DENSITY AND LOSS ON IGNITION AS INDICATORS OF THE FOSSILIZATION OF SILICIFIED WOOD

作者：Mustoe George E^*

来源：IAWA Journal, 2016, 37(1): 98-111.

DOI：10.1163/22941932-20160123

• Silicified wood
• petrified wood
• organic matter
• density
• loss on ignition

Measuring density of silicified wood and determining weight loss after 450 degrees C heating provides useful data for interpreting the process of permineralization. These simple gravimetric methods do not replace X-ray diffraction, electron microscopy, polarized light microscopy, Raman spectroscopy, and other specialized techniques for studying fossil wood, but they can be performed rapidly, and require minimal laboratory facilities. Woods mineralized with opal have densities of 1.9-2.1 g/cm(3), compared to 2.3-2.6 g/cm(3) for wood mineralized with chalcedony or quartz. Weight loss after 450 degrees C heating, commonly described as "loss on ignition" can be used to roughly estimate the % of original organic matter that remains in chalcedony or quartz-mineralized wood, using the density of extant taxa for comparison. For opalized wood, 450 degrees C weight loss mostly represents dehydration of the hydrous silica. Data from specimens from 20 localities reveal two characteristics: 1) silicified woods typically consist either of opal or chalcedony/quartz, not an intermediate mixture of the two silica polymorphs; 2) the percentage of organic matter that remains after petrifaction is usually very small.

• 出版日期2016