 | | Report (chapter) | | University of Pennsylvania on June 30, 2015 Lake Magadi, Kenya: a model for rift valley hydrochemistry and...H.P. Eugster SUMMARY: Previous studies on Lake Magadi, Kenya, and the Green River Formation of Wyoming...between these two settings, to determine whether Lake Magadi can serve as a reference for rift valley environments...recognizing saline alkaline lake deposits in the geologic column. Magadi inflow waters are influenced...transported during flood events. In contrast, Eocene Lake Gosiute and its mudflats had more gentle gradients |  | | Report (chapter) | | 2015 Tectonics and volcanism of the southern Kenya Rift Valley and its influence on rift sedimentation...SUM M A RY: Volcanism in the northern half of the Kenya Rift Valley began at 30 Ma, and in the southern...graben of the rift floor. In the central sector lake basins spread broadly over pyroclastic deposits...Hypersaline lakes with trona evaporites in the Natron-Magadi basin were caused by the arid climate, eruption...into closed structural basins. Evolution of the Kenya Rift Valley during the last 30 Ma is now moderately |  | | Journal (article/letter/editorial) | | lakes exist on all continents except E urope. Saline lake deposits, however, are usually restricted and ephemeral...the Green River Formation of Wyoming and Searles Lake of California being the exceptions. This neglect...perennial rivers are the Great Salt l,ake of Utah, Lake Chad of Central Africa, the Dead Sea, the Caspian...mud flat; 4. saline mud flat; 5. perennial salt lake; 6. ephemeral salt pan; 7. perennial stream flood...the basin is occupied either by a perennial salt lake of by an ephemeral salt pan. A perennial river is |  | | Report (issue) | | formation of thick and extensive trona and trona-halite beds and accompanying authigenic minerals in the...Paleolimnology of trona deposition________________ Regimen of lake-level changes____________________ Source of components...beds___________________ Concentration owing to decrease of Gosiute Lake volume alone_________________________________ Calculated...atmosphere______ Salinity and composition of Gosiute Lake at salting leveL __ - __ __ ________ __ _____ Mineral...grains--------------------------------------Diagenesis of the lake beds_______________________ Occluded brines ____ |  | | Journal (article/letter/editorial) | | Discussion Eugster and Surdam (1973) proposed a playa-lake model for accumulation of unique deposits of natural...associated genetically with halite, it appears that explanations of the origin of halite deposits must also account...explanation for the origin of salt deposits. Because halite and trona are genetically rela ted, I believe that...Lengai, which is situated on the southern shore of Lake Natron in north Tanganyika. This volcano erupts...volcanic activity. Thus, I cannot agree that the playa-lake model of Eugster and Surdam is correct. REFERENCES |  | Kaufman, Aaron, Margaritz, Mordeckai, Paul, Michael, Hillaire-Marcel, Claude, Hollos, George, Boaretto, Elisabetta, Taieb, Maurice (1990) The 36C1 ages of the brines in the Magadi-Natron basin, East Africa. Geochimica et Cosmochimica Acta, 54 (10) 2827-2833 doi:10.1016/0016-7037(90)90017-f | Journal (article/letter/editorial) | | 2827-2833 in U.S.A. The 36C1 ages of the brines in the Magadi-Natron basin, East Africa AARON KAUFMAN, I MORDECKAI...the East African Rift which includes both Lake Magadi and Lake Natron forms a closed basin within which...consistent with the time of the first appearance of the lake. These older brines also have lower I80 and ‘H values...accumulated brine, together with the known age of the Lake Magadi basin, may be used to estimate the importance...contribute less than 6% of the total 36C1present in the lake. INTRODWXION the basin, and its brines record |  | | Report (issue) | | COLONY AND PROTECTORATE OF KENYA GEOLOGICAL