Metallogeny of the geodynamic systems of the pulsating expanding earth
Yüklə 0,51 Mb. Pdf görüntüsü
|
92 younger epochs of kimberlite magmatism in comparison with more ancient is the increasing thickness of depleted (pyroxene-olivine) pyrolite layer of the mantle (restite). From the pyrolite layer the lithophile elements are taken away, and the formation of kimberlite magma had originated in more deeper horizons of the non-depleted mantle, composed by garnet peridotite and pyroxenite (hypolite), where have been more favorable thermodynamic conditions for crystallization diamonds (Krutoyarskiy at al., 2000). 3. EPOCHS Of FORMATION DEPOSITS OF LITHOPHILIC ELEMENTS AND DIAMONDS The epochs of display the diamond-bearing kimberlites have coincided with the epochs of generation deposits of lithophilic elements, enriched by terra-rare elements and rare metal. All of they are situated on the cratogene platform structures of the Earth and have the age 2500, 1225, 625, 400, 225, 100 Ма (Figure 2, Table 5) (Krutoyarskiy et al., 2000). The extraction of rare metals and alkaline are proceeded by the deeply originated intertelluric fluids from the pyrolite layer of the depleted mantle. These fluids have periodical arisen by the degassing protonic hydrogen from the core of the Earth, which connected to the adequated stage of tectono-magmatic activity. The new stage of the formation terra-rare lithophilic elements in the same block of the earth's crust is possible only in connection with a new stage of expansion of the Earth and the appearance of new volumes of pyrolite, due to disintegration garnet peridotite layers of the non-depleted mantle (Larin, 1980). At the same time in the non- depleted mantle (hypolite) on depths of 170-250 km, arise the " hot points " above the jets of protonic hydrogen and partial melting of the garnet peridotite begins. As the result of this process within the upper mantle an alkaline- ultramafic magmas and displays of diamond-bearing kimberlites and lamproites are being form Table 5. Reserves and resources of lithophile terra-rare elements and diamonds Time (t) 0 25 100 225 400 625 900 1225 1600 2025 2500 3025 3600 (Ma) Geochron. QN PK 2 K 1 JT PCD SOC VR 3 R 2 R 1 PR 2 PR 1 AR 2 AR 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Geodyna- Continental- Platformic- Protooceanic- Permobilic Total mic cycles oceanic geosynclinal protocontinental resources stages Late Mid. Early Late Mid. Early Late Mid. Early Late Mid. Early Diamond (Mc) %% (recovered) 133 1,091 942 704 808 97 1 3,776 3.5 29.0 25.0 19.0 21.0 2.5 0.03 100 Diamond (Mc) %% (resources) 880 2815 2112 1580 1136 265 10 8,798 10.0 32.0 24.0 18.0 13.0 3.0 0.11 100 93 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Tin (Th.t) 464 500 1,297 372 161 153 137 48 24 16 7,086 %% 14.6 15.8 40.9 11.7 5.1 4.8 4.3 1.5 0.7 0.6 100 Tungsten (Th.t) 538 659 1,414 467 38 16 30 10 19 6 3 3,200 %% 16.8 20.8 44.2 14.6 1.2 0.5 0.9 0.3 0.6 0.2 0.1 100 Fluorite (M.t) 31 40 44 120 3 23 39 57 11 8 11 385 %% 8.1 10.4 11.5 31.3 0.6 6.0 10.1 14.8 2.9 2.0 2.9 100 Uranium (Th.t) 200 330 800 385 1 1 255 1375 1175 400 400 5,321 %% 3.7 6.3 15.0 7.2 0.03 0.03 4.8 25.8 22.2 7.5 7.5 100 Niobium (Th.t) 22 2,300 270 1,780 112 4,484 %% 0.5 51.3 6.0 39.7 2.5 100 Tantalum (Th.t) 1,15 8,04 41,31 17,21 22,95 6,89 2,30 6,89 8,03 114.76 %% 1.0 7.0 36.0 15.0 20.0 6.0 2.0 6.0 7.0 100 Beryllium (Th.t) 2,40 2,78 2,59 1,48 3,70 1,30 0,74 1,66 1,85 18.50 %% 13.0 15.0 14.0 8.0 20.0 7.0 4.0 9.0 10.0 100 Lithium (Th.t) 0,29 0,29 0,86 1,14 0,33 1,62 0,81 2,00 2,19 9.54 %% 3.0 3.0 9.0 12.0 3.5 17.0 8.5 21.0 23.0 100 Zircon (Th.t) 10,92 32,74 10,92 10,91 65.49 %% 16.7 50.0 16.7 16.6 100 Rubidium %% 16.5 67.3 6.5 0.7 9.0 100 Strontium %% 1.0 99.0 100 Cesium %% 3.0 4.0 2.5 1.0 36.5 1.0 4.0 48.0 100 Terra-rare Yttrium type %% TR Y 2.0 7.0 91.0 100 Terra-rare Cerium type %% TR Ce 74.0 26.0 100 Yüklə 0,51 Mb. Dostları ilə paylaş:
|