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Origin of glauconite in the recent bottom sediments of the ocean
Sedlmentary Geology, 31 (1982) 43--48
43
Elsevier Sclentifm Publishing Company, Amsterdam -- Printed in The Netherlands
ORIGIN OF GLAUCONITE IN THE RECENT BOTTOM SEDIMENTS OF THE OCEAN
N.V. LOGVINENKO
State University, Leningrad (U.S.S.R.) (Accepted for pubhcation May 26, 1981)
ABSTRACT Logvinenko, N.V., 1982. Origin of glauconlte in the Recent bottom sediments of the ocean. Sediment G e o l , 3 1 : 4 3 - - 4 8 There are two general types of sedimentary glauconlte in Recent ocean sediments: terrigenous-allogenic and authigenic glaucomte. Recent sediments of the oceans contain mainly terrigenous-allogenic glauconite (shelf and continental slope) which is formed from ancient glauconite-bearing rocks on coasts, islands and the ocean floor. The age of terrigenous-allogenic glauconite ranges from 2 to 70 m.y. (8 samples from the Atlantic Ocean, 13 from the Paclfm Ocean, 1 from the Indian Ocean). The area of terrigenousallogenic glauconite distr]buhon correlates very well with the area of distribution of glauconite-bearmg rocks on land and does not correlate wlth the climate and bathymetry. Authlgenlc glauconite is seldom found m Recent ocean sediments. The sediments with authlgemc glauconite form transltion zones between sedlments with organic carbon, H2S and sulphide near coasts and oxidized sediments of the ocean floor (red clay and others). The areas of authigenic glauconite distribution are not yet well known. The formahon of authigenlc glaucomte occurs mainly during diagenesis of sediments by synthesis from interstitialsolutions and/or alteration of clay minerals.
INTRODUCTION
The topic to be considered covers some sedimentological and mineralogical problems of the origin of sedimentary glauconite in the Recent b o t t o m sediments of the ocean. The problem of the origin of glauconite has a long history and extensive literature. Glauconite was discovered 150 years ago. We shall not review this but say only t h a t glauconite was t h o u g h t to occur as a diagenetic mineral mainly in shallow-water marine sediments. This point of view is not longer correct, because Recent b o t t o m sediments of the oceans and seas contain mainly terrigenous-allogenic glauconite in shallow-water as well as deepwater sediments. We are now conducting a second r o u n d of investigations of glauconite.
0037-0738/82/0000--0000/$02.75 © 1982 Elsevier Scientific Publishing Company
44 METHODS OF INVESTIGATION The samples of glauconite-bearmg sediments were collected during the expedition of the vessels "Vitjz" and "D. Mendeleev" in the Pacific Ocean (1969--1973). The samples from the Atlantic Ocean were received from R. Kasabov (Murmansk). We t o o k pure glauconite after separating it by size, density and electrical properties. The glaucomte was studied by chemical, optical, X-ray and DTA analysis and its age was determined by K-Ar ratio. This article deals only with sedimentary glauconite. Hydrothermal glauconite was described by Zangahs (1979) and Llpkina {1980) from the basaltic mid-Atlantic ridge and the volcanic rise of the Japan Sea {probably seladonite). SEDIMENTOLOGY Terrlgeneous-allogenlc glauconite is widely distributed m Recent b o t t o m sediments on the shelf (depth from 5--10 to 400--500 m), in terrigenous and carbonaceous sands and silts and on the continental slope (depth from 400-500 to 3000--3500 m) in sands and silts. Glauconite-bearmg sediments have positive Eh, contain organic matter (about 0.5--1.0%) and sometimes contain phosphates. Granulometric curves of the sediments have two or three top (bi- and polymodal)-facies currents and turbidity currents with graded bedding. Terrigene-allogenic glauconite was described by Van Andel (1954), Milliman et al. (1972), Nikolaeva et al. (1977) in the Atlantic Ocean, and Cullen (1967), White (1970), Mac Jlvain et al. {1970), Logvinenko et al. (1975) and many others in the Pacific Ocean. Terrigenous-allogenic glauconite is known in the Indian and Arctic oceans and many seas too. The area of allogenic glaucomte distribution on the sea-floor correlates with the distribution of ancient glauconite-bearing rocks on the land and islands and does not correlate with climate and bathymetry. The age of terrigeneous-allogenic glauconite is from 2 to 70 m.y., see Table I. Authigenic glauconite is seldom found in the Recent b o t t o m sediments of the oceans and seas. Authigenic glauconite is found on the shelf (depth from 5--10 to 5 0 0 - 6 0 0 m) in terrigenous silty clay sands and carbonaceous sediments and on the continental slope (depth from 5 0 0 - 6 0 0 to 3500 m) in terrigenous and terrigeneous
2.7; 2.8', 2 7, 2.5 20.5 1.8 12.2,75,90 19.0 3.0; 5 6 2.1,28.0 0.5; 5.8, 11 0, 13 4 7OO 46.0 0.0
2220 2400 1450 1200 ; 650 ; 1015 600 209,269 250--1500 5--350 800 910--930 59,269
Pacifm Ocean. Near the coast of Honshu Gulf of California Near the coast of Mexico Near the coast of Chile Near the coast of Chile (Antofagasta) Rise of Chathem Atlantic Ocean Shelf of Falkland Island Shelf of SW Africa Near New F o u n d l a n d Near New F o u n d l a n d Indian Ocean Near Hard and Kergelen Islands
Age (m.y.)
