Origin of glauconite in the recent bottom sediments of the ocean

There are two general types of sedimentary glauconite in Recent ocean sediments: terrigenous-allogenic and authigenic glauconite. 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 Pacific Ocean, 1 from the Indian Ocean). The area of terrigenous-allogenic glauconite distribution correlates very well with the area of distribution of glauconite-bearing rocks on land and does not correlate with the climate and bathymetry.Authigenic glauconite is seldom found in Recent ocean sediments. The sediments with authigenic glauconite form transition zones between sediments 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 formation of authigenic glauconite occurs mainly during diagenesis of sediments by synthesis from interstitial solutions and/or alteration of clay minerals.