Genetic relationships between ferralsols, podzols and white kaolin in Amazonia

Abstract

Summary White kaolin has frequently been observed to be associated with ferralsol‐podzol soil systems in Amazonia. In order to evaluate whether such systems favour kaolin genesis and to identify the associated genetic processes, we studied soil organization, mineralogy and groundwater properties of a ferralsol‐podzol soil system with white kaolin located in the High Rio Negro Basin, Brazil. We found that the kaolin was situated near the ferralsol‐podzol transition and that its thickness was related to the depth of landscape incision by regressive erosion. The kaolin was characterized by silicon, iron and titanium (Ti) leaching and aluminium (Al) absolute accumulation. The groundwater that percolates from the podzol to the kaolin can enhance kaolinite precipitation, by supplying Al originating from kaolinite dissolution in the overlying Bh, and kaolin bleaching, by low pH and Eh of the percolating waters favouring iron reduction. The system dynamics imply that the quartz dissolution rate in the kaolin is of at least the same order of magnitude as the kaolinite dissolution rate in the overlying Bh. Within the whole system, Ti appeared to be very mobile.

Kaolinite dating from Acrisol and Ferralsol: A new key to understanding the landscape evolution in NW Amazonia (Brazil)

“…In the Curicuriari Basin, both Ferralsol and Acrisol can be replaced by Podzols which are observed to form at the center of the plateaus over the inundated plains and depressions (Dubroeucq et Volkoff, 1998;Do Nacscimento et al, 2004;Fritsch et al, 2011 and ref. therein;Ishida et al, 2014) and over the slopes of river incisions (Lucas et al, 1996). Moreover, it is not excluded that the transformation of an old Ferralsol into the present-day Acrisol, described in the model of Taitson Bueno (2009), occurred earlier than 6 Ma.…”

“…These younger Miocene ages were interpreted as reflecting kaolinite dissolution and recrystallization under the action of supergene weathering fronts in the regolith. The Ferralsol/Podzol (Lucas et al, 1996;Dubroeucq et Volkoff, 1998;Do Nascimento et al, 2004;Ishida et al, 2014) or red to yellow Ferralsols transitions (Fritsch et al, 2005;Balan et al, 2007) have been studied in the Amazon basin. The "yellowing process" of Ferralsols proceeds with the progressive replacement of kaolinite, hematite and Al-poor goethite by Alrich goethite and gibbsite presumably resulting from the action of the present-day humid climate (Fritsch et al, 2002;2005).…”

Combined dating of goethites and kaolinites from ferruginous duricrusts. Deciphering the Late Neogene erosion history of Central Amazonia

“…1B. Those surfaces are mainly composed of laterites developed on Paleozoic to the Archean basement and on clastic sedimentary rocks (Fritsch et al, 2011;Ishida et al, 2014;Lucas et al, 2012). A scattered patchwork of a few absolute ages is available for lateritic formations from the central Amazonia (Fig.…”

Avaliação da sensibilidade à mineralização e estudo detalhado da matéria orgânica em Espodossolos da alta bacia do Rio Negro, Amazonas

“…Compreendendo os municípios de São Gabriel da Cachoeira, Santa Isabel do Rio Negro e Barcelos, os estudos de solos na região do alto Rio Negro se iniciaram por volta dos anos 60 (DAY, 1959) e apenas nos anos 70 foi realizado um levantamento mais completo pela EMBRAPA-SNLCS e pelo projeto RADAMBRASIL. Posteriormente outros trabalhos foram desenvolvidos com o intuito de conhecer o funcionamento e estrutura desses solos, assim como compreender sua dinâmica evolutiva (DUBROEUCQ;DUBROEUCQ;FAURE, 1999;MAFRA et al, 2002;NASCIMENTO et al, 2004;MONTES et al, 2007;BARDY et al, 2008;NASCIMENTO et al, 2008;ISHIDA et al, 2014;DE PAULA, 2015;PEREIRA et al, 2015;SANTOS et al, 2015a;TADINI et al, 2015).…”

“…A absorção UV -Vis para as amostras de solos foi realizada, inicialmente, pela preparação de solução de 200 mg L -1 , utilizando 2 mg da amostra de AH em 10 mL NaHCO 3 0,05 mol L -1 e, posteriormente diluídas, afim de obter solução de 10 mg L -1 FAURE, 1999;MAFRA et al, 2002;NASCIMENTO et al, 2004;MONTES et al, 2006;BARDY et al, 2008;NASCIMENTO et al, 2008;, ISHIDA et al, 2014PEREIRA et al, 2015;TADINI et al, 2015;SANTOS et al, 2015a, DE PAULA, 2015 (GOUVEIA et al, 1999;SILVA et al, 2007). PICCOLO et al, 1994;LUIZÃO et al, 2004), enquanto em florestas temperadas esse valor pode ser altamente variável (HILL; SHACKLETON, 1989) sendo que as taxas de transformação de N podem variar entre os diversos tipos de solo dentro da mesma bacia hidrográfica (VAN MIEGROET et al, 1990;GARTEN et al, 1994 (MARIOTTI et al, 1980;FRY, 1988;SHEARER et al, 1978;TIESSEN et al, 1984;NARDOTO, 2005 (MARTINELLI et al, 1996;OMETTO et al, 2006).…”