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Phosphorites
Book Reviews
PhosphorItea edited by Jaques Lucas and Lihane P&v&, Sixth International Field-Workshop and Seminar on Phosphor&, IGCP 156, Morocco-Senegal. Sciences G6ologiques Memoir 77, 1985, 141 p. THISMEMOIR CONTAINSsixteen papers selected from the Sixth
IGCP 156 Meeting, the first of the subgroup on CretaceousTertiary phosphorites. In their introduction, the editors trace the progress in phosphor&e research since the appearance of a state-of-the-art paper three years earlier and conclude that the recognition of the rofe of bacterial activity in phosphogenesis has shown that rni~~n~onrn~~ conditions outweigh the influence of the regional envi~nment and thus has made several earlier problems irrelevant. The memoir opens with a review by A. .I. G. Nothold of the Mediterranean (Tethyan) phosphogenic province; the extended list of references is particularly useful. Five papers deal with aspects of individual phosphorite deposits in Egypt (K. German, W. D. Bock, T. Schroter), Syria (M. Abbes, L. F%%t, J. Lucas), the Kyzilkum area in Soviet Middle Asia (A. L. Yanshin, V. S. Boiko, A. V. Ilyin), the Kaiyang area, China (G. McClellan. M. Coooer. T. Lawendv. M. R. Chen). and the Park W. area in Niger (G. McClelland ‘M.Cooper, T:‘I_awendy, I. Anaaia). The last is important as one of the very rare ~rnb~n~arnb~~ phosphor&s outside the AustraloEastern Asia area. The two preceding papers are interesting, as the deposits they describe are practically unknown in the West. Three papers deal with geochemical aspects of phosphor&s. The first, by Prevot and Lucas, is a statistical treatment of major element abundances in the phosphorites of Ganntour (Morocco). The second, by J. P. Jeanmaire, is an attempt to explain the U-content of the Benguerir phosphorites in Morocco as controlled by three independent processes: primary U-content, weathering losses, and enrichment by leaching from the underlying granite. The third, by A. V. Dar’in and Y. N. Zanin, discusses the distribution of important trace elements in the aluminum-phosphate zones of Christmas Island and
3281
in the Belka deposit (U.S.S.R.), emphasizing the importance of the acidity of the weathering solutions for the trace eiement distribution. Two papers deal with the role of bacteria in phosphorite formation in nature (Y. N. Zanin, S. V. Iatov) and in experiments (J. Lucas, L. P&v&). This is a promising, relatively new line of research which still merits much more study. The two problems which at present dominate research are: 1) The episodicity in which oceanic conditions develop favorably for phosphate deposition. Two papers touch on this question: the one by R. P. Sheldon is highly speculative and invokes the shadow of a tektite ring supposed to have circled the Earth in the Early Tertiary, the other, by P. J. Cook and J. R. Cook, tries to relate the M~ite~~ Phosphate anomaly across the Cretaceous-Tertiary boundary to the rapid biological changes including extinctions which occurred at that time. 2) The second topic, not understood at all, is the mechanism of the huge concentration of phosphorus deposited locally in marine sediments during relatively short time intervals which account for a sizeable proportion of the total P-content of the ocean. This question is not addressed in the volume under review. The two major shortcomings of this selection of papers, devoted essentially to the Mediterranean Phosphor&e province, are: 1) No reference to one of the best documented and most intensively studied group of ph~ho~~~~o~ of Israelis included (except in Nothold’s ~bli~phy), 2) NO study of isotope composition of apatite in phosphorites, the importance of which was already realized at the time of this meeting and which has still increased sin=, is found in these proceedings. Geological Research Division Scripps Institution qf Oceanography (A-012) University of California, San Diego La Jolla, CA 92093, U.S.A.
Y. K. Bentor
PhosphorItea edited by Jaques Lucas and Lihane P&v&, Sixth International Field-Workshop and Seminar on Phosphor&, IGCP 156, Morocco-Senegal. Sciences G6ologiques Memoir 77, 1985, 141 p. THISMEMOIR CONTAINSsixteen papers selected from the Sixth
IGCP 156 Meeting, the first of the subgroup on CretaceousTertiary phosphorites. In their introduction, the editors trace the progress in phosphor&e research since the appearance of a state-of-the-art paper three years earlier and conclude that the recognition of the rofe of bacterial activity in phosphogenesis has shown that rni~~n~onrn~~ conditions outweigh the influence of the regional envi~nment and thus has made several earlier problems irrelevant. The memoir opens with a review by A. .I. G. Nothold of the Mediterranean (Tethyan) phosphogenic province; the extended list of references is particularly useful. Five papers deal with aspects of individual phosphorite deposits in Egypt (K. German, W. D. Bock, T. Schroter), Syria (M. Abbes, L. F%%t, J. Lucas), the Kyzilkum area in Soviet Middle Asia (A. L. Yanshin, V. S. Boiko, A. V. Ilyin), the Kaiyang area, China (G. McClellan. M. Coooer. T. Lawendv. M. R. Chen). and the Park W. area in Niger (G. McClelland ‘M.Cooper, T:‘I_awendy, I. Anaaia). The last is important as one of the very rare ~rnb~n~arnb~~ phosphor&s outside the AustraloEastern Asia area. The two preceding papers are interesting, as the deposits they describe are practically unknown in the West. Three papers deal with geochemical aspects of phosphor&s. The first, by Prevot and Lucas, is a statistical treatment of major element abundances in the phosphorites of Ganntour (Morocco). The second, by J. P. Jeanmaire, is an attempt to explain the U-content of the Benguerir phosphorites in Morocco as controlled by three independent processes: primary U-content, weathering losses, and enrichment by leaching from the underlying granite. The third, by A. V. Dar’in and Y. N. Zanin, discusses the distribution of important trace elements in the aluminum-phosphate zones of Christmas Island and
3281
in the Belka deposit (U.S.S.R.), emphasizing the importance of the acidity of the weathering solutions for the trace eiement distribution. Two papers deal with the role of bacteria in phosphorite formation in nature (Y. N. Zanin, S. V. Iatov) and in experiments (J. Lucas, L. P&v&). This is a promising, relatively new line of research which still merits much more study. The two problems which at present dominate research are: 1) The episodicity in which oceanic conditions develop favorably for phosphate deposition. Two papers touch on this question: the one by R. P. Sheldon is highly speculative and invokes the shadow of a tektite ring supposed to have circled the Earth in the Early Tertiary, the other, by P. J. Cook and J. R. Cook, tries to relate the M~ite~~ Phosphate anomaly across the Cretaceous-Tertiary boundary to the rapid biological changes including extinctions which occurred at that time. 2) The second topic, not understood at all, is the mechanism of the huge concentration of phosphorus deposited locally in marine sediments during relatively short time intervals which account for a sizeable proportion of the total P-content of the ocean. This question is not addressed in the volume under review. The two major shortcomings of this selection of papers, devoted essentially to the Mediterranean Phosphor&e province, are: 1) No reference to one of the best documented and most intensively studied group of ph~ho~~~~o~ of Israelis included (except in Nothold’s ~bli~phy), 2) NO study of isotope composition of apatite in phosphorites, the importance of which was already realized at the time of this meeting and which has still increased sin=, is found in these proceedings. Geological Research Division Scripps Institution qf Oceanography (A-012) University of California, San Diego La Jolla, CA 92093, U.S.A.
Y. K. Bentor