Isotope geochemistry and origin of illite-smectite and kaolinite from the Seilitz and Kemmlitz kaolin deposits, Saxony, Germany

TY - JOUR

T1 - Isotope geochemistry and origin of illite-smectite and kaolinite from the Seilitz and Kemmlitz kaolin deposits, Saxony, Germany

AU - Gilg, H. A.

AU - Weber, B.

AU - Kasbohm, J.

AU - Frei, R.

PY - 2003/3/1

Y1 - 2003/3/1

N2 - Residual clays that developed on Permian and Carboniferous glass-rich silicic volcanic rocks (pitchstones, ignimbrites) at the Seilitz and Kemmlitz kaolin deposits. Saxony, Eastern Germany, contain locally abundant lath-shaped illite-rich illite-smectite mixed-layer minerals (I-S). Analyses by XRD and TEM-AES reveal a large illite percentage (>∼90%) and R3 ordering in I-S from Seilitz (>∼90%) and smaller illite percentage (∼70%) and R1 ordering in I-S from Kemmlitz. The clays never suffered a deep burial and there is no geological, petrographic or fluid inclusion evidence for acolian input or hydrothermal origin of I-S at either deposit. The I-S formed exclusively at the expense of volcanic glass and not from K-feldspar. Residual quartz phenocrysts in the clays still preserve primary glassy silicate melt inclusions and lack secondary aqueous fluid inclusion trails. The δD and δ18O values of kaolinite and I-S are suggestive of low formation temperatures (<40°C). Rb-Sr and K-Ar dating of I-S-bearing clay separates yield Lower Cretaceous ages at Seilitz and indicates the presence of excess or inherited 40Ar in illite-rich I-S. In contrast, Triassic to Jurassic Rb-Sr ages are obtained for I-S from the Kemmlitz kaolin deposit.

AB - Residual clays that developed on Permian and Carboniferous glass-rich silicic volcanic rocks (pitchstones, ignimbrites) at the Seilitz and Kemmlitz kaolin deposits. Saxony, Eastern Germany, contain locally abundant lath-shaped illite-rich illite-smectite mixed-layer minerals (I-S). Analyses by XRD and TEM-AES reveal a large illite percentage (>∼90%) and R3 ordering in I-S from Seilitz (>∼90%) and smaller illite percentage (∼70%) and R1 ordering in I-S from Kemmlitz. The clays never suffered a deep burial and there is no geological, petrographic or fluid inclusion evidence for acolian input or hydrothermal origin of I-S at either deposit. The I-S formed exclusively at the expense of volcanic glass and not from K-feldspar. Residual quartz phenocrysts in the clays still preserve primary glassy silicate melt inclusions and lack secondary aqueous fluid inclusion trails. The δD and δ18O values of kaolinite and I-S are suggestive of low formation temperatures (<40°C). Rb-Sr and K-Ar dating of I-S-bearing clay separates yield Lower Cretaceous ages at Seilitz and indicates the presence of excess or inherited 40Ar in illite-rich I-S. In contrast, Triassic to Jurassic Rb-Sr ages are obtained for I-S from the Kemmlitz kaolin deposit.

KW - Hydrogen isotope

KW - Illite-smectite

KW - K-Ar

KW - Kaolin deposits

KW - Kaolinite

KW - Kemmlitz

KW - Mesozoic

KW - Oxygen isotopes

KW - Rb-Sr

KW - Saxony

KW - Seilitz

KW - TEM

UR - http://www.scopus.com/inward/record.url?scp=0037364830&partnerID=8YFLogxK

U2 - 10.1180/0009855033810081

DO - 10.1180/0009855033810081

M3 - Journal article

AN - SCOPUS:0037364830

SN - 0009-8558

VL - 38

SP - 95

EP - 112

JO - Clay Minerals

JF - Clay Minerals

IS - 1

ER -