Luis A. Gonzalez R.A. Metzger B.J. Witzke Richard L. Brenner A.P. Murillo T. S. White Greg A. Ludvigson 1998 <div id="15578054" class="article-section-wrapper js-article-section js-content-section " data-section-parent-id="0"><p>Sphaerosiderite, a morphologically distinct millimeter-scale spherulitic siderite (FeCO₃), forms predominantly in wetland soils and sediments, and is common in the geologic record. Ancient sphaerosiderites are found in paleosol horizons within coal-bearing stratigraphic intervals and, like their modern counterparts, are interpreted as having formed in water-saturated environments. Here we report on sphaerosiderites from four different stratigraphic units, each of which has highly variable<span>&nbsp;</span>¹³C and relatively stable<span>&nbsp;</span>¹⁸C compositions. The unique isotopic trends are analogous to well-documented meteoric calcite lines, which we define here as meteoric sphaerosiderite lines. Meteoric sphaerosiderite lines provide a new means of constraining ground-water δ¹⁸O and thus allow evaluation of paleohydrology and paleoclimate in humid continental settings.</p></div> application/pdf 10.1130/0091-7613(1998)026<1039:MSLATU>2.3.CO;2 en Geological Society of America Meteoric sphaerosiderite lines and their use for paleohydrology and paleoclimatology article