Easily altered minerals and reequilibrated fluidinclusions provide extensive records of fluid andthermal history: gypsum pseudomorphs of the TeraGroup, Tithonian-Berriasian, Cameros Basin

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González Acebrón, Laura and Goldstein, Robert H. and Arribas Mocoroa, José (2012) Easily altered minerals and reequilibrated fluidinclusions provide extensive records of fluid andthermal history: gypsum pseudomorphs of the TeraGroup, Tithonian-Berriasian, Cameros Basin. Central European Journal of Geosciences, 4 (2). pp. 246-260. ISSN 1896-1517

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Official URL: https://doi.org/10.2478/s13533-011-0055-x




Abstract

This study reports a complex fluid and thermal history using petrography, electron microprobe, isotopic analysisand fluid inclusions in replacement minerals within gypsum pseudomorphs in Tithonian-Berriasian lacustrine de-posits in Northern Spain. Limestones and dolostones, formed in the alkaline lakes, contain lenticularly shapedgypsum pseudomorphs, considered to form in an evaporative lake. The gypsum was replaced by quartz andnon-ferroan calcite (Ca-2), which partially replaces the quartz. Quartz contains solid inclusions of a preexistingnon-ferroan calcite (Ca-1), anhydrite and celestine.High homogenization temperatures (Th) values and inconsistent thermometric behaviour within secondary fluidinclusion assemblages in quartz (147-351◦C) and calcite (108-352◦C) indicate high temperatures after precipita-tion and entrapment of lower temperature FIAs. Th are in the same range as other reequilibrated fluid inclusionsfrom quartz veins in the same area that are related to Cretaceous hydrothermalism.Gypsum was replaced by anhydrite, likely during early burial. Later, anhydrite was partially replaced by Ca-1associated with intermediate burial temperatures. Afterward, both anhydrite and Ca-1 were partially replacedby quartz and this by Ca-2. All were affected during higher temperature hydrothermalism and a CO2-H2O fluid.Progressive heating and hydrothermal pulses, involving a CO2-H2O fluid, produce the reequilibration of the FIAs,which was followed by uplift and cooling


Item Type:Article
Uncontrolled Keywords:Fluid inclusions, ypsum pseudomorphs, Cameros Basin, thermal reequilibration.
Subjects:Sciences > Geology > Mineralogy
ID Code:65046
Deposited On:23 Apr 2021 15:32
Last Modified:26 Apr 2021 07:47

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