Consequencias do frio durante o Cuaternario na faiza litoral do Minho (Portugal)

Abstract

[Resumo] Estruturas diapíricas de pequena dimensçao nun depósito de terraço fluvial do vale do cávado (Penida, Areias de Vilar), injecçao de cascalbo a través de um depósito de cascalho de urm terraço marinho (Bouro, Marinhas, Esposende), seixos can eixo maior vertical ou bastante inclinado incluídos ero depósitos dos terraços da faixa litoral minhota, seixos polifacetados ou rolados can facetas, com arestas sinuosas, superfícies picotadas, polidas, estriadas, que denunciarn urna forte eolizaçao, e areias eólicas, levam a supor que, durante o Wünn, o Minho, bacias de drenagem e faixa litoral, esteve sugeite a uro sistena periglaciar. Estes factos, c:x:nparados can as conclusOes paleoclimáticas do Quatemário, apoiadas nas interpretac#5es das variaçoes de forarniníferos e neutros critérios paleoclimáticos de sondagens realizadas no fundo do Atlantico Norte, que situam a frente polar a latitl.rles mais baixas do· que as do Minho (CLIMAT PROJECT MEMBERS" 1976, RIDDD1AN e McINrYRE 1981), levarn a considerar aquelas consequencias periglaciares caro tenda ocorrido no intervalo de tempo:> 20.000-13.000 BP (anos antes da actualidade)

[Abstract] Diapir structures of little dimension in fluvial terrace deposits of Cavado valley (Penida, Areias de Vilar) , injection of gravel through the gravel of a marine terrace (Bouro, Marinhas, Esposende), pebbles with greater axis standing vertical or very 'inclined enclosed in top of terrace deposits of coastal region of Minho, polifaceted pebbles or rolled with facets, sinuous edge, pricked,snr:x>th, grooved surface, that denunciate a strong effect of wind wear and wi.rrl 'WOm sands lead te think that, during the Wüml, the Minho, drainage bassins arx1 coastal region, was exposed te a periglacial systan. These facts, conpared with palaeoclimatic oonclusions on Quaternary, supported by the interpretations of rate of change of planktonic foraminiferal species and other palaeclimatic criterious of drilling oores carried out in North Atlantic bottan, that place the polar front in laver latitudes them those of Minho (CLIMAT PROJECT MEMBERS 1976, RUDDIMAN and McINTIYRE 1981) lead do suppose those periglacial consequences as happened in the tille between 20 000 13000 BP.