K R Y ST Y N A K O N E C K A -B E T L E Y
DEVELOPMENT OF THE SOIL-FORMING PROCESSES OF LATE PLEISTOCENE AND HOLOCENE IN DUNES
OF THE ENVIRONS OF WARSAW
D ep artm en t of S o il S cien ce, A g ricu ltu ra l U n iv e r sity at W arsaw
IN TR O DU C TIO N
One of the stratigrap h y elements of dunes of Middle P oland are fossile soils. They are characterized, first of all, by the accum ulation of organic m atter w ith different thickness and decomposition degree as well as by the occurence of deeper diagnostical horizons depending on m aterial and soil-forming process advance.
The degree of soil-form ing processes in the intradune fossile soils depends on climate, lithology, vegetation and time and to an insignificant degree on the activity of m an of those times. Therefore, these soils, preserved as fossil stages, are of great im portance for the reconstruction of n atu ra l environm ent of the late Pleistocene and Holocene, as w ell as for determ ination of stronger or w eaker stability of ecosystems of those times. On their basis also the sequence of soil-forming processes on sandy m aterial after recession of the last cool period can be reconstructed.
On the basis of earlier investigations (9, 10, 11, 2] and of results of physico-chemical analyses and investigations a t use of radiocarbon from the site of intradune fossile soils at Cięciwa, most representable for the environs of W arsaw, the events in late Pleistocene and Holocene concerning the course of soil-forming precesses and development of various soil types are presented in the paper.
ST R A T IG R A P H Y OF D U N E S
Dunes in the W arsaw valley occupy wide areas. Their origin is connected w ith late Pleistocene : the oldest, older and younger Dryas.
K o b e n d z i n a [6, 7, 8] is of the opinion th a t the m ain stabilization
of inland dunes by vegetation occurred in the Alleröd interstadial, whe reas later dune-form ing stages did not play already such im portant role.
R ó ż y c k i [1 2] distinguishes still on this area, m ainly around the
Błonie plain, dunes older than D ryas ones, occuring in the form of long dykes the origin of which, according to this author, could being in the polar desert prior to encroachm ent of the continental glacier of the Baltic glaciation.
The oldest dunes [12] occur in the area of the lie terrace by Otwock, then after the Poznań glaciphase the lib terrace by P raga or Falenica develops, on which new dunes are forming. Ju st these dunes enter the m argin betw een the lib and lie terraces, destroy it and then cross the area of the upper accum ulation terrace and enter the upland. In the Vistula valley, at the Pom eranian interstadial the accum ulation of lower p a rt of the Praga terrace of Ila occurs.
B a r a n i e c k a [1] distinguishes three or even four generations of dunes, connected w ith p articular terraces.
While assuming the concept of Różycki concerning origin and age of terraces and taking into consideration different studies on dunes of the W arsaw valley, the view can be p u t forw ard th a t on terraces of different age the developm ent of dunes of the late Pleistocene oc curred at the same time. Namely, soils of the same age developed in dunes formed both on the Otwock terrace and on the youngest — but ncn-floded — Praga terrace, w hat was confirmed by the organic substance
form ation dates, determ ined at use of 14C [13, 14, 9, 11, 2].
Dunes of the W arsaw environs began to develop as one of the areas of M iddle-Polish dunes [5, 16] in the oldest Dryas period, under condi tions of subarctic climate, w ith the m ean tem perature of Ju ly below 10°C. At the first stage of this period woodless tu n d ra predominates, at the second — single trees and sea buckthorn clumps appear. The dune- forming activity on the m ineral m aterial m anifests itself by the occur rence of small flat dune forms, of 2-3 m in height, and sometimes of light muds.
Warming up of the climate a t the Bölling interstadial, w ith the m ean tem perature of Ju ly reached ± 15° С (m oderately cool climate) led to a cessation of dune-form ing activity and an encroachm ent of birch forests w ith large sea buckthorn clumps. The above period lasted about 300 years.
In the middle Dryas a wave of the repeated coolness came — the m ean tem perature of July dropped down to 10-12°C. Dry subarctic climate led to disappearance of forests and to encroachm ent of the tu nd ra w ith single trees and m uch narrow er areas covered by sea buckthorn clumps. Dune- forming processes occurred anew, leading to the form ation of middle Dryas dunes. These dunes reach the height of 10-15 m and even 20-30 m [7]. Over the rem aining dunes, along w ith the repeated w arm ing up of the climate w ith the tem perature of Ju ly of 16° С in the Alleröd in ter stadial, encroaches vegetation : birch and birch-pine forests in the first
phase, dry pine forests — in the second. In the second phase of the Alleröd interstadial a narrow ing of the area occupied by sea buckthorn clumps takes place. In this period dunes were fully stabilized by pine forests, and under such conditions the form er were, probably, able to make stand to the dune-form ing action of the youngest Dryas.
