Abrangência espacial e temporal da morfogênese e pedogênese no Planalto de Palmas (PR) e Água Doce (SC): subsídio ao estudo da evolução da paisagem quaternára

Abstract

This work presents the space and temporary inclusion of the morfogênese and pedogênese in Palmas (PR) and Água Doce (SC) Plateau: subsidy to the study of the evolution of the quaternary landscape, starting from five stratigraphic sections, as well as the use of preponderant information, established by Paisani et al. (submitted a) in the section HS1. This survey included descriptions of lithological and pedological units, along with laboratory tests, such as granulometry, carbon content and organic matter, micromorphological description and dating of 14C. By means of the description, it was identified in the sections deposits of colluvium, colluvial-alluvial, buried grounds (fluvisol Neosoils) and paleochannels of 1st and 2nd order filled out, verified in sections HS1, HS2, HS4 and HS6. The results showed, in the sections, stratigraphic records with ages of Higher Pleistocene to the Holocene, referring to the Marine Isotopic stages 3, 2 and 1. As seen in paleosoils verified in the sections present ages dated from 41,000 to 25,000 years AP, corresponding to the Higher Pleistocene, can be concluded that the environment in this period, both valley bottom and slope, was in the environmental balance (stability) promoting the pedogenesis, with formation of fluvisol Neosoils, with humic A horizon, similar to other localities, confirming a stability phase of a regional stamp. In the limit Pleistocene / Holocene, it was verified alternating phases of morphogenesis pedogenesis, responsible by the formation of colluvial units, colluvialalluvial and pedological horizons. In the beginning of the Holocene, it was verified an intense phase of morphogenesis, with erosion (degradation) of the hillsides and completion (aggradation) of the valleys of low hierarchical order, lasted until about 1,000 years AP. After 1,000 years AP, corresponding to the last millennium, the environment enter in balance (stability) with the performance of pedogenesis, forming Neosoils with humic A horizon. Overall, the surveying of the stratigraphic record in the study area revealed important information about the events that were present in its evolution. These events indicate that the landscape has its evolution related to alternated phases of stability / instability, with degradation / aggradation and pedogenesis with formation of Neosoils.