Perspectives of Kola Alkaline province
The Kola Alkaline Carbonatite Province (KACP), located in the northern Baltic Shield, consists of 20 akaline-ultramafic rock complexes, together with two giant nepheline syenite complexes (Lovozero and Khibiny). Alkaline massifs were formed during short time interval 360-380 Ma (Kramm et al. 1993, Downes et al., 2005). KACP located at the same place with Karelian-Kola paleoproterozoic alkaline province, which include Gremyakha-Vyrmes 1887 ± 58Ma (Sorokhtina et al., 2012) Soustov 1,884±6 Ma Tiksheozero (1999±5), Elet'ozero, and resently finded intrusions Gremikha (1955±11 Ma) Massives El’van’ and Spiridin-Ty, dated as (1668 and 1580 Ma) (Petrovsky et al., 2012). Archean alkaline province include Siilinjarvi (2600 Ma) Sakharyok (2613±35) also exist on the same territory (Zozulja, Bayanova, 2007).
Depth of carbonatite massifs formation was estimated by the microinclusion studies for Turiy Peninsula (1,5±0.5 km) Ozernaya Varaka (2,8±0,7 km), Kovdor (4,0±0,7 km), Vuorijarvi (4,7±0,8 km) and Afrikanda (5,4±0,8 km) (Epstein 1994). Calculated average erosion rate (during last 370 Ma) for this missives vary from 4 m/Ma for Turiy Peninsula to 14.5 Ma for Afrikanda. Pressure estimations by miroinclusions in Lovozero massif and Khibina massif (Kogarko, 1990) allow estimating erosion level as 3 km and 4.4 km, and erosion rate as 8.1 and 11.9 m/Ma respectively. Average erosion rate for Kola Peninsula can be estimated as 10.8 m/Ma (data for Turiy Peninsula, locqated inside Kandalakha graben was excluded).
Similar rate (12.7-13.4 m/Ma) was calculated using thermodynamic estimation of Sakhariok massif formations pressure (9,5-10 kbar) (Kozlovsky, 2001). It show more or less constant upwelling of territory during long time.
Geohpysical data provided by (Arzamastsev et al., 2001) allow estimating depth of the bottom for 18 massifs of KACP. Using this data we can estimate time, which will be necessary for erosion of each massif. It varies from 274 Ma for Africanda to 1443 for Lovozero massif and 1850 for Kovdor. Dependence between number of existing massifs and time may be described by the power law, conform the law of distribution of absolute ages of alkaline rocks and carbonatites around the Word (Zaitsev, 2012).
It we will imagine that some geologist will try to study KACP when it will be the have same age as Karelian-Kola paleoproterozoic alkaline province now, he will find only the rests of Kovdor, and, probably, Lovosero massifs. We can also make another desigion, that when Karelian-Kola paleoproterozoic alkaline province was as yang as Kola Alkaline Carbonatite Province (1,5 By ago) it was much bigger then Kola Alkaline Carbonatite Province now.
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