geographia - Studia

L. I. BUZILĂ, O. L. MUNTEAN
S10 6,06 S27 3,40 S43 1,88
S11 37,06 S28 6,33 S44 4,48
S12 25,21 S29 2,78 S45 3,40
S13 30,69 S30 3,45 S46 2,17
S14 0,67 S31 6,25 S47 2,30
S15 28,87 S32 7,54 S50 1,67
S16 19,99 S33 7,90 S51 3,07
S17 2,65 S34 3,14 S52 -
S18 3,30 S35 10,09 S53 6,47
In this case, the alteration intensity was calculated on the base of proportion
between Al and Si oxides. Among the most spread compounds of Earth’s crust, Al and Si
compounds are most stable for normal pH conditions. Information about alteration degree
of weathered deposits is offered by proportion of Al and Si. If this proportion is reduced,
that means a strong alteration of the materials.
4. CONCLUSIONS
The degree, in which the rocks and superficial deposits materials were affected by
weathering, especially by alteration, can be evaluated using two indices, the intensity and
the rate of weathering processes.
The results obtained using the benchmark mineral method shows low and medium
alteration stages of the rocks and weathered materials.
Relative methods allowed the evaluation of the degree of weathering by using
indices that highlight the ratio between stable oxides and those less stable from weathered
deposits. The calculation was made for many samples and the results obtained indicate
again low and medium values of alteration for rocks and weathered materials. These values
characterize mountain areas where the alteration products are continuously evacuated from
the weathering system. Therefore, the occurrence of intense altered deposits is rare, while
low and medium weathered deposits are dominant.
REFERENCES
1. Berindei, I. (1971), MunŃii Bihorului. Morfostructura, în Lucrări ŞtinŃifice, seria Geografie,
Oradea.
2. Bland, W., Rolls, D. (1998), Weathering, an introduction to the scientific principles, Arnold
Publisher, UK.
3. Chittleborough, D.J. (1991), Indices for weathering of soil and paleosols formed on silicate
rocks, Australian Journal of Earth Sciences 38, 115-20.
4. Krauskopf, K.B. (1967), Introduction to geochemistry, McGraw-Hill Publisher, New York.
5. Săndulescu, M. (1984), Geotectonica României, Editura Tehnică, Bucureşti.
6. Smith, B. J., McAlister J. J. (2000), Sampling and pre-treatment strategies for the chemical and
mineralogical analysis of weathered rocks, Zeitschrift fur Geomorphology, N.F., Suppl.-Bd.
120: 159-173, Berlin, Stuttgart.
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