Calcite lilypads and ledges at Lorusio Hot Springs, Kenya Rift Valley: travertine precipitation at the air-water interface

Renaut, Robin W.; Turdu, C. Le

doi:10.1139/cjes-36-4-649

Cited by 5 publications

(8 citation statements)

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“…Ledges and lilypads may unite at the water surface to form a continuous plate of precipitated minerals that will extend outwards until it fractures or sinks under its own weight. Similar morphological forms have since been recognized in modern hot‐spring pools (Renaut et al. , 1999; Campbell et al.…”

Section: Discussionsupporting

confidence: 73%

“…, 1999; Campbell et al. , 2002; Guidry & Chafetz, 2003a), where they are composed mainly of opaline silica and/or calcite, in evaporitic playa lakes where they are composed of salts such as gypsum and halite (Renaut et al. , 1999), and in dilute lakes undergoing freezing that produce lilypads and ledges of ice.…”

Section: Discussionmentioning

confidence: 99%

“…, 1999), and in dilute lakes undergoing freezing that produce lilypads and ledges of ice. Although influenced by microbial processes, including the development of some microbial fabrics, most lilypads described to date have been attributed to abiotic origins with mineral precipitation induced by either physical or chemical processes that take place at or near the air–water interface (Renaut et al. , 1999).…”

Section: Discussionmentioning

confidence: 99%

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Genesis of large siliceous stromatolites at Frying Pan Lake, Waimangu geothermal field, North Island, New Zealand

Jones¹,

Renaut

Konhauser³

2005

Sedimentology

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Lilypad stromatolites, up to 3 m long and 1·5 m wide, were found to be actively growing in the shallow marginal waters of Frying Pan Lake and its outflow channel. These stromatolites, composed of Phormidium (> 90%), Fischerella, and a variety of other microbes, develop through a series of distinct growth stages. Dark green microbial mats cover the floor of the outflow channel and give rise to columns of various sizes and shapes in the shallower marginal waters. Once the columns reach the water level, the mats spread laterally to form a lilypad stromatolite. The lilypads are characterized by a raised, dark green rim, 4–5 mm high, that encircles a flat interior covered with a distinctive orange‐red mat. The microbes forming the columns and lilypad plate are being actively silicified. The stromatolites are formed of: (i) flat‐lying Phormidium filaments (P‐laminae), (ii) upright filaments of Phormidium that are commonly associated with Fischerella (U‐laminae), and (iii) mucus, diatoms and pyrite framboids (M‐laminae). P‐laminae dominate most of the columns, with tripartite cycles of P‐, U‐, to M‐laminae being found mostly in the upper parts of the stromatolites. The transition from the P‐ to U‐laminae is marked by a change in the growth pattern of the Phormidium and branching of Fischerella, which was probably triggered by a change in environmental conditions. In the Frying Pan Lake outflow channel, this change may be related to fluctuations in water level and flow rates that are caused by periods of heavy rain, seasonal changes, long‐term variations in rainfall, and/or the unique 40‐day hydrological cycle that exists between Frying Pan Lake and Inferno Crater, which is a nearby hydrothermal crater lake.

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Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Genesis of large siliceous stromatolites at Frying Pan Lake, Waimangu geothermal field, North Island, New Zealand

Jones¹,

Renaut

Konhauser³

2005

Sedimentology

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“…This surface phenomena lead to the formation of numerous secondary mineral precipitates that may cover the river bed or form a thin crust over the bedrock. The deposit resembles calcium carbonate travertine, which are commonly observed at and around subaerial hot springs in continental rift basins, such as Mammoth Hot Springs in Wyoming [ Ford and Pedley , ; Fouke et al ., ], Bogoria lake in the Kenya Rift Valley [ Renaut and Jones , ; Renaut et al ., ], and volcanic province of central Italy (Viterbo area; Folk []). Travertines constitute a major group of freshwater carbonates, which can be distinguished from one to the other because the origin of the carbon dioxide differs (crustal CO 2 degassing versus atmospheric CO 2 ).…”

Section: Introductionmentioning

confidence: 99%

Mineralogical assemblages forming at hyperalkaline warm springs hosted on ultramafic rocks: A case study of Oman and Ligurian ophiolites

