Toggle Main Menu Toggle Search

Open Access padlockePrints

Identifying biogenic silica: Mudrock micro-fabric explored through charge contrast imaging

Lookup NU author(s): Carol Mahoney, Professor Thomas Wagner


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


© 2017 by Walter de Gruyter Berlin/Boston 2017. Visual inspection (optical microscope point counting) and silica abundance show that laminated shale from the Late Cretaceous of Colombia contains high levels of detrital quartz silt and sand particles. Closer examination using the charge contrast imaging (CCI) technique, however, illustrates that much of the quartz is authigenic micro-quartz, and thus not exclusively of detrital origin. In addition, many "sand" grains that otherwise appear to represent simple detrital quartz particles are actually of biogenic origin, representing the tests of agglutinated foraminifera, formed from cemented silt-sized quartz particles. Finally, CCI shows that original detrital grains have undergone authigenic modification, with both syntaxial overgrowths and micro-quartz. Without recognition of these features, the relative proportion of detrital quartz (sand) would otherwise be greatly overestimated, with important implications for environmental interpretation. Furthermore, the recognition of biogenic structures, including agglutinated foraminifera, provides additional environmental information that otherwise could be easily overlooked.

Publication metadata

Author(s): Buckman J, Mahoney C, Marz C, Wagner T, Blanco V

Publication type: Article

Publication status: Published

Journal: American Mineralogist

Year: 2017

Volume: 102

Issue: 4

Pages: 833-844

Online publication date: 03/04/2017

Acceptance date: 26/10/2016

ISSN (print): 0003-004X

ISSN (electronic): 1945-3027

Publisher: Mineralogical Society of America


DOI: 10.2138/am-2017-5797


Altmetrics provided by Altmetric