Depth (m)
Region
The age of terrigenus-allogenic glauconlte
TABLE I
K r y l o v et a l , 1961
Logvinenko, 1975 L o g v m e n k o , 1975 Logvinenko, 1975 Logvinenko, 1975 Logvinenko, 1975 Cullen, 1967 Nlkolaeva et al., 1975 Nikolaeva et al., 1975 Krylov and Logvlnenko, 1979 Krylov and Logvinenko, 1979
Author (yr.)
46 Authigemc glauconite is forming m the transition zone between the sediments with organic matter, H2S and sulphides of iron near coasts and the oxidized sediments of the ocean floor (red clay and other), but the areas of distribution of authigemc glauconite are not yet well known. MINERALOGY Terrlgenous-aUogemc glauconite is a dl-octahedral hydromma polytype 1M, well crystallized, with small admixture of a mixed-layer mineral montmorillonite- hydromica, which contains 10--20% layers of montmorillomte. The grams of allogemc glauconite have density from 2.6 to 2.9, index of refraction 1.600--1.670, contain 5--6% K20, 20--28% Fe203 and 4--7% A1203. The grains of allogenic glauconite are hard and of a green and blackgreen colour. Authlgenic glauconite is dl-octahedral hydromica polytype 1Md, as a rule badly crystallized and contains mixed-layer minerals montmorillomte-hydromica with 50--70% layers of montmorillonite. Authigenic glauconite contams 2--4% K:O, 10--20% Fe203 and 1--10% AI:O3. Density of authigemc glauconite is from 2.2 to 2.5, index of refraction from 1.570 to 1.600. The grains of authigenic glauconite are soft, often replace pellets and thin layers (about 1--2 mm) and have a light-green and grey-green colour. However, anogemc glauconite may also have these properties (see below). DATA FROM DEEP SEA DRILLING A summary of the composition and dlagenetic alteration of the sediments of the ocean floor was made by Davies and Supko (1973). In Recent deepwater sediments, ocean floor glauconite is absent as a rule or occurs in small quantity (about 1--2%). In shallow-water sediments glauconite was found m the NW Atlantic ocean near the coasts of America and the SE Indian Ocean near the coasts of Australia in Upper Cretaceous to Miocene--Pliocene deposits. CONCLUSION (MODEL OF THE ORIGIN OF SEDIMENTARY GLAUCONITE IN RECENT BOTTOM SEDIMENTS OF THE OCEAN) Recent sediments of the ocean contain mainly allogenic glauconite, whmh is derived from ancient glauconite-bearing rocks on the land, islands and the sea floor. There are two sources of allogenic glauconite in the Recent ocean sediments: ancient glauconite-bearing rocks on the coasts and ocean floor and Recent sediments with authigenic glauconite. AUogenic glauconite is formed as a result of erosion of both types of glauconite by waves, currents and turbidity currents. It consists of grains of ancient glaucomte, ancmnt and recent glauconite or recent glauconite only.
