Life is everywhere in sinters: examples from Jurassic hot-spring environments of Argentine Patagonia

Guido, Diego M.; Campbell, Kathleen A.; Foucher, Frédéric; Westall, F.

doi:10.1017/s0016756819000815

Cited by 19 publications

(25 citation statements)

References 35 publications

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“…The fact that other metallic elements (such as Fe, Ti) and trace elements (such as Hg, Tl) have been observed to potentially precipitate on organics in sinters (Guido, Campbell, Foucher, & Westall, 2019;Jones & Renaut, 2007;McKenzie, Brown, Cady, & Campbell, 2001;Trzcinski et al, 2018) further suggests microbial involvement in the enrichment of these elements. Future examination of lithium and rubidium that are closely associated with Cs (Nicholson, 1993) in sinters would be helpful to verify the microbial role in Cs accumulation.…”

Section: Discussionmentioning

confidence: 99%

“…Similarly, microbes are indirectly contributing to the formation of Au‐bearing sinters in the Waiotapu geothermal area in New Zealand (Hedenquist & Henley, 1985), by acting as sites for silica nucleation that incorporates the metallic elements (Jones, Renaut, et al, 2001). The fact that other metallic elements (such as Fe, Ti) and trace elements (such as Hg, Tl) have been observed to potentially precipitate on organics in sinters (Guido, Campbell, Foucher, & Westall, 2019;Jones & Renaut, 2007;McKenzie, Brown, Cady, & Campbell, 2001;Trzcinski et al, 2018) further suggests microbial involvement in the enrichment of these elements. Future examination of lithium and rubidium that are closely associated with Cs (Nicholson, 1993) in sinters would be helpful to verify the microbial role in Cs accumulation.…”

Section: Discussionmentioning

confidence: 99%

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Microbial fabrics of geyserites around hot spring pools in Daggyai, Tibet, China

Jones

et al. 2020

Terra Nova

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The Daggyai geyserites serve as hosts for cesium deposits; however, their origin, whether by chemical deposition or biological formation, is a topic of debate. To decipher the origin of geyserites, the petrographic features of the geyserite samples were examined. The geyserites exhibited columnar laminated, planar laminated and spicular morphologies. Furthermore, they contained morphological and confocal microscopic evidence of the coccoid, bacilliform and filamentous microbes that formed them. Minor calcite and quartz crystals were found locally in the columnar laminated and spicular geyserites. Cyanobacteria tentatively assigned to the genus Calothrix dominated in the planar and columnar laminated geyserites, but were rare in the spicular geyserites. The results demonstrated that the microbes contributed to the Daggyai geyserite formation.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Microbial fabrics of geyserites around hot spring pools in Daggyai, Tibet, China

Jones

et al. 2020

Terra Nova

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“…The encrustation of insects in opal is a rare phenomenon. The few previously documented examples have originated in hydrothermal settings, where silicification rapidly entombs organisms [24][25][26][27]59 . Opal formation through continental weathering is a much more widespread phenomenon, but is also slower.…”

Section: Discussionmentioning

confidence: 99%

“…By contrast, entombment is the trapping of an organism in silica that occurs by a rapid silica precipitation on the external surface. This is mainly documented in hydrothermal settings [24][25][26] , where silica may preserve an entire ecosystem, as observed in the 407-million-year-old Rhynie Chert (Scotland), the oldest fossil terrestrial environment with a comprehensive preservation of flora and fauna 27 . During diagenesis (the hardening of sediments into rocks due to burial), the most amorphous phase of silica (opal-A: amorphous) will transform into more crystalline phases (opal-CT, constituted of nano-domains of cristobalite and tridymite) until it becomes quartz.…”

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Arthropod entombment in weathering-formed opal: new horizons for recording life in rocks

