Visualization and identification of components in a gigantic spherical dolomite concretion by Raman imaging in combination with MCR or CLS methods.

The combination of Raman imaging and multivariate curve resolution (MCR) or classical least squares (CLS) has allowed us to explore the distribution and identification of components in a gigantic spherical dolomite concretion. It has been found by the MCR and CLS analyses of imaging data that the concretion contains dolomite, kerogen, anatase, quartz, plagioclase, and carbon materials with considerably large distribution of dolomite. The existence of these components has also been confirmed by the point-by-point analysis of imaging data. The distributions of these components were clearly observed by Raman images. Of note is that the amount of carbon materials is considerably large, and they are buried among the matrix sedimentary grains in the concretion, suggesting that there exist soft tissues with biological origin. Moreover, one of the loading spectra of CLS shows intense bands in the region of 3000-2800 cm-1, and bands at ca. 1658, ca. 1585, 1455, 1323, and 1261 cm-1. These bands indicate the existence of decomposed organic materials in the concretion. Raman imaging of concretions provides direct evidence that concretions are of biological organic origin.

Fossil decapods from the Upper Quaternary in Shinjima Island in Kagoshima, Kyushu, Japan, and description of a new species of ghost shrimp (Axiidea, Eucalliacidae).

Five species of decapod crustaceans, including Calliax nishiki sp. nov. (Axiidea, Eucalliacidae) and Carcinoplax longimana (de Haan), are described from the upper part of the Moeshima Silt Bed (latest Pleistocene to Holocene: ca 13,000 to 8,000 cal BP). Ten decapods, including Laticallichirus grandis (Karasawa Goda) and Ebalia tuberculosa (A. Milne-Edwards) are described from the Moeshima Shell Bed (Holocene: ca 8,000 to 2,000 cal BP). Calliax nishiki is abundant and Carcinoplax longimana is common in the decapod assemblage of Moeshima Silt Bed. The new species of Calliax seems to have dispersed around the deep marine setting with a reducing environment. The decapod assemblage of the Moeshima Shell Bed is characterized by a predominance of L. grandis. The present record suggests that L. grandis is abundant under sandy and gravelly bottoms mixed with shells of the lower sublittoral to subtidal zones during the Quaternary.