47
The area of distribution of allogenic glauconite is correlated with the area of distribution of ancient glauconite-bearing rocks and n o t with climate and bathymetry. Authigenic glauconite is seldom found in Recent b o t t o m sediments of the oceans. Authigenic glauconite is forming in transition zones between sediments with organic carbon, hydrogen sulphide and sulphides of iron near the coast and oxidized sediments of the ocean floor (red clay and others). Authigenic glauconite occurs due to syntheses from interstitial water solution and/or alteration of clay minerals. The area of distribution of authigenic glauconite are n o t y e t known. ACKNOWLEDGEMENTS
I wish to thank colleagues from the Institutes of Oceanology, Acad. Sci. USSR and Radiology for assisting with this study.
REFERENCES Cullen, D., 1967. The age of glauconite from Chatmam Rise, east of New Zealand. N.Z.J. Mar. Freshwater Res., 1: 399--406. Davies, T. and Supko, P., 1973. Oceamc sediments and their dlagenesis: some examples from deep-sea drilling. J. Sediment. Petrol., 43" 381--390. Gallicher, E.W., 1935. Glauconite genesis. Bull. Geol. Soc. Am., 46: 1351--1366. Krylov, A.Ya., Lisicyn, A.P. and Silln, Ya.I., 1961. Znachenie argon-kalievogo otnoshem]a v okeanlcheskich ilach (The sigmficance Ar-K ratio in oceanic oozes). Izvest. Acad Sci. USSR, Set. Geol., 3 : 8 7 - - 1 0 0 (in Russian). Krylov, A.Ya. and Logvinenko, N.V., 1979. K voprosu ob absolutnom vosraste glauconita v osadcach okeana (To question about absolute age glauconite in the oceanic sediments). Dokl. Acad. Sci. USSR, 249 965--968 (in Russian). Lipk,na, M.I., 1980. Glauconitonosnye porody podvodnych vulkanicheskich got Yaponskogo mor]a (Glaucomte-bear,ng rocks submarine vulkanic mountains Japan Sea). Lithol. Miner Resour (USSR) 4 44--54 (in Russian). Logvmenko, N V., 1975. Absolutnyl vosrast nekotorych glauconitov v sovremennych osadkach Tmhogo okeana (The absolute age some glauconite in Recent sediments of the Pacific ocean). Dokl. Acad. Sci. USSR, 2 2 5 : 6 7 3 - - 6 7 5 (in Russian). Logvmenko, N.V., Volkov, I.I. and Rosanov, A.G., 1975. K voprosu o genesise glauconlta v osadkach T,chogo okeana (To the question about origin glauconite in sediments of the Pacific ocean). Lithol. Miner. Resour. (USSR), 2 : 3 - - 1 5 (in Russian). Mac Ilvalne, J.C. and Ross, D.A., 1973. Surface sediments of the Gulf of Panama. J. Sediment Petrol., 43' 215--223. Milllman, J.D., Pilkey, O.H. and Ross, D.A., 1972. Sediments of the continental Margin of the Eastern United States. Geol. Soc. Am. Bull., 83. N,kolaeva, I V., Plusnin, G.S. and Smirnov, V.N., 1975. Izotopnyl vosrast glaucomta v sovremennych donnych osadkach Mirovogo okeana (The Isotopic age glauconites in Recent bottom sediments of the World ocean). In: Crystallochemm and Paragenesis Minerals of the Sedimentary Rocks. Novosibirsk, Nauka, pp. 28--33 (in Russ,an). Petelin, V P., 1954. O nachojdenii autigennogo glauconita v sovremennych morskich osadkach (About discovery of the authigenic gluaconite in the recent marine sediments). Tr. Inst. Oceanol. Acad. Scl. USSR, 8' 220--227 (in Russian).
48 Takahashl, Y , 1955. Synopsis of glaucomtlzatton In R e c e n t Marine Sediments, a Symposture pp. 503--512. Van Andel, T H., Psotma, H , 1954 R e c e n t sediments of the Gulf of Paria Rep Orinoco shelf expedition. V. 1_ Verh. K. Ned. Akad. Wet. Afd N a t u u r k d reeks 1, B XX, 5 245 pp. White, S.M., 1970. Mineralogy and geochemistry of the continental shelf off the Washington--Oregon Coast. J. S e d i m e n t Petrol., 40' 38--54. Zangahs, K.P. and Harin, G.S., 1979 G l a u c o m t v basaltovol brekchil i m l l o m t a c h iz z o n y rasloma Yan Malen [Norve]sko---Grenlandskn basein] ( G l a u c o m t e f r o m basalt breccia and melanites from zone break Jan Maien [Norwegian---Greenland basra]). G e o c h e m istry, 4 : 6 3 0 - - 6 3 9 (in Russian).
