Large-Field Electron Imaging and X-ray Elemental Mapping Unveil the Morphology, Structure, and Fractal Features of a Cretaceous Fossil at the Centimeter Scale
详细信息 查看全文
- 作者：Naiara C. Oliveira ; Jo茫o H. Silva ; Olga A. Barros ; Allysson P. Pinheiro ; William Santana ; Ant么nio A. F. Saraiva ; Odair P. Ferreira ; Paulo T. C. Freire ; Amauri J. Paula
- 刊名：Analytical Chemistry
- 出版年：2015
- 出版时间：October 6, 2015
- 年：2015
- 卷：87
- 期：19
- 页码：10088-10095
- 全文大小：629K
- ISSN：1520-6882
文摘
We used here a scanning electron microscopy approach that detected backscattered electrons (BSEs) and X-rays (from ionization processes) along a large-field (LF) scan, applied on a Cretaceous fossil of a shrimp (area 鈭?80 mm2) from the Araripe Sedimentary Basin. High-definition LF images from BSEs and X-rays were essentially generated by assembling thousands of magnified images that covered the whole area of the fossil, thus unveiling morphological and compositional aspects at length scales from micrometers to centimeters. Morphological features of the shrimp such as pleopods, pereopods, and antennae located at near-surface layers (undetected by photography techniques) were unveiled in detail by LF BSE images and in calcium and phosphorus elemental maps (mineralized as hydroxyapatite). LF elemental maps for zinc and sulfur indicated a rare fossilization event observed for the first time in fossils from the Araripe Sedimentary Basin: the mineralization of zinc sulfide interfacing to hydroxyapatite in the fossil. Finally, a dimensional analysis of the phosphorus map led to an important finding: the existence of a fractal characteristic (D = 1.63) for the hydroxyapatite鈥搈atrix interface, a result of physical-geological events occurring with spatial scale invariance on the specimen, over millions of years.