Własności sorpcyjne osadów z dna Basenu Gdańskiego w rdzeniu M-37/13404-1

Abstract

Określono ilościowy udział jonów Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe³⁺ i Zn²⁺ adsorbowanych powierzchniowo oraz w kompleksie sorpcyjnym osadów z rdzenia z dna Basenu Gdańskiego. Na podstawie modelu genetycznego Vu Ngoc-Ky i in. (1981) rozpoziomowano osady pod względem środowiska sedymentacyjnego. Wyniki zestawiono z fazami rozwojowymi Bałtyku. Stwierdzono, że osady górnej części rdzenia do 625 cm tworzyły się w środowisku morskim o zmiennym zasoleniu (morze litorynowe). Na głębokości 625 - 655 cm występują osady lagunowe wysłodzone (jezioro ancylusowe), na głębokości 655 - 965 cm osady morskie (morze yoldiowe) i od 965 cm do spągu osady lagunowe wysłodzone (bałtyckie jezioro lodowe).

SORPTION PROPERTIES OF SEDlMENTS FROM CORE M-37/13404-I, SEA-FLOOR IN THE GDAŃSK EMBAYMENT

The paper present results of studies on sorption properties of sediments from the core M-37/13404-1, coming from western part of the Gdańsk Embayment. Sorption of ions Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe³⁺ and Zn²⁺ was determined by the ammonium chloride method and that of the exchangeable ion H₃O^- - by the barium chloride method. The sorption complex appears markedly varying in composition, evidencing changes in sedimentary environment. Types of sedimentary environment corresponding to sediments displayed by the core were reconstructed using the selected genetic model. Sediments forming upper part of the core down to the depth of 625 cm were round to be characterized by typically marine composition of sorption complex. Moreover, this interval displays cyclic variability in sorption capacity, related to changes in salinity of the reservoir due to successive inflows of oceanic water.

Sediments from depth interval 625 - 655 cm are characterized by increase in share of calcium ions and high value of the coefficient K⁺/K⁺ + Na⁺ so they may be treated as freshened lagoonal.

Composition of sorption complex of sediments from the next interval (655 - 965 cm) corresponds to sediments of marine reservoir with normal or somewhat increased salinity.

At depth over 965 cm, share of calcium ions in sorption complex increases. sorption of ions Na⁺ and Mg²⁺ markedly decreases, and the coefficient K⁺/K⁺ + Na⁺ is high, indicating fresh-water character of the relevant sediments.

The above discussed types of sedimentary environments were subsequently compared with subdivision of the core section according to development phases of the Baltic, established on the basis of lithological and palynological data.