SURVEY OF KENYA OF THE MAGADI AREA DEGREE SHEET 51, S.W...item reference number concerned. GEOLOGY OF THE MAGADI AREA DEGREE SHEET 51, S.W. QUARTER (with two coloured...Sc, F.G.S. Geologist \Ç>5U5 FOREWORD The Magadi soda lake is one of the natural wonders of the world...as a whole. As the rocks of the area, apart from lake beds, consist almost entirely of late Tertiary and...mineral deposits was small. Yet Magadi has provided more mineral wealth for Kenya than any other part of the |  | | Journal (article/letter/editorial) | | and an application to trona deposition in Lake Magadi (Kenya) CHRSTOPHE MONNIN and JACQUE SCHOTT Laboratoire...the major dissolved species in Lake Magadi brines Abstract-The (Kenya). The thermodynamic treatment confirms...of evaporative concentration thermonatrite and halite precipitate. The deposition of the latter salts...intricacies of sodium carbonates deposition in Lake Magadi (Kenya). THE ION INTERACTION MODEL Description In...more concentrated solutions. We also considered halite for which solubilities are Because of the complex |  | | Journal (article/letter/editorial) | | A NEW HYDROUS SODIUM SILICATE MINERAL FROM LAKE MAGADI, KENYA1 Rrcneno A. SunppanD AND Anrrrun J. Guon...three drill holes in the Evaporite Series of Lake Magadi, Kenya. The makatite occurs as white spherulites...(116),2.882(42) (225).The nameis from the Masai(Kenya)word,emakot, which means soda-in allusion to the...investigation of chert in the deposits of Lake Magadi, Kenya. Hay found white acicular crystals intergrown...in drill hole B from the northcentral part of Lake Magadi (Fig. 1). The material gave a distinctive but |  | | Journal (article/letter/editorial) | | S A S S O C I A T E D W I T H T H E S A L I N E LAKE DEPOSITS OF EAST AFRICA * James R. O'NEIL U.S. Geological...44.1. The 6180 values correlate in general with lake salinities as inferred from geologic evidence, indicating...chert was formed from its precursor in contact with lake water trapped at the time of deposition. A few of...O) has been discovered in cores of trona from Lake Magadi [6]. The salinity of the fluid involved in conversion...("natro-carbonatite") lava for comparison with trona of Lake Magadi. The number of analyses is reasonably adequate |  | | Report (chapter) | | the Lake Bogoria basin, Kenya Rift Valley R.W. Renaut, J.J. Tiercelin & R.B. Owen SUMMARY: Lake Bogoria...Bogoria is a perennial, saline, alkaline closed lake fed by hot springs and ephemeral runoff. Detailed studies...both from exposures around the shoreline and from lake bottom cores, have provided abundant evidence for...vivianite. Modern and ancient saline, alkaline lake deposits are well known for their abundant and varied...in the rift valley lake basins of East Africa. Of the East African lakes, Magadi is often regarded as |  | | Journal (article/letter/editorial) | | COMMENT Comment on “The %Clages of the brines in the Magadi-Natron basin, East Africa” by A. Kaufman et al...discussed in relation to chlorinity. INTRODUCMON THE MAGADI-NATRON closed basin in the southern part of the...East Africa is one of the most extensively studied lake systems. The chemical inv~ti~tions of EUGSTER (1970...hydrological model of EUGSTER ( 1970,198O) for Lake Magadi is supported by the environment isotope data...evaluate the age of deep saline brines in the Lake Magadi/Lake Natron basin. These authors derived an age |  | | Journal (article/letter/editorial) | | Phillipsite, Playa lake , Volcanic ash , Zeolites. INTRODUCTION Studies of zeolites in saline-lake environments...Eugster, 1976). Investigations of ancient alkaline lake deposits have established paragenetic sequences...study of modern and ancient environments at Lake Magadi, Kenya, documented several zeolitic reactions and...place in the upper ash bed at Teels Marsh, Mineral County, Nevada (Figure I) . This ash bed generally