ALBERT

Description: Area of drilling: Murmanskaya Area, southern part of the South Barents Deep, Barents Sea. Reasons for drilling: 1. Study of the geological structure of the area and obtaining data for stratification of the geological section and its allocation with reflecting seismic horizons; 2. Study of properties, composition and lithologic-facial features of sedimentary rocks. Technical results: The hole has penetrated the section of 1600 m and stopped in Middle Jurassic (Callovian?) deposits. Scientific results: 1. Within the studied geological section a detailed lithologic and stratigraphic sequence of sedimentary rocks (based on microfauna, palynology, and lithologic composition) from Middle Jurassic to Quaternary deposits has been carried out. 2. Thicknesses of the units are as followed: Middle Jurassic (Callovian?) - 40 m, Late Jurassic - 342 m (Oxfordian-Kimmeridgian - 260 m, Tithonian - 82 m), Early Cretaceous - 948 m (Valanginian - 25 m, Barremian-Aptian - 71 m, Aptian - 522 m, Albian - 330 m), Late Cretaceous - 65 m, Neogene-Quaternary - 75 m, Quaternary - 17 m. 3. The section is mostly composed of clayey-silty sedimentary rocks formed in a marine basin. The main part of Mesozoic-Cenozoic deposits formed in a shallow marine basin. 4. Hiatuses in sedimentation during the pre-Cenozoic, the post-Valanginian and the post-Jurassic are assumed. 5. Sharp change of sediment composition occurred in the pre-Cenozoic and the post-Jurassic. 6. In the Late Jurassic the crust of weathering existed in the source area. 7. Sedimentary rocks are weakly lithified (early epigenesis - beginning of late epigenesis). 8. Composition of sedimentary rocks in the hole strongly differs from one of coeval deposits in the Kolguev Island and the Timan-Pechora region.

Description: Area of drilling: Murmanskaya Area, southern part of the South Barents Deep, Barents Sea. Reasons for drilling: 1. Obtaining additional information on the geological section in the Murmanskaya area as well as data for stratification of the section and its allocation with reflecting seismic horizons; 2. Study of properties, composition and lithologic-facial features of sedimentary rocks. Technical results: The hole has penetrated the section of 2930 m and stopped in the Triassic deposits. Scientific results: 1. Comprehensive lithologic and paleontological studies (foraminifera, palynology) of drill samples from the hole have allowed to reveal lithologic features and to carry out a detailed lithologic and stratigraphic sequence of sedimentary rocks from Triassic to Early Cretaceous and from Neogene to Quaternary ones. 2. Thicknesses of the units are as followed: Late Triassic - 869 m, Early Jurassic - 285 m, Middle Jurassic (Aalenian and Bajocian-Bathonian) - 357 m, Late Jurassic - 116 m (Callovian - 63 m, Oxfordian?-Early Tithonian - 30 m, Middle-Late Tithonian - 23 m), Early Cretaceous - 962 m (Valanginian-Hauterivian - 31 m, Barremian-Aptian - 159 m, Aptian - 324 m, Albian - 448 m), Neogene?-Quaternary? - 120 m. Presence or absence of Late Cretaceous and Paleogene deposits (mapped in the South Barents Deep) in the section remains questionable. Presumably these deposits have low thickness and occur above the sampling interval. 3. Clayey-silty sedimentary rocks dominate in the hole. Sandy rocks are of secondary importance. 4. Sedimentation environment has been reconstructed. Middle Triassic to Early Jurassic sediments accumulated in lagoonal and lagoonal-continental conditions. Most part of Middle Jurassic to Quaternary(?) sediments accumulated in a marine mainly shallow basin. Its deepening was in the Late Jurassic. 5. Hiatuses are assumed in the post-Jurassic, post-Valanginian, and pre-Cenozoic time. 6. Composition of sedimentary rocks from the hole strongly differs from one of deposits in the Kolguev Island and the Timan-Pechora region. 7. Sedimentary rocks are weakly lithified (early beginning of late epigenesis).

Description: The hole was drilled in the Severo-Kildinskaya Area in the southern part of the Barents Sea within the South Barents tectonic depression. Reasons for drilling: 1. Specification of the geological structure of the area and obtaining data for stratification of the geological section and its allocation with reflecting seismic horizons. 2. Study of properties, composition and lithologic-facial features of sedimentary rocks. Technical results: The hole has penetrated the section up to 1883 m and stopped in Early Triassic deposits. Scientific results: 1. Within the studied geological section a lithologic and stratigraphic sequence of sedimentary rocks (based on microfauna, spora and pollen spectra, bivalve mollusks, and lithologic composition) from Early Triassic to Quaternary deposits has been carried out. 2. Thicknesses of the units are as followed: Early Triassic - 310 m (Induan - 13 m, Olenekian - 297 m), Middle Triassic - 198 m, Late Triassic - 271 m, Early Jurassic - 152 m, Middle Jurassic - 178 m, Late Jurassic - 96 m, Neocomian - 124 m, Late Cretaceous - 96 m, Cretaceous-Paleogene - 173 m, Quaternary -25 m. 3. Hiatuses are supposed between the Triassic and Jurassic and Early and Late Cretaceous. 4. The Early-Middle Triassic deposits from the section differ from coeval layers in the Kolguev Island and Timan-Pechora region by high increase of gray-colored deposits, toneless series of multicolored deposits, and presence of layers of near-shore marine deposits. 5. The Late Triassic series contains near-shore marine salts. It is intermediate between ones from southern and northern areas of the Barents Sea. It is supposed that that in the Late Triassic during the Early Carnian and Early Norian transgressions the area was in the near-shore marine zone. 6. Silty and clayey deposits dominate in the section. The Early-Middle Jurassic deposits have higher arenosity that is traced regionally. 7. The Middle Jurassic deposits accumulated in marine conditions; deposits from the Kolguev Island - on a continent. In the Upper Jurassic deposits in both areas accumulated in marine conditions.

Description: This report deals with results of the first stage of a complex study of the predominantly Lower Cretaceous sediments cored at Site 398 at depths from 945 to 1740 meters. The section studied is overlain by 35 meters of Cenomanian sediments, which are similar lithologically to the underlying sequence. In the upper part (Unit 3) a major rock-forming carbonate mineral is present in much of the section as calcite, often with distinct structural features indicative of a biogenic origin (nannofossils, skeletal detritus) and diagenetic recrystallization. Unit 3 is characterized by abundant authigenic minerals represented mainly by siderite and manganese-bearing carbonate minerals.