USGS Professional Paper 1697 - Alaska Resources Library

142 Metallogenesis and Tectonics of the Russian Far East, Alaska, and the Canadian Cordillera
K-Ar isotopic studies indicate intrusive ages of 110 to 115 Ma
for the granitoid rocks hosting the deposits (Rostovsky, 1987;
Stepanov, 1977).
Algama Metallogenic Belt of Stratiform Zr
Deposits (Belt AL), Northern Part of Russian
Southeast
The Algama metallogenic belt of stratiform Zr deposits
(fig. 61; tables 2, 3) occurs to the north of the Kondyor massif
at Algama in the southeastern part of the Stanovoy block
0 M
100
200
300
400
500
x x
x
x
x
x
A x
x
x
B
0 100 200 300 m
A B
v
v
v
of the North Asian Craton (unit NSS; Nokleberg and others,
1997b, 1998). in the western part of the Khabarovsk province
of the Russian Southeast. The deposits are hosted in Vendian
carbonate rock. The belt contains many small occurrences and
a significant deposit at Algaminskoe that has been drilled and
explored by underground workings (Nekrasov and Korzhinsky,
1991). The Algaminskoe deposit consists of hydrozircon
and baddeleyite that occurs with a colloform texture. The ore
occurs in long lenses, conformable to a layer of cavernous
dolomite marble that is as much as about 40 m thick, and in
zones that crosscut metamorphosed Vendian metasedimentary
rocks. The baddeleyite deposits are interpreted as forming
+
+ +
x x
x x x
Turbidite (Late Jurassic)
Limestone (Late Paleozoic)
Conglomerate (Late Paleozoic)
Chert (Late Paleozoic)
Siltstone and sandstone
(Late Paleozoic)
Granite (Early Cretaceous)
Granodiorite (Early
Cretaceous)
Diorite porphyry dike (Early
Cretaceous)
Skarn
Biotite hornfels
Fault
Contact
Figure 64. Vostok-2 W skarn deposit, Luzhkinsky metallogenic
belt, Russian Southeast.Schematic geologic map and cross section.
Adapted from Stepanov (1977). See figure 61 and table 4 for location.