occurs...Marsh is similar to Lake Magadi in that it is also a modern saline, alkaline-lake environment, and it |  | | Journal (article/letter/editorial) | | source water contrasts with closed-basin saline lake complexes, where surface water from the adjacent...system. The principle geochemical process controlling lake chemistry is evaporative concentration. Other processes...required to be evaporated to produce the observed lake compositions. These differences are related to the...processes? (4) What are the implications of the lake geochemistry relative to the hydrology of the lakes...lakes of the Lake Chad basin, Africa ( EUGSTER and MAGLIONI,1979); and Deep Springs Lake, California (JONES |  | | Journal (article/letter/editorial) | | MINERALOGIST, VOL. 54, JULY_AUGUST, FROM ALKALI 1969 LAKE, OREGON Tnon,rs P. RooNev, U. S. Air Force Combri...associated with alkali saits and brines at Alkali Lake playa, Oregon. Magadiite has apparently precipitated...and kenyaite (NaSirOro,r[(oH)n. 3HrO), from Lake Magadi, Kenya. The magadiite apparently precipitated from...magadiite were observedin playa sediments of Alkali Lake, Oregon, and in muds associatedwith alkali salts...GEoLoGrcSErrrNG Alkali Lake basin is crossedby U. S. Highway 395 in the northeastern part of Lake County, south-central |  | | Journal (article/letter/editorial) | | reactions in the sedimentary deposits of the Lake Magadi region, Kenya RONALD C. SURD AM Department of Geology...M a g a d i basin in the Eastern Rift Valley of Kenya have been investigated. Samples were available f...This gel f o r m s at the lake shore a n d is w a s h e d i n t o the lake d u r i n g flooding conditions...glasses, a n d the brines they come in contact with. Lake M a g a d i represents a u n i q u e o p p o r t...zeolite that will f o r m in a specific alkaline lake e n v i r o n m e n t c a n n o t yet be predicted |  | | Journal (article/letter/editorial) | | Permian paleoclimate data from fluid inclusions in halite Kathleen Counter Benison a a,b,) , Robert H....fluid inclusions in mid Permian Nippewalla Group halite from western Kansas. A ‘cooling nucleation’ method...This study uses fluid inclusion data from Permian halite to construct a record of ancient earth surface...fluid inclusion data from evaporites, especially halite ŽRoedder and Skinner, 1968; Wilcox, 1968; Kovalevich...even moderate heat may alter fluid inclusions in halite. However, possible fluid inclusion alteration can |  | | Journal (article/letter/editorial) | | Printedin Great Britain Brines and evaporites of the Lake Chad basin, Africa HANS P. EUGSTER Department of...continent and on the southern edge of the Sahara, Lake Chad has many peculiar and interesting features...of Tropical Africa, p. 160). A&met-The waters of Lake Chad in Central Africa are dilute and of the Ca-Mg-Na-HCO...with low Cl and S04. In the Kanem region, NE of Lake Chad, such waters are subjected to evaporative concentration...and (cl lakes and plavas located on islands within Lake Chad. The behavior of the major solutes can be interpreted* |  | García-Veigas, Javier, Gündoğan, İbrahim, Helvacı, Cahit, Prats, Eva (2013) A genetic model for Na-carbonate mineral precipitation in the Miocene Beypazarı trona deposit, Ankara province, Turkey. Sedimentary Geology, 294. 315-327 doi:10.1016/j.sedgeo.2013.06.011 | Journal (article/letter/editorial) | | gaylussite. Trona precipitated subaqueously (in lake waters) and as interstitial phase in playa muds...proposed sedimentary model involves an alkaline lake in which water depth fluctuated from deep, perennial...