A change from warm/humid to cold/dry climate conditions recorded in lower Barremian clay-dominated continental successions from the SE Iberian Chain (NE Spain)

摘要: Abstract A combined facies and clay mineralogy analysis of the continental succession recorded in lower part Blesa Formation (early Barremian, Oliete subbasin, NE Spain) allowed us to specify palaeoclimatic palaeoenvironmental conditions under which this sedimentary record originated. Six outcrops including clays, clays/marls dm-thick interbedded palustrine-lacustrine limestone levels were logged sampled for X-ray diffraction optical electron microscopy analysis. The consist red clays with abundant ferruginous pisoids (1–5 mm size) macropisoids (>5 mm), whereas intermediate upper are ochre violet few or no pisoids. normally a nucleus cortex made up several layers. Some have fragment previous pisoid acting as nucleus, indicating local re-working processes. Both formed by hematite, goethite, variable contents kaolinite, minor proportions ilmenite. Their texture show an in-situ growth. Interbedded beds within clay- clay/marl-dominated micrite, microsparite sparite. These limestones cemented kaolinite they also pisoids, occurrence edaphic lowest calcite content highest anatase, diaspore, goethite content. By contrast, higher illite Smectite is only detected clays/marls. This mineral association characteristic lateritic palaeosols, warm humid conditions. Kaolinite smectite textures indicate that authigenic, may be detrital origin. upward decrease diaspore content, along increase quartz presence illite, reflect change from drier colder during early Barremian studied area.