43
Elsevier Sclentifm Publishing Company, Amsterdam -- Printed in The Netherlands
ORIGIN OF GLAUCONITE IN THE RECENT BOTTOM SEDIMENTS OF THE OCEAN
N.V. LOGVINENKO
State University, Leningrad (U.S.S.R.) (Accepted for pubhcation May 26, 1981)
ABSTRACT Logvinenko, N.V., 1982. Origin of glauconlte in the Recent bottom sediments of the ocean. Sediment G e o l , 3 1 : 4 3 - - 4 8 There are two general types of sedimentary glauconlte in Recent ocean sediments: terrigenous-allogenic and authigenic glaucomte. Recent sediments of the oceans contain mainly terrigenous-allogenic glauconite (shelf and continental slope) which is formed from ancient glauconite-bearing rocks on coasts, islands and the ocean floor. The age of terrigenous-allogenic glauconite ranges from 2 to 70 m.y. (8 samples from the Atlantic Ocean, 13 from the Paclfm Ocean, 1 from the Indian Ocean). The area of terrigenousallogenic glauconite distr]buhon correlates very well with the area of distribution of glauconite-bearmg rocks on land and does not correlate wlth the climate and bathymetry. Authlgenlc glauconite is seldom found m Recent ocean sediments. The sediments with authlgemc glauconite form transltion zones between sedlments with organic carbon, H2S and sulphide near coasts and oxidized sediments of the ocean floor (red clay and others). The areas of authigenic glauconite distribution are not yet well known. The formahon of authigenlc glaucomte occurs mainly during diagenesis of sediments by synthesis from interstitialsolutions and/or alteration of clay minerals.
INTRODUCTION
The topic to be considered covers some sedimentological and mineralogical problems of the origin of sedimentary glauconite in the Recent b o t t o m sediments of the ocean. The problem of the origin of glauconite has a long history and extensive literature. Glauconite was discovered 150 years ago. We shall not review this but say only t h a t glauconite was t h o u g h t to occur as a diagenetic mineral mainly in shallow-water marine sediments. This point of view is not longer correct, because Recent b o t t o m sediments of the oceans and seas contain mainly terrigenous-allogenic glauconite in shallow-water as well as deepwater sediments. We are now conducting a second r o u n d of investigations of glauconite.
0037-0738/82/0000--0000/$02.75 © 1982 Elsevier Scientific Publishing Company
44 METHODS OF INVESTIGATION The samples of glauconite-bearmg sediments were collected during the expedition of the vessels "Vitjz" and "D. Mendeleev" in the Pacific Ocean (1969--1973). The samples from the Atlantic Ocean were received from R. Kasabov (Murmansk). We t o o k pure glauconite after separating it by size, density and electrical properties. The glaucomte was studied by chemical, optical, X-ray and DTA analysis and its age was determined by K-Ar ratio. This article deals only with sedimentary glauconite. Hydrothermal glauconite was described by Zangahs (1979) and Llpkina {1980) from the basaltic mid-Atlantic ridge and the volcanic rise of the Japan Sea {probably seladonite). SEDIMENTOLOGY Terrlgeneous-allogenlc glauconite is widely distributed m Recent b o t t o m sediments on the shelf (depth from 5--10 to 400--500 m), in terrigenous and carbonaceous sands and silts and on the continental slope (depth from 400-500 to 3000--3500 m) in sands and silts. Glauconite-bearmg sediments have positive Eh, contain organic matter (about 0.5--1.0%) and sometimes contain phosphates. Granulometric curves of the sediments have two or three top (bi- and polymodal)-facies currents and turbidity currents with graded bedding. Terrigene-allogenic glauconite was described by Van Andel (1954), Milliman et al. (1972), Nikolaeva et al. (1977) in the Atlantic Ocean, and Cullen (1967), White (1970), Mac Jlvain et al. {1970), Logvinenko et al. (1975) and many others in the Pacific Ocean. Terrigenous-allogenic glauconite is known in the Indian and Arctic oceans and many seas too. The area of allogenic glaucomte distribution on the sea-floor correlates with the distribution of ancient glauconite-bearing rocks on the land and islands and does not correlate with climate and bathymetry. The age of terrigeneous-allogenic glauconite is from 2 to 70 m.y., see Table I. Authigenic glauconite is seldom found in the Recent b o t t o m sediments of the oceans and seas. Authigenic glauconite is found on the shelf (depth from 5--10 to 5 0 0 - 6 0 0 m) in terrigenous silty clay sands and carbonaceous sediments and on the continental slope (depth from 5 0 0 - 6 0 0 to 3500 m) in terrigenous and terrigeneous
2.7; 2.8', 2 7, 2.5 20.5 1.8 12.2,75,90 19.0 3.0; 5 6 2.1,28.0 0.5; 5.8, 11 0, 13 4 7OO 46.0 0.0
2220 2400 1450 1200 ; 650 ; 1015 600 209,269 250--1500 5--350 800 910--930 59,269
Pacifm Ocean. Near the coast of Honshu Gulf of California Near the coast of Mexico Near the coast of Chile Near the coast of Chile (Antofagasta) Rise of Chathem Atlantic Ocean Shelf of Falkland Island Shelf of SW Africa Near New F o u n d l a n d Near New F o u n d l a n d Indian Ocean Near Hard and Kergelen Islands
Age (m.y.)