(stratified) stages to shallow, ephemeral, playa lake stages. Lake margin clastic deposits are absent in the...concentrations of extreme organisms. In these settings, lake waters 2− are characterized by relative enrichment...from perennial, meromictic lakes (e.g., Lake Bogoria, Kenya; Renaut and ⁎ Corresponding author. Tel.: |  | | Journal (article/letter/editorial) | | presence of industrial raw material deposits, such as halite and trona, which can not be easily determined by...nahcolite + trona + solution, nahcolite + trona + halite + solution, and trona + thermonatrite + solution...Searles Lake of Pleistocene age in California in the U.S.A. (Eugster & Smith 1965) and Lake Magadi of Pleistocene...salt lakes of Hungary, Egypt and perhaps in Owens Lake, California and Alkali Valley, Oregon. Of course...is precipitated today in the lakes Chad and Magadi in Kenya (Eugster 1970, Eugster et al. 1980). On the |  | | Journal (article/letter/editorial) | | It was first observed by Eugster (1967) at Lake Magadi in the East African rift valley, which is a classic...locations such as Trinity County, California (McAtee et al., 1968), at Alkali-Lake in Oregon (Rooney et al...al., 1969), at Kanem near Lake Chad (Maglione, 1970; Eugster and Maglione, 1979), at alkali lakes in...samples were from Lake Magadi and consisted of well crystalline magadiite and some halite (NaCl). The material...by dissolution of highly-soluble Na salts (e.g. halite or sodium carbonates) or by mixing with Na-rich |  | | Journal (article/letter/editorial) | | Printed inGreatBrltam Hydrochemistry of the Lake Magadi basin, Kenya BLAIR F. JONES U.S. Geological Survey...large number of water samples from the Lake Magadi area, Kenya. These water samples range from dilute...was collected from shallow pits and wells dug into lake sediments and alluvial channels. Saline ground water...major springs. Saturated brines represent surficial lake brines just at the point of saturation with respect...floor north of Lake Magadi, is considered to be the principal recharge to the Magadi ground water system |  | | Journal (article/letter/editorial) | | 1329 Arizona Economic geology Aluminum, Maricopa county, Wickenberg (Sheridan, Michael F , et al.) tt-t2...(Mclean, W. John, er a/.) 7-E 1103 Hemihedrite,Pinal county, Florencemine, Maricopacounty, Wickenburg,Rat Tail...a/.) 7-8 1088 Kinoite, SantaRita mountains,Pima county (Anthony, John W., er a/.) 5-6 7O9 Phoenicochroite...er a/.) 1.2 224 Breccia Intrusive Utah, San Juan county, MosesRock dike, kimberlite (McGetchin, Thomas...(Omori, Keiichi.) tt-12 1897 Wardsmithite,Inyo county, Death Valley, Tertiary, Furnace Creek formation |  | Smith, George I, Friedman, Irving, McLaughlin, Robert J (1987) Studies of Quaternary saline lakes—III. Mineral, chemical, and isotopic evidence of salt solution and crystallization processes in Owens Lake, California, 1969–1971. Geochimica et Cosmochimica Acta, 51 (4) 811-827 doi:10.1016/0016-7037(87)90095-0 | Journal (article/letter/editorial) | | solution and crystallization processes in Owens Lake, California, 1969-1971 GEORGE I. SMITH,’ IRVING...1969-70 flooding of normally dry Owens Lake, a 2.4-m-deep lake formed and 20%of the 2-m-thick salt bed...this depositional process. Deuterium analyses of lake brine, interstitial brine, and hydrated saline phases...Salts first crystallized as floating rafts on the lake surface. Natron and mirabilite, salts whose solubilities...reached their minima; trona, nahcolite, burkeite, and halite, salts with ~lubiliti~ less sensitive to temperature |  | | Journal (article/letter/editorial) | | hot-springs at Bird-Rock, on the east shore of Lake Magadi, Kenya, and at the Gelai magnesite mine, east shore...were collected from the lake crust a~ the bend in the causeway across L. Magadi. The samples, including...;e varying proportions of three main minerals - halite, villiaumite and trona. Analytical methods Fluorine...Bird Rock, Lake Magadi Ge!ai Mine,'Lake Natron East Shore, Lake Magadi East Shore, Lake Magadi Gelai Mine...Mine, Lake Natron Lake Magadi Lake Magadi 3180 4630 2150 758 3720 7700 3950 17.9 16.9 8.22 2.37 3,83 |
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