Early Cambrian fossil fluorescence and deep time
Glenn A. Brock & Robert A. E. Fosbury
Institute of Advanced Study
University of Durham
This is a summary of a preliminary investigation of the fluorescence spectrum of the primarily calcium phosphate (apatite) biominerals derived from Early Cambrian fossils from the Flinders Ranges in South Australia. In addition to showing the nature of the fluorescence from these ~530 million year old shells, this composite image/plot seeks to illustrate the relationship between deep geological time and astronomical lookback time by showing how much the Universe has expanded since these early bilaterian animals inhabited the Earth's oceans.
The images on the left are scanning electron micrographs of isolated sclerites from two morphospecies of the enigmatic multi-sclerite bearing tommotiid genus Dailyatia (D. macroptera and D. ajax) which are extremely abundant in shallow water carbonates at this time. These scleites are approximately 530 Ma, dated by biostratigraphic correlation to the Cambrian Geological Timescale.
The plots on the right are spectra covering the visible and near infrared wavelengths from 400 - 800nm.
The dark blue spectrum (fossils) is an average of six samples (including phosphatoc brachipods) excited with a 404nm (violet) laser and examined with an Ocean Optics JAZ spectrometer. The lower, light blue plot — shown for comparison — is obtained from a cut blue apatite gemstone with the same illumination and spectrometer.
The thin green line is the spectrum of a galaxy at a redshift of 0.04 from the Sloan Digital Sky Survey (SDSS, www.sdss.org/ ). Using the current cosmological parameters describing the geometry and age of the Universe, this redshift corresponds to a light travel time of 536 million years, meaning that the light from the galaxy image (seen in the upper-mid panel) and spectrum are approximately coeval with the time when these animals were alive on Earth.
The red spectrum (fossils_z) has been 'redshifted' by the factor (1 + z) to represent the effect of the fractional expansion of the Universe from the Early Cambrian to the present time.
The fluorescent emission features in the blue apatite gem and the fossils are due to lanthanide rare earth elements present in small amounts in these calcium phosphate structures. The fossil spectra show an additional broad-band fluorescent component that we have not yet identified.
Early Cambrian fossil fluorescence and deep time
Glenn A. Brock & Robert A. E. Fosbury
Institute of Advanced Study
University of Durham
This is a summary of a preliminary investigation of the fluorescence spectrum of the primarily calcium phosphate (apatite) biominerals derived from Early Cambrian fossils from the Flinders Ranges in South Australia. In addition to showing the nature of the fluorescence from these ~530 million year old shells, this composite image/plot seeks to illustrate the relationship between deep geological time and astronomical lookback time by showing how much the Universe has expanded since these early bilaterian animals inhabited the Earth's oceans.
The images on the left are scanning electron micrographs of isolated sclerites from two morphospecies of the enigmatic multi-sclerite bearing tommotiid genus Dailyatia (D. macroptera and D. ajax) which are extremely abundant in shallow water carbonates at this time. These scleites are approximately 530 Ma, dated by biostratigraphic correlation to the Cambrian Geological Timescale.
The plots on the right are spectra covering the visible and near infrared wavelengths from 400 - 800nm.
The dark blue spectrum (fossils) is an average of six samples (including phosphatoc brachipods) excited with a 404nm (violet) laser and examined with an Ocean Optics JAZ spectrometer. The lower, light blue plot — shown for comparison — is obtained from a cut blue apatite gemstone with the same illumination and spectrometer.
The thin green line is the spectrum of a galaxy at a redshift of 0.04 from the Sloan Digital Sky Survey (SDSS, www.sdss.org/ ). Using the current cosmological parameters describing the geometry and age of the Universe, this redshift corresponds to a light travel time of 536 million years, meaning that the light from the galaxy image (seen in the upper-mid panel) and spectrum are approximately coeval with the time when these animals were alive on Earth.
The red spectrum (fossils_z) has been 'redshifted' by the factor (1 + z) to represent the effect of the fractional expansion of the Universe from the Early Cambrian to the present time.
The fluorescent emission features in the blue apatite gem and the fossils are due to lanthanide rare earth elements present in small amounts in these calcium phosphate structures. The fossil spectra show an additional broad-band fluorescent component that we have not yet identified.