Carbonate build-ups in lakes, hydrothermal and fluvial settings are characterized by distinctive geometry, spatial distribution, fabrics and geochemical signature but also by some comparable features. Lake margin bioherms form continuous belts for hundreds of metres to kilometres, subparallel to shorelines. Sublacustrine spring mounds are spaced at hundreds of metres to kilometres and aligned along faults. Hydrothermal travertine mounds and aprons with planar clinoforms or terraced slopes are controlled by faults, thermal water discharge and substrate topography. Fluvial tufa barrages, cascades and terraced slopes are controlled by climate, vegetation and substrate gradient. The wide spectrum of carbonate microfabrics ranges from clotted peloidal micrite and laminated boundstone to crystalline dendrite cementstone. Non-marine carbonate microfabrics cannot be linked to specific depositional environments, and are not deterministic proxies for the interpretation of build-up architecture. Microfabric associations can be indicative, but not exclusive, of specific depositional environments and geometry. Stable isotope geochemistry is a useful tool to distinguish between hydrothermal, karstic freshwater and evaporative lake carbonates. Carbonate precipitation results from a continuum of abiotic and biologically influenced/induced processes in settings where carbonate supersaturation is largely driven by physico-chemical mechanisms and microbial biofilms, even if acting as passive low-energy surface sites for nucleation, are widely present.
Carbonate build-ups in lacustrine, hydrothermal and fluvial settings: comparing depositional geometry, fabric types and geochemical signature / G. Della Porta (SPECIAL PUBLICATION - GEOLOGICAL SOCIETY OF LONDON). - In: Microbial carbonates in space and time: implications for global exploration and production / [a cura di] D.W.J. Bosence, K.A. Gibbons, D.P. Le Heron, W.A. Morgan, T. Pritchard, B.A. Vining. - [s.l] : Geological Society of London, 2015. - pp. 17-68 (( convegno Conference on Microbial Carbonates in Space and Time - Implications for Global Exploration and Production tenutosi a London nel 2013 [10.1144/SP418.4].
Carbonate build-ups in lacustrine, hydrothermal and fluvial settings: comparing depositional geometry, fabric types and geochemical signature
G. Della Porta
Primo
Writing – Original Draft Preparation
2015
Abstract
Carbonate build-ups in lakes, hydrothermal and fluvial settings are characterized by distinctive geometry, spatial distribution, fabrics and geochemical signature but also by some comparable features. Lake margin bioherms form continuous belts for hundreds of metres to kilometres, subparallel to shorelines. Sublacustrine spring mounds are spaced at hundreds of metres to kilometres and aligned along faults. Hydrothermal travertine mounds and aprons with planar clinoforms or terraced slopes are controlled by faults, thermal water discharge and substrate topography. Fluvial tufa barrages, cascades and terraced slopes are controlled by climate, vegetation and substrate gradient. The wide spectrum of carbonate microfabrics ranges from clotted peloidal micrite and laminated boundstone to crystalline dendrite cementstone. Non-marine carbonate microfabrics cannot be linked to specific depositional environments, and are not deterministic proxies for the interpretation of build-up architecture. Microfabric associations can be indicative, but not exclusive, of specific depositional environments and geometry. Stable isotope geochemistry is a useful tool to distinguish between hydrothermal, karstic freshwater and evaporative lake carbonates. Carbonate precipitation results from a continuum of abiotic and biologically influenced/induced processes in settings where carbonate supersaturation is largely driven by physico-chemical mechanisms and microbial biofilms, even if acting as passive low-energy surface sites for nucleation, are widely present.File | Dimensione | Formato | |
---|---|---|---|
Della Porta Non marine carbonates submitted July 2014.pdf
accesso riservato
Tipologia:
Pre-print (manoscritto inviato all'editore)
Dimensione
567.73 kB
Formato
Adobe PDF
|
567.73 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.