English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/72935
Share/Impact:
Statistics
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Title

The nature and significance of variations in gypsum crystal morphology in dry lake basins

AuthorsMees, Florias; Castañeda del Álamo, Carmen ; Herrero Isern, Juan ; Ranst, Eric van
Issue DateJan-2012
PublisherSEPM (Society for Sedimentary Geology)
CitationMees F, Castañeda C, Herrero J, Van Ranst E. The nature and significance of variations in gypsum crystal morphology in dry lake basins. Journal of Sedimentary Research 82 (1): 37-52 (2012)
AbstractDepressions in semiarid regions with a gypsiferous geological substrate commonly contain highly gypsiferous sediments, with gypsum that formed either as a synsedimentary precipitate during perennial or ephemeral lake stages or as a diagenetic precipitate during saline mudflat stages. The dry to ephemeral lake basins of the Monegros region in northern Spain are depressions of this type and provide a unique opportunity to examine whether and how conditions of gypsum formation are reflected by gypsum crystal morphology, yielding information that can contribute to a correct interpretation of the depositional environment of gypsum in ancient and modern formations. In most lake basins of the study area, the sediment fill consists of a similar sequence of three lithological units. The lower unit includes fragmented gypsum crystals in some basins, recording clastic reworking, and in other depressions it contains large lenticular crystals, formed as phreatic diagenetic precipitates. The middle unit typically contains synsedimentary gypsum with a non-lenticular morphology, modified by postdepositional processes, but it also comprises synsedimentary lenticular gypsum in some basins. In the upper unit, separated from the underlying interval by a marked hiatus, both synsedimentary and diagenetic gypsum are present, the former including layered gypsum deposits with features such as grading and variations in crystal morphology. The results show that a non-lenticular crystal habit of gypsum occurring within the groundmass (sediment matrix) indicates synsedimentary precipitation. In contrast, a lenticular crystal habit cannot be used in isolation as an indicator of the environment in which the gypsum initially precipitated. Unambiguously late-diagenetic gypsum includes fine-grained precipitates in voids created by soil fauna. These infillings consist of initially non-lenticular crystals, with a tabular-prismatic habit, recording that conditions promoting lenticular crystal growth do not always prevail outside the groundmass in soil-related settings and illustrating the importance of knowing the context of analyzed gypsum occurrences at the scale of a sample.
Description16 Pags., 11 Figs., 4 Tabls.
Publisher version (URL)http://dx.doi.org/ 10.2110/jsr.2012.3
URIhttp://hdl.handle.net/10261/72935
DOI10.2110/jsr.2012.3
ISSN1527-1404
Appears in Collections:(EEAD) Artículos
Files in This Item:
File Description SizeFormat 
HerreroJ_link-JSedimentRes_2012.pdf63,62 kBAdobe PDFThumbnail
View/Open
Show full item record
Review this work
 

Related articles:


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.