Form ation of dunes in the youngest Dryas under conditions of sub arctic climate w ith the mean tem perature of Ju ly of 12°C, led to a reduction of forest areas and to a w ater level drop in lakes. At th a t time park tu nd ra and steppe communities predominate. Intensification of the dune-form ing activity in th a t period was not too strong as compa red w ith the middle Dryas. Dunes reached, namely, at th a t time the height of 3-5 m only. The dune-form ing activity vanishes at the end of the youngest Dryas.
In the youngest Dryas the period of the late Pleistocene came to an end, as since the pre-B oreal period Holocene began already. In the pre-Boreal period new ly-form ed dunes were stabilized by vegetation, the area of pine forests widened under conditions of m oderate climate w ith the m ean tem perature of Ju ly of 13-14°C. The encroachm ent of pine forest communities and then the appearance of plants w ith higher climatic demands took place throughout the Boreal period and the whole A tlantic period. In the clim atically optimum Holocene, i.e. in the Atlanticum , according to S r o d o ń [15], mixed forest prevailed. However, the encroachm ent of the m ixed or deciduous forest vegetation over dunes was lim ited by a low content of nutrien ts in dune sand. Palynological investigations of B o r ó w k o - D ł u ż a k o w a [4] confirm the p re sum ption th a t in the clim atically optim um Holocene forest communities at predominance of pine and birch occurred as well and m ixed forests
covered in total 2 0°/o of the area.
The fu rth er periods of Holocene — sub-Boreal and sub-A tlantic ones, were characterized by cooler climate and a reduction of forest areas in consequence of the intensifying hum an activity. It led to the form ation of anthropogenic dunes and to the destruction of older, w ell-form ed soils.
C H A R A C T E R IST IC S OF F O S S IL SO IL S OF THE C IĘCIW A SITE
Fossil soils of the Cięciwa site developed in the priod of late Pleisto cene and also in Holocene, and were closely connected w ith the stra ti graphy of dunes of this area. Their form ation ran in the period of w ar ming up of the climate in the Alleröd interstadial and in all Holocene periods. It is to stress th a t in the profile of Cięciwa no presence of soil from the Bolling interstadial on m ineral form ations has been found. The palynological investigations of the W arsaw environs resulted record
In the profile in question, representable for the W arsaw environs, on the middle Dryas dune an older w eakly formed, podzolized fossil soil, originating probably from the Alleröd interstadial, has been found. Weakly m arked A t horizon of this soil contains a certain am ount of charcoal. Initial A 2 and В horizons occur in a discontinous layer. A characteristic feature of the whole, and p articularly of the С horizon, is the occurrence of ferruginous fibres of an irregular shape. Their form ation is connected w ith a variable granulom etric composition of particular thin dune layers and w ith variable redox potential. This soil usually pinches out upw ards, w hat proves a stronger inclination of slope of the older Dryas dune. By the radiocarbon m ethod the age of organic m etter from this soil was determ in ed ; it am ounted to 11150± 1300 years of BP (Lod 30).
In the same profile, lower at the foot of the dune, the soil from the Alleröd interstadial occurs as a weakly developed formation, gleyed or as a soil complex consisting of several less thick hum us horizons, w hat proves local blowing away of the dune m aterial. The granulo m etric composition of this soil proves a predominance of the fraction of m edium -grained sand and the m ineral composition of the heavy fraction — a relatively low w eathering degree of the sandy m aterial.
The composition of various forms of hum us compounds of weakly formed soil from the Alleröd interstadial proves its weak podzolization in view of a considerable percentage of humic acids of free and bounded fraction as compared w ith fulvic acids. Of th a t the H : F ratio am ounting to about 1.6 can bear evidence. A characteristic feature of this soil is its low pH value am ounting to about 4.
Soils of the Alleröd interstadial, developed on soils of the middle Dryas, were covered in the youngest Dryas by a series of dunes and were blown down in certain geomorphological situations. On dunes of the youngest Dryas soil-form ing processes began as early as in pre- Boreal and lasted unin terru pted ly till the end of the A tlanticum , forming eventually the ferruginous-hum ous podzol or hum us podzol. In other situations, on dunes of the youngest Dryas, on the tu rn of pre-B oreal and Boreal, rust-coloured soil w ith a w ell-m arked B r horizon of an intensive w eathering in cooler climate were formed. It was characterized by lacking or weakly m arked A x horizon, which probably underw ent destruction. This soil, not always w ell-form ed a t different geomorpho logical stages, was sometimes covered by a not too thick layer of sand coming from local blowings, on which ferruginous-hum ous podzol developed.
It follows from the above th a t the form ation of this soil can be lim ited to the final stage of Boreal and to the A tlanticum end. The wholeness of morphological features and physico-chemical properties of the soil proves its long-term podzolization process.
