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

Abstract

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.

Experimental Simulation of Evaporation-Driven Silica Sinter Formation and Microbial Silicification in Hot Spring Systems

“…6d), and the formation of molds preserving the morphology of the cells (Fig. 6f), has also been widely described during the formation of silica sinters (Cady and Farmer, 1996;Jones et al, 1998Jones et al, , 2001Jones et al, , 2003Jones et al, , 2005Kyle et al, 2007;Tobler et al, 2008;Parenteau and Cady, 2010). The absence of changes in the size and shape of these molds, despite repeated cycles of desiccation and silica addition, illustrates that dense silica deposits that form as a result of evaporation may be particularly resistant to mechanical deformation, as previously noted by Hinman and Lindstrom (1996) and Orange et al (2013).…”

“…By acting as a reactive substratum for passive and heterogeneous silica nucleation, these microorganisms become very rapidly fossilized and eventually encased in the newly formed sinter (Schultze-Lam et al, 1995;Cady and Farmer, 1996;Renaut et al, 1996;Jones et al, 1997Jones et al, , 1998Jones et al, , 2000Jones et al, , 2001Jones et al, , 2003Jones et al, , 2004Jones et al, , 2008Konhauser et al, 2001;Mountain et al, 2003;Kyle et al, 2007;Tobler et al, 2008). The structure of the microbial communities, as well as their daily or seasonal growth variations, thus also contribute to the development of the fabrics and structure of their entombing sinters (Walter et al, 1976;Hinman and Lindstrom, 1996;Konhauser et al, 2001Konhauser et al, , 2004Jones et al, 2005;Berelson et al, 2011).…”

Origin and significance of lamination in Lower Cretaceous stromatolites and proposal for a quantitative approach

“…Small pyrite crystals observed in the thin micritic crusts of Leza coarse-grained stro matolites (Figs. 7C,9E) are consistent with an origin related with sulphate-reduction, and resemble the small framboidal pyrite crystals that are by-products of sulphate-reduction in present-day microbial mats U0rgensen and Cohen, 1977;Visscher et al, 1998;Popa et al, 2004;jones et al, 2005;Spadafora et al, 2010). Locally, thin micritic crusts show signs of erosion (Fig.…”

Textural and Geochemical Features of Freshwater Microbialites From Laguna Bacalar, Quintana Roo, Mexico

“…However, in Laguna Bacalar, there is minimal sulfate in the lake water. Additionally, the presence of EPS provides nucleation sites for mineral precipitation, while also potentially absorbing essential elements utilized by the cyanobacteria (Pentecost 1978;Pentecost and Riding 1986;Merz-Preifi 2000;Braissant et al 2003;Jones et al 2005;Dupraz et al 2009;Perri and Spadafora 2011;Petrash et al 2011). Collectively, these processes facilitate the formation of the cyanobacterial molds (e.g., Fig.…”