A Móra Ferenc Múzeum Évkönyve, 1971. 1. (Szeged, 1971)

Molnár, Béla–Mucsi, Mihály–Magyar, László: Latest quaternary history of the southern stretch of the Tisza valley

Table 1. Examples of the results of the analysis for heavy minerals and grain shape of sand sampler from the borholes in the Lake Dongér area (Fraction anlized: (0,1—0,2 m/m) Name of mineral No of borehole and interval of sampling Sands of mixed, Danube-Tisza, origin Sands of Tisza origin 0,6—0,9 m 15. 0,5—0,85 m 13. 1,9—2,0 m 18. 7,0—7,35 m 14. 8,5—9,0 m 6,7 5,1 1,3 Hypersthene 6,7 5,1 1,3 11,8 18,7 Other ortho-rhombic pyroxenes 1,8 2,8 3,1 1,1 1,3 Augite 10,9 11,3 8,8 | 24,0 | |19,3| Diopside 1 3,0 | 0,6 Í 2,3 | 0,6 | 2,5 | 1,3 1,1 0,7 Bazaltic hornblende 1 3,0 | 0,6 Í 2,3 | 0,6 | 2,5 | 1,3 9,7 \ 14,7 Magnetite 4,2 3,0 5,6 0,6 5,0 1,9 7,0 12,0 Biotite 4,2 3,0 5,6 0,6 5,0 1,9 2,7 1,3 Apatite 0,6 3,1 1,1 1,3 Zirkon — 0,6 — — •— Chlorite 0,6 1,1 0,6 2,2 3,3 Turmaline 1,8 — 3,1 1,6 — Zoisite — — 0,6 0,7 Rutile — — 0,6 0,5 — Hornblende 4,2 3,4 10,7 5,4 3,3 Actinolite-tremolite 2,4 — 1,9 0,5 — Garnet 29,8 41,8 37,2 9,7 12,7 Staurolite 1,2 1,7 1,3 0,5 — Kyanite 0,6 1,1 — 0,5 2,0 Calcite-dolomite — — — 2,2 0,7 Limonite 1,8 1,1 1,3 2,7 — Weathered minerals 26,8 20,9 15,7 15,7 6,7 Total heavy minerals weight % of the analyzed fraction 3,46 2,8 2,35 2,32 2,02 Grain shape analyses 1. — — — 0,8 2,5 ( % of grain types) 2. 32 ' 65 | 28 30,5 1 68,0 1 57,6 | | 41,2 61,0

1 3. 32 ' 65 | 70 ! 30,5 1 68,0 1 57,6 | | 41,2 36,0 4. 3 2 1,5 0,4 0,5 grains of Carex, Typha and Sagittaria and of Botryococcus algae, forms indicating a stagnant-water environment (flood-plain), were encountered. According to Mrs. Miháltz, the above pollen assemblage is indicative of a humid climatic phase tending to coolness. This is confirmed by the presence of peaty lenses. On account of their physical conditions of occurrence and pollen spectrum, these strata may have been deposited during the W

2

—W

3 interstadial which preceded the last glaciation. The overlying loess contains few pollen grains : mainly Pinus silvestris. This loess layer was deposited in the last stadial: in W

3

. The slightly peaty lenses with fossil plant remains occurring in its lower part may correspond to the transition from the W

2

—W

3 interstadial to the W

3 stadial, i. e. to an enviromment which may have been temporarily warmer and wetter. 9