RT Journal Article
T1 Pedogenetic Calcretes In Early Syn-Rift Alluvial Systems (Upper Jurassic, West Cameros Basin), Northern Spain
A1 Sacristán Horcajada, Sara
A1 Arribas, Eugenia
A1 Más Mayoral, Ramón
AB Exceptional pedogenetic calcretes occur in the earliest syn-rift sedimentary record (Tithonian) of the west Cameros Basin. These calcretes show different types of pedogenetic facies (nodular, massive, laminar, and brecciated–pisolithic) and microfabrics: brecciated intraclasts, carbonate nodules, coated clasts and grains, etched quartz grains, rhizocretions, pedotubules and fragmented alveolar–septal structures. In addition, calcrete fragments have been observed in the conglomerate and sandy channelized deposits that form the alluvial systems, indicating the reworking of previous calcrete deposits. Calcrete facies appear organized in several sequences developed over different architectural elements in three different types of alluvial systems. The type of calcrete sequence is different depending on the architectural arrangement of each alluvial-fan system. Laminar (L (MN)–S) and brecciated–pisolithic (BP (L)–S) calcrete sequences are predominant in the alluvial sedimentary record of poorly channelized alluvial systems. These calcretes are thick, morphologically complex, and laterally continuous, due to the formation of long-term stable subaerial surfaces favored by the intermittent behavior of the alluvial systems. Massive-nodular (M (N)–S) and laminar (L (MN)–S) sequences are predominant in highly channelized alluvial systems and develop only locally in interchannel or floodplain areas where sedimentation stops temporally. Calcrete sequences in the distributive fluvial fan systems can be considered as poorly developed, being massive-nodular (M (N)–S) and nodular (N–S). After analyzing the location of these calcrete sequences in the studied record and their genesis and environmental significance, their variations can be related to different autocyclic factors such as sedimentation rate, channel network organization, texture of the host sediment, and water-table influence. Also three main allocyclic factors such as climate, tectonics, and drainage area controlled the carbonate sedimentation and therefore the development of the calcretes.
PB Society for Sedimentary Geology
SN Issn: 1527-1404)
YR 2016
FD 2016-08
LK https://hdl.handle.net/20.500.14352/18821
UL https://hdl.handle.net/20.500.14352/18821
LA eng
NO Ministerio de Ciencia e Innovación (MICINN)
NO Universidad Complutense de Madrid
NO Geosciences Institute (IGEO-CSIC)
NO FPU (Formación del Profesorado Universitario)
DS Docta Complutense
RD 7 may 2024