Chauviré

Houadria

Donini

et al. 2020

Sci Rep

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Animal fossils preserved in various geological materials, such as limestone, claystone, or amber, provide detailed information on extinct species that is indispensable for retracing the evolution of terrestrial life. Here, we present the first record of an animal fossil preserved in opal formed by weathering with such high-resolution details that even individual cuticle hairs are observed. the fossil consists of the exoskeleton of a nymphal insect belonging to the order Hemiptera and either the family Tettigarctidae or the Cicadidae. This identification is based on anatomical details such as the tibial and femoral morphology of the forelegs. the exoskeleton of the insect was primarily zeolitized during the alteration of the host rocks and later sealed in opal deposited by silica-rich fluids derived from the continental weathering of the volcanic host rocks. organic matter is preserved in the form of amorphous carbon. This finding makes opal formed by rocks weathering a new, complementary source of animal fossils, offering new prospects for the search for ancient life in the early history of Earth and possibly other terrestrial planets such as Mars, where weathering-formed opal occurs. Most invertebrate fossil records where anatomical details are well preserved are from amber or lacustrine or fluvial sedimentary rocks 1. These fossils have provided evolutionary evidence of ancestral traits and extinct species, retracing the evolution of life. Here, we describe an insect fossil in opal-a variety of silica-in which the degree of preservation is comparable (Fig. 1) 2. Silica minerals exist in various species ranging in structure from amorphous to crystalline. Opal is the main species of amorphous silica that precipitates from saturated or near-saturated silica-rich aqueous fluids produced by the alteration of the earth's crust. One of the main sources of silica for opal formation (and hence the eventual silicification of fossils) are volcanic rocks, especially volcanic ashes due to their inherent porosity and glass abundance 3-8. Among opals, the most sought-after type is precious opal, which differs from common opal only by the presence of colored patches (called play-of-color) that appear to move as the stone is viewed from different angles, an optical phenomenon attributed to the diffraction of visible light by a regular arrangement of silica spheres 9,10. Both precious and common opal form mainly in two geological settings: (1) hydrothermal alteration occurring when hot water circulates underground and precipitates opal when the temperature drops, e.g., as siliceous sinter (a hard incrustation around hot springs); and (2) continental weathering that occurs when meteoric waters percolate, hydrolyzing silicate while transforming the rock into a soil. In both contexts, the dissolved silica exists as silicic acid (H 4 SiO 2) in aqueous solution. Silicic acid will polymerize into silica during a variation in physical or chemical conditions, primarily pH and temperature 11. The degradation of organic matter may favor t...

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“…The Middle-Late Jurassic Bahía Laura Complex in Santa Cruz Province, hosts fossil-rich deposits formed in or at the margins of geothermal systems (Channing et al, 2007;García Massini et al, 2012aGuido & Campbell, 2009, 2019Guido et al, 2010;Sagasti et al, 2016Sagasti et al, , 2018Sagasti et al, , 2020. These are comparable to the famous Devonian Rhynie Chert (e.g.…”

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Plant Taphonomy and Paleoenvironment of the Bahía Laura Complex, Middle–Late Jurassic, at the Laguna Flecha Negra Locality (Santa Cruz Province, Argentina)

et al. 2021

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Taphonomic studies were carried out at Laguna Flecha Negra locality (Bahía Laura Complex, Middle-Late Jurassic), Santa Cruz Province, Argentina. Sedimentary facies and preservational styles were defined to recognize plant taphofacies in the studied sequence. Eleven taphofacies were identified and plant sources within a volcanic and geothermal system are proposed. Plant remains are of autochthonous to para-autochthonous origin and best preservation was found in distal facies of siliceous hot spring (sinter) systems. Lateral and vertical taphonomic differences were found in the studied sequence. These are due to changes in the sedimentary input and distance to the geothermal fluids. Results enable the reconstruction of the depositional history of this region of the Deseado Massif geological Province. We infer formation of a hotspring (sinter) system that was subsequently destroyed by a phreatic eruption process at the margin of an andesitic effusive dome in partially reworked fall pyroclastic subfacies.After the destruction of the geothermal system, a fluvial and lacustrine epiclastic subfacies developed preserving a plant community typical of the Middle-Late Jurassic of Gondwana. Later, volcanic activity produced pyroclastic subfacies, with thick ashfall and flow deposits from different sources and separated by a time gap that promoted fossilization of an in situ forest. Taphonomic studies of these plant communities allowed reconstruction of a chain of geological events and how these processes have influenced the preservation of a Jurassic flora from Patagonia, thus contributing to an understanding of the paleoecology of the Deseado Massif geological province.

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Life is everywhere in sinters: examples from Jurassic hot-spring environments of Argentine Patagonia

Cited by 19 publications

References 35 publications

Microbial fabrics of geyserites around hot spring pools in Daggyai, Tibet, China

Microbial fabrics of geyserites around hot spring pools in Daggyai, Tibet, China

Arthropod entombment in weathering-formed opal: new horizons for recording life in rocks

Plant Taphonomy and Paleoenvironment of the Bahía Laura Complex, Middle–Late Jurassic, at the Laguna Flecha Negra Locality (Santa Cruz Province, Argentina)

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