Przyczynek do znajomości geochemii strefy wietrzenia krakowskich skał magmowych
Abstract
CONTRIBUTION TO THE KNOWLEDGE OF GEOCHEMISTRY OF WEATHERING ZONE IN THE CRACOW MAGMATIC ROCKS
Summary
The article deals with the results of geochemical investigations made in the region of occurrence of basic type effusive rocks in the vicinity of Cracow. The occurrence area of the Cracow magmatic rocks is an interesting, atypical, geochemical province, characterized by increased contents of main trace elements (Ni, Co, Cr Cu, Pb, Zn and V, partly also Mn), in acid magmatic rocks (porphyries), as well as by slightly decreased contents of these elements in rocks of basic character (melaphyres, diabases). This is connected with an atypical chemical and mineral compositions of these rocks and with their comagmatic character. Weathered products of magmatic rocks of basic type reveal a several times greater concentration of the trace elements (particularly nickel) than fresh rocks. However, a concentration of depositional nature has nowhere been encountered. The Quaternary formations of the region under consideration distinctly show an increased amount of the chemical elements analysed. These, however, do not make any distinct soil anomalies. Methods of geochemical prospection (complexometric method for Ni and spectral method for all the chemical elements analysed) used in the Cracow region allow us to investigate the course of outcrops of basic rocks that occur under a thin Quaternary overburden, and throw light on mineralization degree of both fresh rocks and their weathered products. In connection with other indirect prospecting (e. g. magnetic methods), geochemical investigations may successfully be applied in search for new occurrence sites of magmatic rocks under the Quaternary overburden.
Summary
The article deals with the results of geochemical investigations made in the region of occurrence of basic type effusive rocks in the vicinity of Cracow. The occurrence area of the Cracow magmatic rocks is an interesting, atypical, geochemical province, characterized by increased contents of main trace elements (Ni, Co, Cr Cu, Pb, Zn and V, partly also Mn), in acid magmatic rocks (porphyries), as well as by slightly decreased contents of these elements in rocks of basic character (melaphyres, diabases). This is connected with an atypical chemical and mineral compositions of these rocks and with their comagmatic character. Weathered products of magmatic rocks of basic type reveal a several times greater concentration of the trace elements (particularly nickel) than fresh rocks. However, a concentration of depositional nature has nowhere been encountered. The Quaternary formations of the region under consideration distinctly show an increased amount of the chemical elements analysed. These, however, do not make any distinct soil anomalies. Methods of geochemical prospection (complexometric method for Ni and spectral method for all the chemical elements analysed) used in the Cracow region allow us to investigate the course of outcrops of basic rocks that occur under a thin Quaternary overburden, and throw light on mineralization degree of both fresh rocks and their weathered products. In connection with other indirect prospecting (e. g. magnetic methods), geochemical investigations may successfully be applied in search for new occurrence sites of magmatic rocks under the Quaternary overburden.