Depth (m)
Region
The age of terrigenus-allogenic glauconlte
TABLE I
K r y l o v et a l , 1961
Logvinenko, 1975 L o g v m e n k o , 1975 Logvinenko, 1975 Logvinenko, 1975 Logvinenko, 1975 Cullen, 1967 Nlkolaeva et al., 1975 Nikolaeva et al., 1975 Krylov and Logvlnenko, 1979 Krylov and Logvinenko, 1979
Author (yr.)
46 Authigemc glauconite is forming m the transition zone between the sediments with organic matter, H2S and sulphides of iron near coasts and the oxidized sediments of the ocean floor (red clay and other), but the areas of distribution of authigemc glauconite are not yet well known. MINERALOGY Terrlgenous-aUogemc glauconite is a dl-octahedral hydromma polytype 1M, well crystallized, with small admixture of a mixed-layer mineral montmorillonite- hydromica, which contains 10--20% layers of montmorillomte. The grams of allogemc glauconite have density from 2.6 to 2.9, index of refraction 1.600--1.670, contain 5--6% K20, 20--28% Fe203 and 4--7% A1203. The grains of allogenic glauconite are hard and of a green and blackgreen colour. Authlgenic glauconite is dl-octahedral hydromica polytype 1Md, as a rule badly crystallized and contains mixed-layer minerals montmorillomte-hydromica with 50--70% layers of montmorillonite. Authigenic glauconite contams 2--4% K:O, 10--20% Fe203 and 1--10% AI:O3. Density of authigemc glauconite is from 2.2 to 2.5, index of refraction from 1.570 to 1.600. The grains of authigenic glauconite are soft, often replace pellets and thin layers (about 1--2 mm) and have a light-green and grey-green colour. However, anogemc glauconite may also have these properties (see below). DATA FROM DEEP SEA DRILLING A summary of the composition and dlagenetic alteration of the sediments of the ocean floor was made by Davies and Supko (1973). In Recent deepwater sediments, ocean floor glauconite is absent as a rule or occurs in small quantity (about 1--2%). In shallow-water sediments glauconite was found m the NW Atlantic ocean near the coasts of America and the SE Indian Ocean near the coasts of Australia in Upper Cretaceous to Miocene--Pliocene deposits. CONCLUSION (MODEL OF THE ORIGIN OF SEDIMENTARY GLAUCONITE IN RECENT BOTTOM SEDIMENTS OF THE OCEAN) Recent sediments of the ocean contain mainly allogenic glauconite, whmh is derived from ancient glauconite-bearing rocks on the land, islands and the sea floor. There are two sources of allogenic glauconite in the Recent ocean sediments: ancient glauconite-bearing rocks on the coasts and ocean floor and Recent sediments with authigenic glauconite. AUogenic glauconite is formed as a result of erosion of both types of glauconite by waves, currents and turbidity currents. It consists of grains of ancient glaucomte, ancmnt and recent glauconite or recent glauconite only.
47
The area of distribution of allogenic glauconite is correlated with the area of distribution of ancient glauconite-bearing rocks and n o t with climate and bathymetry. Authigenic glauconite is seldom found in Recent b o t t o m sediments of the oceans. Authigenic glauconite is forming in transition zones between sediments with organic carbon, hydrogen sulphide and sulphides of iron near the coast and oxidized sediments of the ocean floor (red clay and others). Authigenic glauconite occurs due to syntheses from interstitial water solution and/or alteration of clay minerals. The area of distribution of authigenic glauconite are n o t y e t known. ACKNOWLEDGEMENTS
I wish to thank colleagues from the Institutes of Oceanology, Acad. Sci. USSR and Radiology for assisting with this study.
