Sedimentary: Phosphates☆

Dar, Shamim A.; Khan, K. F.; Birch, W.D.

doi:10.1016/b978-0-12-409548-9.10509-3

Cited by 14 publications

(9 citation statements)

References 46 publications

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“…This event was correlated to the Global Curriculum Current which has been reported previously by Refs. [1,5,29] and others. In this particular period, surface and deep-water paleotemperature progressively declined [22].…”

Section: Early Campanian Neo-tethys Oceanmentioning

confidence: 99%

“…Scientists have tried for a long time to understand the genesis of phosphates, but they struggled with the fact that phosphates can be found in divergent oceanic settings; some are found in the open marine system, e.g. [2], others are found in the infratidal to circatidal environments [3] and there is also phosphate deposition in estuaries and semi-restricted embayments [4,5]. These vast occurrences of phosphates make reaching a consensus on one model that explains the occurrences of phosphatic layers impossible.…”

Section: Introductionmentioning

confidence: 99%

“…Phosphorite deposits in the ocean are associated primarily with the productivity of surface water that has been detected during the Late Cretaceous period in the southern Neo-Tethys [1,2,5,7]. Primary productivity is considered particularly in upwelling areas, where phosphate is released from the degradation of organic matter in the deep ocean.…”

Section: Introductionmentioning

confidence: 99%

“…Primary productivity is considered particularly in upwelling areas, where phosphate is released from the degradation of organic matter in the deep ocean. Upwelling current brought phosphorous and other nutrients to coastal areas and enhanced the primary productivity of these components in the water column [1,5].…”

Section: Introductionmentioning

confidence: 99%

“…Phosphate formation requires suboxic and sometimes anoxic alkaline conditions. This can be in restricted basins or in the oxygen minimum zones, where organic matter degraded to produce phosphorus ions directly or from iron oxides [3,4,5,8,10,11].…”

Section: Introductionmentioning

confidence: 99%

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Paleoenvironmental Study of the Late Cretaceous–Eocene Tethyan Sea Associated with Phosphorite Deposits in Jordan

et al. 2023

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Petrological, geochemical, and biostratigraphical investigations have been conducted on seventy-nine samples from four selected sections in Jordan to understand the factors that influenced the enrichment and deposition of massive phosphorite deposits. The calcareous nannofossil marker species Broisonia parca constrica and Reticulofenestra bisecta, from the assigned sections 1 and 2 (Hawar and Al Dhahikiyya), were indicative of the Campanian and Eocene periods, respectively. The enrichment of some ecological marker species such as Kamptnerius magnificus indicates that there were cold periods during phosphate precipitation. All thin sections of the phosphate samples are of grainstone and packstone textures and are composed of skeletal fragments and peloids. Skeletal fragments appeared to be the main component of Hawar phosphates with the existence of peloids, while peloids were the component in sections 2 and 3 (section 3: Al Hisa). At least three intervals of high phosphorous values appeared in the Hawar section, showing variations in the Ca and Nd isotopes and in the terrigenous inputs. Four periods of phosphate enrichment are observed in Section 2 and Section 3. These are deep water circulation periods of the early and late Campanian period, interrupted by two periods of submarine and continental weathering. Deep water circulation was initiated during cooling in the Campanian period and indicated by high phosphorous and Ca isotope components and a decline in terrigenous indicators (Al, Si, Ti, and Fe). Submarine weathering during warmer deep-sea periods is indicated by a rising Nd isotope ratio when many of the igneous provinces were subjected to weathering. Continental weathering took place in the warmer periods, with the hydrologic cycle and enhancement of terrigenous indicators (Al, Si, Ti, and Fe) being observed. The effect of the hydrologic cycle was at its highest in the south during the Campanian period and in the Eocene, as both represented shallower settings.

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