The Perseverance rover (Mars 2020) is equipped with an instrumental and analytical payload capable of identifying a broad range of organic molecules in geological samples. To determine the efficacy of these analytical techniques in recognizing important ecological and environmental signals in the rock record, this study utilized analogous equipment, including gas chromatography/mass spectrometry, Raman spectroscopy, X-ray fluorescence (XRF), Fourier transform infrared spectroscopy, along with macroscopic and petrographic observations, to examine early-middle Cambrian microbialites from the Arrowie Basin, South Australia. Morphological and petrographic observations of these carbonate successions reveal evidence of hypersaline-restricted environments. Microbialites have undergone moderate diagenesis, as supported by XRF data that show mineral assemblages, including celestine and the illitization of smectite. Raman spectral data, carbon preference indices of ∼1, and the methylphenanthrene index place the samples in the prehnite/pumpellyite metamorphic facies. Pristane and phytane are the only biomarkers that were detected in the least thermally mature samples. This research demonstrates a multitechnique approach that can yield significant geological, depositional, paleobiological, and diagenetic information that has important implications for planning future astrobiological exploration.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1089/ast.2019.2110 | DOI Listing |
Geobiology
March 2021
Instituto de Geociências, Universidade de Brasília, Brasília, Brazil.
In east-central Brazil, the Ediacaran-Cambrian Bambuí Basin has the potential to provide a record of unique geochemical responses of Earth's ocean and atmosphere evolution during this key time interval. From this perspective, we studied an interval of the upper Bambuí Basin using sedimentologic, stratigraphic, and chemostratigraphic tools. The lower Cambrian Jaíba Member of the uppermost Serra da Saudade Formation is an interval of up to 60 m-thick of carbonate rocks disposed into two shallowing upward trends.
View Article and Find Full Text PDFAstrobiology
May 2020
Department of Biological Sciences, Macquarie University, Sydney, Australia.
The Perseverance rover (Mars 2020) is equipped with an instrumental and analytical payload capable of identifying a broad range of organic molecules in geological samples. To determine the efficacy of these analytical techniques in recognizing important ecological and environmental signals in the rock record, this study utilized analogous equipment, including gas chromatography/mass spectrometry, Raman spectroscopy, X-ray fluorescence (XRF), Fourier transform infrared spectroscopy, along with macroscopic and petrographic observations, to examine early-middle Cambrian microbialites from the Arrowie Basin, South Australia. Morphological and petrographic observations of these carbonate successions reveal evidence of hypersaline-restricted environments.
View Article and Find Full Text PDFPLoS One
December 2019
School of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan, China.
Epiphyton, Renalcis, and Girvanella are ubiquitous genera of calcified cyanobacteria/algae from Early Paleozoic shallow-marine limestones. One genus, Epiphyton, is characterized by a particular dendritic outline, and extensive research has revealed the morphology of calcified remains although little information on cellular structure is known. The mass occurrence of calcified Epiphyton in microbialites from Cambrian Miaolingian, the Mianchi area of North China is preserved as black clots within thrombolites and have dendritic and spherical outlines when viewed with a petrographic microscope.
View Article and Find Full Text PDFOecologia
October 2016
DST/NRF Research Chair in Shallow Water Ecosystems, Nelson Mandela Metropolitan University, Port Elizabeth, 6031, South Africa.
Microbialites, bioaccretionary structures formed during the growth and metabolism of microorganisms (principally cyanobacteria) were the dominant lifeform in shallow late-Archean and Proterozoic oceans. During the Cambrian radiation of metazoan life, which began ~540 Mya, microbialite abundance and diversity further declined following a peak in the Mesoproterozoic. Notwithstanding contention, grazing and bioturbation effects of metazoans have been hypothesized as the dominant driver of modern microbialite scarcity.
View Article and Find Full Text PDFGeobiology
March 2015
Grant Institute, School of GeoSciences, University of Edinburgh, Edinburgh, UK.
We describe new, ecologically complex reef types from the Ediacaran Nama Group, Namibia, dated at ~548 million years ago (Ma), where the earliest known skeletal metazoans, Cloudina riemkeae and Namacalathus, formed extensive reefs up to 20 m in height and width. C. riemkeae formed densely aggregating assemblages associated with microbialite and thrombolite, each from 30 to 100 mm high, which successively colonised former generations to create stacked laminar or columnar reef frameworks.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!