Chavagnac

Ceuleneer

Monnin

et al. 2013

Geochem Geophys Geosyst

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[1] We report on the mineralogical assemblages found in the hyperalkaline springs hosted on Liguria and Oman ophiolites based on exhaustive X-ray diffraction and scanning electron microprobe analyses. In Liguria, hyperalkaline springs produce a thin brownish calcite precipitate that covers the bedrock due to the concomitant atmospheric CO 2 uptake and neutralization of the hyperalkaline waters. No brucite and portlandite minerals are observed. The discharge of alkaline waters in Oman ophiolite forms white-orange precipitates. Calcium carbonate minerals (calcite and/or aragonite) are the most abundant and ubiquitous precipitates and are produced by the same mechanism as in Liguria. This process is observed as a thin surface crust made of rhombohedral calcite. Morphological features of aragonite vary from needle-, bouquet-, dumbbell-, spheroidal-like habitus according to the origin of carbon, temperature, and ionic composition of the hyperalkaline springs, and the biochemical and organic compounds. Brucite is observed both at hyperalkaline springs located at the thrust plane and at the paleo-Moho. The varying mixing proportions between the surface runoff waters and the hyperalkaline ones control brucite precipitation. The layered double hydroxide minerals occur solely in the vicinity of hyperalkaline springs emerging within the bedded gabbros. Finally, the dominant mineralogical associations we found in Oman (Ca-bearing carbonates and brucite) in a serpentinizing environment driven by the meteoric waters are surprisingly the same as those observed at the Lost City hydrothermal site in a totally marine environment.

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“…A systematic understanding of the wide variety of travertine textures has been generated by geochemical and sedimentological research at geothermal sites worldwide (e.g. Kitano 1963;Chafetz & Folk 1984;Folk et al 1985;Farmer & Des Marais 1994;Tazaki 1995;Renaut et al 1999;Fouke et al 2000;Renaut & Jones 2000;Jones et al 2005;Nishikawa et al 2012). However, only a few previous studies have focused on the microbial aspects and effects of travertine deposition (Chafetz & Guidry 1999).…”

Section: Introductionmentioning

confidence: 99%

Textures and processes of laminated travertines formed by unicellular cyanobacteria in Myoken hot spring, southwestern Japan

2013

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Lamina-forming processes of moderately thermophilic (~55°C) unicellular cyanobacteria were identified for the carbonate travertine in the Myoken Hot Spring, Kagoshima Prefecture, southwestern Japan. Continuous 28-h monitoring of surface textures clearly showed a diurnal pattern in sub-millimeter order lamination, comprised of daytime dark colored aragonite layers, and night-time light colored calcite layers. The layering was controlled principally by daily cycles of unicellular cyanobacteria closely related to Thermosynechococcus elongatus BP-1. During a day, cyanobacteria migrated to the surface, and formed a dark green biofilm, in which CaCO 3 is precipitated as radial aggregates of needle aragonite. After sunset, calcite precipitation formed dendritic aggregates of rhombic crystals that cover the biofilm. Physicochemical conditions of the ambient water were stable throughout a day; therefore CaCO 3 polymorphs (aragonite/calcite) were controlled by the presence/absence of certain microbial effects, such as extracellular polymeric substances secreted by cyanobacteria. When travertine growth reached the water level, a yellow-green microbial mat developed on the subaerially exposed surface. Here, filamentous cyanobacteria joined in the microbial community under lowered temperature (~40°C). Aragonite crystal precipitation occurring in the microbial mat supported the microbial effects on CaCO 3 polymorphs. Geomicrobiological processes, effects, and the environmental conditions demonstrated in this travertine provide insights into a further understand of microbial textures in ancient carbonate sediments.

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Calcite lilypads and ledges at Lorusio Hot Springs, Kenya Rift Valley: travertine precipitation at the air-water interface

Cited by 5 publications

References 0 publications

Genesis of large siliceous stromatolites at Frying Pan Lake, Waimangu geothermal field, North Island, New Zealand

Genesis of large siliceous stromatolites at Frying Pan Lake, Waimangu geothermal field, North Island, New Zealand

Mineralogical assemblages forming at hyperalkaline warm springs hosted on ultramafic rocks: A case study of Oman and Ligurian ophiolites

Textures and processes of laminated travertines formed by unicellular cyanobacteria in Myoken hot spring, southwestern Japan

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