DSC07972

Texlural Smruty uf

fluzud ifp—u

129

^ 2, iAmtmum and mu*imam ot boifa grem mm mSeee md alnwufl mdmm o# « goiM bar al lnowi B ale

		Mz 10}		9,		W*,
	Bd	14-2,2	0.5->0,7	-01-0,2	14—U	m-m	44>	54
	Bm	1 J — 3.0	04-04	-01-0,1	u—u	Mo-m	41-	4L4
p	Be	2.1-33	04-22	-0.1--05	14—20	•10		10
‘■'V	Bd	-0.5- 1.4	04-2.5	-04-00	OJ-14	700-790	44—
s	Be	-04-1J	07-24	-0.3--Ol	04-2.9	40-MO	20—	40
f $	Be	w	04-14)	-0,1 -0.1	14—14	TiO-MO	U-	io
	(3>		A12 m	AU Aft	et o a	CO CS Cf

0    100    200    300    <O0n»

Fig, 7. Gąbiny site — schcmatic geological sectioa acroaa ihc ctptnurc. Bipianaltom aa in Figurc 4

twofold deposits accumulated over the last millenium. They show either a fiat, parallel lamination or a tabular cross-bedding, and they tend to vary in thickness. The coarser the deposits, the greater are the thicknesses of strata (Fig. 8). Sandy-and-gravelly strata which predominate in the basal part consist of coarse and medium sand. The percentage of gravels decreases upward from 50 in the base to 18 toward the top (Fig. 8). Mz varies from —1.4 to 0.4 0. Sorting improves upward from 2.7 to 1.7. The top senes includes strata composed of medium and fine sands. Grains are fining upward there from Mz = 2.2 0 to Mz = 4.7 0. The above changes are accompanied by changes in sorting from moderate to very poor. Better abraded grains occur in the coarse basal sediments {Wo = 850 — 930). The finer top deposits are charac-terized by the presence of less well abraded grains {Wo = 760—880).

Analysis of the individual profiles in the section discussed indicates that channel shift was accompanied by the elear fining upward of sediments, by their better sorting and by notable changes from negatively skewed deposits to positively skewed deposits. This indicates that depositional conditions of the finer fractions have improved. A characteristic property is the highly variable kurtosis ranging from Iow yalues to exceptionally high values in every profile discussed (Tab. 3). In the section, the inereasing minimum values of kurtosis were associated with channel shift and incision. This may indicate that the river

9 - £volution of the Vistu1a...