz. Ficld o bservations a nd exa mina tion of the collected sa mples lead t he a uthors to desc ribe a new geo logic sett ing of the for m a tion, insid e th e Barr eirinh as basin . M oreover , the fossil content includes specimens of genus Orthaula x, a ga stro pod cons idered as a good ind ex-fossil lo r a great nu m ber of Lower Mi ocene fo rm
more » ... ower Mi ocene fo rm a tion s of the Caribbea n Pro vin ce. A spec ial kind of pyri te was foun d, proba bly bio geni c, resulting from meta somat ic processes affecti ng ca lcium ca rbo na tes. INTRODUCAO Em sctcm b ro d e 1969, tivemos a oportu nidadc de exc ursiona r pel o Estado do M aranh a o e na eve ntua lidadc, grac;as ao aux ilio ofcrce ido pcla Pet ro br as (setares Helem , PA , e Sao Lu is,~1A) na form a de tra nspo rte m a rtri mo, pudcmos eon firma r as informacocs prestadas pelo gc61ogo daqucla cm pr csa, Joel Ca rneiro de Castro , quan to a urn novo aflora me nto da Forma ca o Pirabas, situado na margem d irc ita do iga rapc Ma rcia no, a 3,5 km S d o luga rejo Caete, no mun ici pio de Primeira Cruz, pert encendo, Obscrv<lc; ao . As cspccics assinal ada s co m astcri sco tern aqUi () sell pn mclro rcgistro na Formac ao Pir abas.
doi:10.25249/0375-7536.19736067 fatcat:xb7rnslzrnfdrmjxarkmmzc7j4