Discussion of the significance of the flamingo population in Lake Nakuru and other soda lakes in ... more Discussion of the significance of the flamingo population in Lake Nakuru and other soda lakes in the rift valley. It focuses on controls on fluctuating bird numbers as a response to natural fluctuations in lakes hydrochemistry. It underlines how feast and famine condition in this and other salt lakes is the typical situation that defines population numbers in the biota of this and most other schizohaline water bodies, worldwide.
The Red Sea DHAL evaporite-metal-volcanic association underlines why vanished evaporites are sign... more The Red Sea DHAL evaporite-metal-volcanic association underlines why vanished evaporites are significant in the formation of giant and supergiant base metal deposits. Most thick subsurface evaporites in any tectonically-active metalliferous basin tend to flow and ultimately dissolve. Through their ongoing flow, dissolution and alteration, chloride- and sulphate-rich evaporites can create stable brine-interface conditions suitable for metal enrichment and entrapment.
Bedding-parallel fibrous calcite veins crop out at two Permian carbonate localities in the Phetch... more Bedding-parallel fibrous calcite veins crop out at two Permian carbonate localities in the Phetchabun area, central Thailand, within the Nam Duk and Khao Khwang Formations. Samples are studied to determine their petrographic, geochemical and isotopic character, depositional and diagenetic associations and controls on the formation of fibrous calcite across the region. Biomarker and non-biomarker parameters are used to interpret organic matter sources in the vein-hosting units, the depositional environment and levels of source rock maturation in order to evaluate source rock potential in the two Formations. Carbon and oxygen isotope values of the veins and the host are determined to discuss the source of carbonates and diagenetic conditions. The petroleum assessment from the Khao Khwang and Nam Duk Formations suggests that both Formations are a petroleum potential source rock with type II/III kerogen deposited in an estuarine environment or a shallow marine environment and a slope-to...
Ages of exploitable potash deposits range from Quaternary to Devonian; no economic potash deposit... more Ages of exploitable potash deposits range from Quaternary to Devonian; no economic potash deposits are known to occur in Precambrian strata. Most exploited potash is derived from sylvinite ores although carnallitite slurries are processed in the Dead Sea Salt Works. Even though the various potash salts are highly soluble. subsurface solutions cannot alter them until a protective wrap of tight bedded or halokinetic halite has been etched away. Larger economic potash deposits, such as in the Zechstein and Prairie evaporite units, originally precipitated penecontemporaneously as part of the evaporite fill of basinwide settings. This probably reflects the very high salinities that are needed before any brine reaches camallite/sylvite saturation, be it marine, nonmarine or hybrid, The highly isolated conditions that can be attained in "saline giants" tend to favor the accumulation of potash salts in such settings. There is no modem day equivalent to a drawdown basin or saline g...
Interest in the Relief Sandstone as a potential economic oil-bearing sandstone is supported by ex... more Interest in the Relief Sandstone as a potential economic oil-bearing sandstone is supported by excellent reservoir quality (up to 26.6 per cent porosity and 4839 md permeability). Potential source rocks are found above, below and interfingering with the Relief Sandstone. There are several occurrences of live oil bleeding from vugs and fractures in a stratigraphically higher carbonate. Traces of oil in the Relief sands, and the presence of live oil in relatively close proximity, suggests that the Relief Sandstone could host an economic oil accumulation.The majority of the Relief Sandstone was deposited in aeolian or braided fluvial environments with some tidal to shallow marine deposition in the west. Distribution of reservoir-quality sands is bimodal. In the east, porosity and permeability for the most part is very poor to average. In the west, porosity and permeability is generally good to excellent. The bulk of the economic porosity is secondary, a result of dissolution of cement ...
Discussion of the significance of the flamingo population in Lake Nakuru and other soda lakes in ... more Discussion of the significance of the flamingo population in Lake Nakuru and other soda lakes in the rift valley. It focuses on controls on fluctuating bird numbers as a response to natural fluctuations in lakes hydrochemistry. It underlines how feast and famine condition in this and other salt lakes is the typical situation that defines population numbers in the biota of this and most other schizohaline water bodies, worldwide.
The Red Sea DHAL evaporite-metal-volcanic association underlines why vanished evaporites are sign... more The Red Sea DHAL evaporite-metal-volcanic association underlines why vanished evaporites are significant in the formation of giant and supergiant base metal deposits. Most thick subsurface evaporites in any tectonically-active metalliferous basin tend to flow and ultimately dissolve. Through their ongoing flow, dissolution and alteration, chloride- and sulphate-rich evaporites can create stable brine-interface conditions suitable for metal enrichment and entrapment.
Bedding-parallel fibrous calcite veins crop out at two Permian carbonate localities in the Phetch... more Bedding-parallel fibrous calcite veins crop out at two Permian carbonate localities in the Phetchabun area, central Thailand, within the Nam Duk and Khao Khwang Formations. Samples are studied to determine their petrographic, geochemical and isotopic character, depositional and diagenetic associations and controls on the formation of fibrous calcite across the region. Biomarker and non-biomarker parameters are used to interpret organic matter sources in the vein-hosting units, the depositional environment and levels of source rock maturation in order to evaluate source rock potential in the two Formations. Carbon and oxygen isotope values of the veins and the host are determined to discuss the source of carbonates and diagenetic conditions. The petroleum assessment from the Khao Khwang and Nam Duk Formations suggests that both Formations are a petroleum potential source rock with type II/III kerogen deposited in an estuarine environment or a shallow marine environment and a slope-to...
Ages of exploitable potash deposits range from Quaternary to Devonian; no economic potash deposit... more Ages of exploitable potash deposits range from Quaternary to Devonian; no economic potash deposits are known to occur in Precambrian strata. Most exploited potash is derived from sylvinite ores although carnallitite slurries are processed in the Dead Sea Salt Works. Even though the various potash salts are highly soluble. subsurface solutions cannot alter them until a protective wrap of tight bedded or halokinetic halite has been etched away. Larger economic potash deposits, such as in the Zechstein and Prairie evaporite units, originally precipitated penecontemporaneously as part of the evaporite fill of basinwide settings. This probably reflects the very high salinities that are needed before any brine reaches camallite/sylvite saturation, be it marine, nonmarine or hybrid, The highly isolated conditions that can be attained in "saline giants" tend to favor the accumulation of potash salts in such settings. There is no modem day equivalent to a drawdown basin or saline g...
Interest in the Relief Sandstone as a potential economic oil-bearing sandstone is supported by ex... more Interest in the Relief Sandstone as a potential economic oil-bearing sandstone is supported by excellent reservoir quality (up to 26.6 per cent porosity and 4839 md permeability). Potential source rocks are found above, below and interfingering with the Relief Sandstone. There are several occurrences of live oil bleeding from vugs and fractures in a stratigraphically higher carbonate. Traces of oil in the Relief sands, and the presence of live oil in relatively close proximity, suggests that the Relief Sandstone could host an economic oil accumulation.The majority of the Relief Sandstone was deposited in aeolian or braided fluvial environments with some tidal to shallow marine deposition in the west. Distribution of reservoir-quality sands is bimodal. In the east, porosity and permeability for the most part is very poor to average. In the west, porosity and permeability is generally good to excellent. The bulk of the economic porosity is secondary, a result of dissolution of cement ...
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