Cross-polarized light as an imaging technique for graptolites

Abstract

Photography using cross-polarized light is a standard technique for certain types of fossils such as Burgess Shale material; however, the technique has not been used for photography of graptolites. Here we demonstrate that cross-polarized illumination is useful for obtaining high-quality images of graptolites. The technique can also facilitate visualization of fusellar banding, allowing fossils of uncertain affinity to be identified as graptolites. Lucy A. Muir [ lucy@asoldasthehills.org ], Department of Natural Sciences, Amgueddfa Cymru – National Museum Wales, Cathays Park, Cardiff CF10 3NP, UK; Lucy M.E. McCobb [ Lucy.McCobb@museumwales.ac.uk ], Department of Natural Sciences, Amgueddfa Cymru – National Museum Wales, Cathays Park, Cardiff CF10 3NP, UK; Yuandong Zhang* [ ydzhang@nigpas.ac.cn ], CAS Key Laboratory of Economic Geology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, 39 East Beijing Road, Nanjing 210008, PR China; *also affiliated with University of Chinese Academy of Sciences, Beijing 100049, PR China.