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Geochemistry of formation waters and hydrodynamic evolution of a young and restricted sedimentary basin (Mahakam Delta Basin, Indonesia)
Author(s) -
Furlan S.,
Chaudhuri S.,
Clauer N.,
Sommer F.
Publication year - 1995
Publication title -
basin research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.522
H-Index - 83
eISSN - 1365-2117
pISSN - 0950-091X
DOI - 10.1111/j.1365-2117.1995.tb00091.x
Subject(s) - geology , geochemistry , anticline , sedimentary rock , feldspar , carbonate , structural basin , carbonate minerals , geomorphology , calcite , paleontology , quartz , chemistry , organic chemistry
Chemical and isotopic data on formation waters of oil‐fields from two parallel anticline axes of the Mahakam Delta Basin provide information about the present‐day mass transfers in the sedimentary sequence of this basin. Depletions in Ca, Sr and K, enrichment in Rb, and the Sr/Ca ratios in the waters are related to illitization of smectite and precipitation of carbonate minerals, as well as dissolution of K‐feldspar and precipitation of albite. These short‐lasting processes seem to have been more pronounced in the deeper segments of the proximal anticline. The Sr, oxygen and hydrogen isotopic data emphasize occurrence of lateral migrations of the formation waters within permeable units from Borneo Island to the proximal anticline under continental influence, and further to the distal anticline under marine influence. Description of a combined process including illitization of smectite, precipitation of carbonate minerals, dissolution of K‐feldspar and precipitation of albitic feldspar, during lateral migrations of the formation waters was only possible because of the young age and the restricted volume of the basin. In addition, the chemical signatures in the formation waters were not obscured by water‐rock interactions during long‐distance migrations that occur systematically in large sedimentary basins.