Mineral resources in Lower Brule Indian Reservation

On the Lower Brule Indian Reservation in South Dakota, about 3 million tons of metallic manganese are in low-grade deposits in the DeGrey Member of the Pierre Shale on the reservation. The geology and methods of mining and processing this sub-economic mineral resource have been studied extensively; technologically, extraction of manganese is possible. However, an efficient, economical method to separate manganese-bearing nodules from the shale host rocks has yet to be found. The manganiferous nodules occur in the Oacoma zone of the Sully shale member (De-Grey Member) which is a subdivision of the South Dakota Pierre Shale formation. These nodular deposits have an interesting similarity in stratigraphical position, lithology and manganese content to those of the Porcupine Mountain area in Manitoba.

(Table 1) Cation exchange capacity and other characteristics of soils common in Lower Saxony, Germany

The chemical and biochemical processes associated with the filtration of rainwater through soils, a step in groundwater recharge, were investigated. Under simulated climatic conditions in the laboratory, undisturbed soil columns of partly loamy sands, sandy soils and loess were run as lysimeters. A series of extraction procedures was carried out to determine solid matter in unaltered rock materials and in soil horizons. Drainage water and moisture movement in the columns were analysed and traced respectively. The behaviour of soluble humic substance was investigated by percolation and suspension experiments. The development of seepage-water in the unsaturated zone is closely associated with the soil genetic processes. Determining autonomous chemical and physical parameters are mineral composition and grain size distribution in the original unconsolidated host rock and prevailing climatic conditions. They influence biological activity and transport of solids, dissolved matter and gases in the unsaturated zone. Humic substances, either as amorphous solid matter or as soluble humic acids play a part in diverse sorption, solution and precipitation processes.

Carbonate content in lower Cretaceous sediments of ODP Hole 123-765C

Sediments recovered during Ocean Drilling Program (ODP) Leg 123 from the Argo Abyssal Plain (AAP) consist largely of turbidites derived from the adjacent Australian continental margin. The oldest abundant turbidites are Valanginian-Aptian in age and have a mixed (smarl) composition; they contain subequal amounts of calcareous and siliceous biogenic components, as well as clay and lesser quartz. Most are thin-bedded, fine sand- to mud-sized, and best described by Stow and Piper's model (1984) for fine-grained biogenic turbidites. Thicker (to 3 m), coarser-grained (medium-to-coarse sand-sized) turbidites fit Bouma's model (1962) for sandy turbidites; these generally are base-cut-out (BCDE, BDE) sequences, with B-division parallel lamination as the dominant structure. Parallel laminae most commonly concentrate quartz and/or calcispheres vs. lithic clasts or clay, but distinctive millimeter- to centimeter-thick, radiolarian-rich laminae occur in both fine- and coarse-grained Valanginian-Hauterivian turbidites. AAP turbidites were derived from relatively deep parts of the continental margin (outer shelf, slope, or rise) that lay below the photic zone, but above the calcite compensation depth (CCD). Biogenic components are largely pelagic (calcispheres, foraminifers, radiolarians, nannofossils); lesser benthic foraminifers are characteristic of deep-water (abyssal to bathyal) environments. Abundant nonbiogenic components are mostly clay and clay clasts; smectite is the dominant clay species, and indicates a volcanogenic provenance, most likely the Triassic-Jurassic volcanic suite exposed along the northern Exmouth Plateau. Lower Cretaceous smarl turbidites were generated during eustatic lowstands and may have reached the abyssal plain via Swan Canyon, a submarine canyon thought to have formed during the Late Jurassic. In contrast to younger AAP turbidites, however, Lower Cretaceous turbidites are relatively fine-grained and do not contain notably older reworked fossils. Early in its history, the northwest Australian margin provided mainly contemporaneous slope sediment to the AAP; marginal basins adjacent to the continent trapped most terrigenous detritus, and pronounced canyon incisement did not occur until Late Cretaceous and, especially, Cenozoic time.

Benthic foraminifera in Lower Cretaceous sediments from various DSDP samples

From the DSDP Legs 1, 11, 13, 17, 25, 27, 32, 36, 41, 43, 44, 50, and 62 the Lower Cretaceous foraminifers have been investigated for biostratigraphical, taxonomical, and palaeoecological purposes. An overview of the cored Lower Cretaceous sections of Leg 1-80 is given. In the Northern Atlantic Ocean characteristic foraminiferal faunas are missing from the Upper Tithonian to the Valanginian due to a marked regression which caused hiatuses. In areas without black shale conditions Valanginian to Barremian medium rich to poor microfaunas with Praedorothia ouachensis (Sigal) of the Praedorothia ouachensis Zone (Valanginian-Hauterivian). The Hauterivian-Aptian interval is characterized by zones of Gavelinella barrerniana, Gaudryina dividens, and Conorotalites aptiensis. During the Albian a world-wide fauna consisting of agglutinated and calcareous foraminifers of the Pseudoclavulina gaultina Zone is established in areas lacking the wide-spread black-shale conditions. The Upper Albian and the Cenomanian are represented by the Gavelinella eenomanica Zone. Some ornamented species of the nodosariids (Citharina, Lenticulina), Gavelinella, Conorotatites, Pleurostomella, Vatvulineria, and Osangularia are of some importance for the biostratigraphy of the Berriasian-Albian interval. The Berriasian to Albian zones introduced for the Tethys and the DSDP by Moullade (1984) could only be of some local importance due to the long stratigraphical range of the foraminiferal species used. In the Indian Ocean an exact stratigraphical age cannot be assigned to the few Neocomian foraminiferal faunas of a cooler sea water (Site 261). These faunas mainly contain primitive agglutinated foraminifers, because in most cases the calcareous tests are dissolved or redeposited. In the Pacific Ocean most of the Berriasian to Aptian microfaunas are of minor biostratigraphical and palaeoecological importance for reasons of poor core recoveries, contaminations or original foraminiferal poverty (black shales). Since the Albian there are somewhat higher-diverse faunas of calcareous and agglutinated foraminifers with index species of the Pseudoclavulina gaultina Zone. As a rule, the boundary Albian/Cenomanian is set by means of planktonic foraminifers because no other foraminifer has its first appearance datum during this interval, except Gavelinella cenornanica. During the Albian very uniform, world-wide foraminiferal faunas without a marked provincialism are obvious.