| Abstract: | Ironstones recovered from five Late Cretaceous seamounts in the central Pacific region probably formed during late-stage edifice-building volcanism. Ironstones are dense and compact with the appearance of brown chert. The ironstones are characterized by a goethite mineralogy with FeOOH contents up to 88%, extreme fractionation of Fe and Mn, low trace-element and rare earth element abundances, low Co Zn ratios, and isotopic equilibration temperatures of about 20-45 ??C. These characteristics indicate that the ironstones formed from hydrothermal fluids. Ironstones probably formed below the seawater-seafloor interface, as indicated by their occurrence as a proximal hydrothermal deposit, presence of primary goethite cement, pervasive replacement of rocks by goethite, and absence of interbedded pyro-clastic beds. ?? 1994. |
| Genre: | Article |
| ProdID: | 70018013 |
| Citation Author: | Hein, J. R.; Hsueh-Wen, Y.; Gunn, S. H.; Gibbs, A. E.; Chung-ho, W. |
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| Citation End Page: | 189 |
| Citation Issue: | 1 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geochimica et Cosmochimica Acta |
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| Citation Number Of Pages: | 11 |
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| Citation Search Results Text: | Composition and origin of hydrothermal ironstones from central Pacific seamounts; 1994; Article; Journal; Geochimica et Cosmochimica Acta; Hein, J. R.; Hsueh-Wen, Y.; Gunn, S. H.; Gibbs, A. E.; Chung-ho, W. |
| Citation Start Page: | 179 |
| Citation Volume: | 58 |
| Citation Year: | 1994 |
| Type: | citation/reference |
| Text: | Composition and origin of hydrothermal ironstones from central Pacific seamounts; 1994; Article; Journal; Geochimica et Cosmochimica Acta; Hein, J. R.; Hsueh-Wen, Y.; Gunn, S. H.; Gibbs, A. E.; Chung-ho, W. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
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