REFERENCES Cullen, D., 1967. The age of glauconite from Chatmam Rise, east of New Zealand. N.Z.J. Mar. Freshwater Res., 1: 399--406. Davies, T. and Supko, P., 1973. Oceamc sediments and their dlagenesis: some examples from deep-sea drilling. J. Sediment. Petrol., 43" 381--390. Gallicher, E.W., 1935. Glauconite genesis. Bull. Geol. Soc. Am., 46: 1351--1366. Krylov, A.Ya., Lisicyn, A.P. and Silln, Ya.I., 1961. Znachenie argon-kalievogo otnoshem]a v okeanlcheskich ilach (The sigmficance Ar-K ratio in oceanic oozes). Izvest. Acad Sci. USSR, Set. Geol., 3 : 8 7 - - 1 0 0 (in Russian). Krylov, A.Ya. and Logvinenko, N.V., 1979. K voprosu ob absolutnom vosraste glauconita v osadcach okeana (To question about absolute age glauconite in the oceanic sediments). Dokl. Acad. Sci. USSR, 249 965--968 (in Russian). Lipk,na, M.I., 1980. Glauconitonosnye porody podvodnych vulkanicheskich got Yaponskogo mor]a (Glaucomte-bear,ng rocks submarine vulkanic mountains Japan Sea). Lithol. Miner Resour (USSR) 4 44--54 (in Russian). Logvmenko, N V., 1975. Absolutnyl vosrast nekotorych glauconitov v sovremennych osadkach Tmhogo okeana (The absolute age some glauconite in Recent sediments of the Pacific ocean). Dokl. Acad. Sci. USSR, 2 2 5 : 6 7 3 - - 6 7 5 (in Russian). Logvmenko, N.V., Volkov, I.I. and Rosanov, A.G., 1975. K voprosu o genesise glauconlta v osadkach T,chogo okeana (To the question about origin glauconite in sediments of the Pacific ocean). Lithol. Miner. Resour. (USSR), 2 : 3 - - 1 5 (in Russian). Mac Ilvalne, J.C. and Ross, D.A., 1973. Surface sediments of the Gulf of Panama. J. Sediment Petrol., 43' 215--223. Milllman, J.D., Pilkey, O.H. and Ross, D.A., 1972. Sediments of the continental Margin of the Eastern United States. Geol. Soc. Am. Bull., 83. N,kolaeva, I V., Plusnin, G.S. and Smirnov, V.N., 1975. Izotopnyl vosrast glaucomta v sovremennych donnych osadkach Mirovogo okeana (The Isotopic age glauconites in Recent bottom sediments of the World ocean). In: Crystallochemm and Paragenesis Minerals of the Sedimentary Rocks. Novosibirsk, Nauka, pp. 28--33 (in Russ,an). Petelin, V P., 1954. O nachojdenii autigennogo glauconita v sovremennych morskich osadkach (About discovery of the authigenic gluaconite in the recent marine sediments). Tr. Inst. Oceanol. Acad. Scl. USSR, 8' 220--227 (in Russian).
48 Takahashl, Y , 1955. Synopsis of glaucomtlzatton In R e c e n t Marine Sediments, a Symposture pp. 503--512. Van Andel, T H., Psotma, H , 1954 R e c e n t sediments of the Gulf of Paria Rep Orinoco shelf expedition. V. 1_ Verh. K. Ned. Akad. Wet. Afd N a t u u r k d reeks 1, B XX, 5 245 pp. White, S.M., 1970. Mineralogy and geochemistry of the continental shelf off the Washington--Oregon Coast. J. S e d i m e n t Petrol., 40' 38--54. Zangahs, K.P. and Harin, G.S., 1979 G l a u c o m t v basaltovol brekchil i m l l o m t a c h iz z o n y rasloma Yan Malen [Norve]sko---Grenlandskn basein] ( G l a u c o m t e f r o m basalt breccia and melanites from zone break Jan Maien [Norwegian---Greenland basra]). G e o c h e m istry, 4 : 6 3 0 - - 6 3 9 (in Russian).