Hungarian contribution to the mineralogy and geology of clays

Commemorating the 50th anniversary of the Hungarian Clay Minerals Group founded in 1960

Abstract

The main results of the Hungarian clay research are reviewed in the field of earth sciences in a thematic order.
A general textbook on clay minerals was published by the founder of the Clay Minerals Group, Professor NEMECZ. In a
broader sense, the important books on bauxites by BÁRDOSSY belong to the field of clay research. Soil clay minerals were
discussed in the textbooks of STEFANOVITS, SZENDREI and NEMECZ, and recently by NAGY and KÓNYA.
Specific clay minerals.The famous illite mineral of Füzérradvány — the “second illite in the world” (after the illite of Illinois) — was described by MAEGDEFRAU & HOFMANN as early as 1937 and later reviewed by NEMECZ & VARJÚ.
WEISZBURG and E. TÓTH contributed much to the chemical systematics of celadonite, glauconite and the “Fe-rich
montmorillonite” series. Earlier, serpentine minerals were extensively studied by ERDÉLYI and in recent years by DÓDONY
(structural analyses of antigorite and polygonal serpentine).
Determinative methods in clay mineralogy. A method of quantitative analysis by X-ray diffraction was introduced by
NÁRAY-SZABÓ. A special apparatus for thermal analysis — called the “Derivatograph” —was developed by PAULIK et al.
An atlas of thermal analysis was first compiled by FÖLDVÁRI-VOGL. The application of this method was later continued at a
higher level by FÖLDVÁRI.
Soils and sediments. STEFANOVITS and DOMBÓVÁRI published a map of clay minerals in Hungarian soils. Red clays,
mostly relict fossil soils were studied by BIDLÓ. FEKETE published a book on recent tropical soils. Fossil bentonitic lake
sediments of basaltic craters were recognised by SOLTI and analysed by FÖLDVÁRI, ZS. BARNA and others. KOVÁCS-PÁLFFY
focused his systematic studies on rhyolite-related bentonite deposits of the Carpathian Basin.
Lithostratigraphic applications. Clay minerals of Hungarian sedimentary formations were systematically
characterised by VICZIÁN. Today this line has been continued by RAUCSIK, A. VARGA and SZAKMÁNY. The diagenetic
transformation of smectite to illite was widely applied for CH prospecting by VICZIÁN, J. MÁTYÁS and others. Layer
silicates of the very lowgrade metamorphic stage have been studied by ÁRKAI and his co-workers M. TÓTH, JUDIK etc. He
introduced the parameter “chlorite crystallinity” (Árkai index), studied index minerals, and also applied textural analysis.
His studies extended to Hungary, the Swiss Alps, and to South East Europe.
Zones of hydrothermal alteration in the Tokaj Mts were first recognised by SZÉKY-FUX and later intensively studied by
NEMECZ and VARJÚ and recently by MOLNÁR. Clay deposits of economic value were studied for several decades by E.
MÁTYÁS and ZELENKA, their application and colloidal properties were analysed by JUHÁSZ, SZÁNTÓ and their students.
Model experiments of environmental pollution caused by heavy metals were carried out by NÉMETH. Clay liners for
communal waste depositories were developed by SZABÓ. Pelitic host rocks for high intensity radioactive waste
depositories have been studied in Mecsek Mts.