Record details

Title
    Geochemistry of host rocks and role of organic matter in the precipitation of cassiterite-sulfide ores at the Dafulou deposit, Dachang tin field (south China)
Statement of responsibility
    Jan Pašava, Bohdan Kříbek
Author
    Kříbek, Bohdan, 1946-
    Pašava, Jan
Language
    anglicky
Source title - serial
    Věstník Českého geologického ústavu (Bulletin of the Czech Geological Survey)
Vol./nr.
    Vol. 76, no. 1
Pages
    p. 3-14
Year
    2001
Notes
    8 obr., 3 fot., 2 tab., 2 s.bibl.
    České resumé
    il.
    Zkr. název ser.: Věst. Čes. geol. Úst. (Bull. Czech geol. Surv.)
Subject group
    hydrotermální alterace
    izotopy
    kasiterit
    kontrola geochemická
    ložisko masivních sulfidů
    ložisko stratiformní
    organická substance
    rudy Sn
    uhlík
    žíla rudní
Geographical name
    Čína jižní
    Dachang (Čína jižní)
    Dafulou (Čína jižní)
Keyword
    Cassiterite-sulfide
    China
    Dachang
    Dafulou
    Deposit
    Field
    Geochemistry
    Host
    Matter
    Ores
    Organic
    Precipitation
    Rocks
    Role
    South
    Tin
Abstract (in english)
   The Dafulou vein and stratabound cassiterite-sulfide deposit is located in the eastern part of the Dachang ore district. The deposit is hosted by a thick sequence of the Lower Devonian calcareous black shales. geochemical study has shown an apparent increase of Sn, As, Bi, Sb, Cu and In from high-calcareous barren black shale through low-calcareous low-mineralized black shale to ore samples. Conversely, values of Sr, Ba, Pb, Zn, V and V/Cr ratio decrease in this order. Significant correlations of Bi and Cu with S and of V and Pb with organic carbon were encourtered. Organic-geochemical study documented that the formation of pyrobitumen, which represents the "distillation product" of the organic alteration at Dafulou, is associated with very strong pyrrhotitization of host rocks and with the formation of massive pyrrhotite ores of the main sulfide stage (Stage II).
   It was suggested that in-situ organic matter locally interacted with hydrothermal solutions which resulted in the decrease in fO2 of the ore solution and subsequencet precipitation of ores. This interaction was evidenced by (1) an enrichment of organic matter (kerogen) in 13C isotope, (2) an increase of its structural organization and, (3) a decrease in the yield of pyrolysable organic matter
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    25. 3. 2008
Import date
    8. 8. 2012