Distribution of phosphorus in the Middle and Upper Ordovician Baltoscandian carbonate palaeobasin

Abstract

Baltoscandian Middle and Upper Ordovician carbonate rocks are relatively poor in phosphorus, with the P2O5 content of 0.05–0.5%, rarely exceeding 1%. Phosphorus distribution in the Ordovician carbonate succession shows spatial and temporal variations. In the Estonian Shelf P content is the highest in the Middle Ordovician, close to the Tremadocian P-rich siliciclastic sediments, decreasing towards younger carbonate rocks. In the basinal, i.e. deep shelf, sections two intervals of elevated P contents occur: the first is similar to the shallow shelf in the lowermost Darriwilian, the second is a moderate P increase in the upper Darriwilian–Sandbian interval. The Darriwilian–Sandbian interval of elevated P content in the deep shelf sections roughly corresponds to algal kukersite accumulations in the shallow shelf. Multiple processes determined phosphorus distribution in the studied sediments. Regional processes influencing P distribution include seawater circulation, e.g. P influx by coastal upwellings, and sedimentation rate. Global oceanic variation in bioproduction (δ13C trends) had no positive effect on P accumulation in the Baltoscandian epeiric sea

Middle Ordovician cephalopod biofacies and palaeoenvironments of Baltoscandia

“…), a time of increased phosphate deposition on Baltica and the greater Iapetus region (Trela ; Kiipli et al . ), an increase in volcanic activity in Avalonia (Botting ), and a dramatic increase in the flux of l ‐chondritic matter to earth (Schmitz et al . ; Cronholm & Schmitz ).…”

“…Possible mechanisms of such a flowering could have been an increased nutrient content of the seawater induced by: (i) a strong transgressive pulse with an associated widespread upwelling or/and (ii) an increased volcanic activity. Peak phosphorous contents are reported from H€ alludden in the beds of approximately AE 0.5 m of horizon D (Sturesson 1986), in Kunda Stage sediments of Estonia (Kiipli et al 2010), and as thick phosphatic coatings on a discontinuity surface that separates sediments of the Lenodus variabilis and the P. serra conodont Zone in the Malopolska Block (Trela 2005). An increased volcanic activity with the Arenig/Llanvirn boundary is documented from the Welsh Basin (Botting 2002).…”

“…Peak phosphorous contents are reported from Hälludden in the beds of approximately ± 0.5 m of horizon D (Sturesson ), in Kunda Stage sediments of Estonia (Kiipli et al . ), and as thick phosphatic coatings on a discontinuity surface that separates sediments of the Lenodus variabilis and the P . serra conodont Zone in the Malopolska Block (Trela ).…”

Internal stratification of two thick Ordovician bentonites of Estonia: deciphering primary magmatic, sedimentary, environmental and diagenetic signatures

“…Increased productivity after the ash-fall, bottom oxygen deficit, enhanced sulphate reduction and raised alkalinity near the sedimentwater interface could possibly favour precipitation of calcium carbonate from the dissolved Ca-hydrocarbonate. The enrichment of P, which is a fundamental limiting nutrient for marine life (Filippelli 2002;E. Kiipli et al 2010), is more controversial.…”

Lower and Middle Ordovician conodonts from the subsurface of SE Estonia and adjacent Russia

“…The Jelgava depression in Latvia came into being in Hunneberg-Billingen time and deepening proceeded up to the end of Kunda time (Männil 1966;Ulst et al 1982). The occurrences of large specimens of some species (Drepanodus and Protopanderodus) in the lower Darriwilian could be explained by upwelling activity (Kiipli et al 2010).…”