A particularly characteristic feature of this soil is the occurrence of strongly m arked illuvial horizon, divided into B H and BlS subhorizons, and an often occurrence of a shallow mucked peat in the ceiling. The BH horizon’s age was estim ated by means of 14C for 7150 ±150 years of BP (Lod 47) and of the shallow m uck layer in the ceiling for 6155 ±270 BP (Lod 31).
The morphologic stru ctu re and physico-chemical properties of fossil ferruginous-hum ous podzol as well as the datings by means of 14C prove a long-term soil form ation period under variable microclimatic condi tions. At the first podzolization stage, under conditions of periodical anaerobiosis in upper horizon of this soil, m ainly readily soluble compo unds of fulvic acids w ith free iron and alum inium forms, in which iron Fe2+ and Al3+ are inside the organic molecule, not affecting the change of negative charge of these compounds, are forming. The compounds m entioned are very mobile and translocate in the anion form into the B H horizon, in which they p artly precipitate in consequence of tran s gression of the isoelectric point for iron and alum inium and undergo a slightly m arked biodégradation. Beside the above characteristic com pounds, also hum ous-ferruginous compounds in the cation form develop, in which iron occurs in trivalen t form. These compounds precipitate more readily in the BH horizon. Sim ultaneously fulvic acids in the illuvial horizon can be transform ed into humic acids, b u t under certain condi tions hardly-soluble hum us compounds, so-called humines, can be formed. A t the same time Fe and A1 hydroxides were formed, w hich not only contributed to precipitation of readily soluble hum us-m ineral com pounds, b u t also exerted a stabilizing effect on humines.
In consequence of the long-term podzolization, compact iron pan layers form ed in the illuvial horizon of this soil w ithout any action of ground waters. In the iron pan humus, iron, alum inium and silica form stable compounds. W ithin the fram ew ork of the above soil-forming process the B H and Bs subhorizons were form ed in the illuvial horizon, and in the subhorizon B s free silica and free alum inium played a basic role.
The cem entation of illuvial horizons by sesquioxides is connected w ith hum id climate and plays higher role in coarse-grained m aterial (as it was the case at Cięciwa).
Iron pan forms occurring in the B n and B s subhorizons of A tlantic podzols as well as the presence of compounds not only of iron, but also of alum inium w ith humus, prove a leaching character of iron pan formation.
The hypothesis cocerning form ation of podzols in the climatis optimum of the A tlanticum was confirmed on the one hand by dating at use of radiocarbon and by the presented characteristics of the podzolization
T a b l e i
Total content o f various forma оС organio compounds
P r o f i l e No. L o c a l i t y Sampling depth cm Genetic horizon TotalC %
С оГ fu l v ie nr»d humic aeidn and humua, in % o f t o t a l С
H:F r a tio
Humification degree fr e e fra ctio n bounded fr a c tio n
V F 2 V H2 roz.iduumК PyP4,. i F 5 H -.+ H .+ 3 4 + н 5 huminea H 9. Cięciwa 1 -1 5 peat 2 0 . 1 9 6 5 . 1 14.1 7 9 . 3 0 . 7 0.6 0 . 2 2 . 5 4 2 0 . 7 A tla n tik u m 10-28 а1 Л2 0 . 5 0 2 2 . 2 5.4 3 7 . 8 2 0 .2 2 8 . 4 6 .0 1 .5 2 62.2 30-40 BH 0 . 5 9 4 2 . 3 1.7 2 1 . 9 4,= . 4 1 7 . 6 11.1 0 . 4 7 7 8 . 1 4 5 - 5 5 Bs 0 . 1 6 5 1 . 8 6 .0 7 . 3 1 9 . 9 2 0 .2 4 4 . 8 1 .1 9 9 2 . 7 3 Ciçciwii 1 - 1 0 peat 2 7 . 1 1 0 . 3 12 . 0 7 2 . 9 0.3 1 . 7 2 . 3 1 . 2 4 2 7 . 1 Atlantlkum 10-H Ai 1 . 1 6 3 5 . 8 8 .0 6 J.5 9 . 0 1 0 . 9 5 . 3 1 .2 5 3 9 . 5 20-30 % A2 1 . 1 3 2 9 . 4 1 1 .3 • 17 .1 1 3 . 3 1 2 . 8 5 . 6 1.06 5 2 . 9 3 0 - 4 0 A2 0 . 3 1 5 10.2 1 5 . В 2 1 . 9 1 4 . 6 27.0 10.5 1 . 7 3 7 8 . 1 4 0 - 5 0 % 1 .5 4 8 1 1 . 7 9 . 3 1 7 . 4 4 2 . 7 1 4 . 9 4 . 0 0 . 4 4 8 2 . 6 50-60 BS 0 . 3 0 9 0 . 3 0 . 9 4.8 2 1 .2 2 9 . 4 4 3 . 4 1 . 4 2 9 5 . 2 4 Cięciwa 0-10 / и O .16O 8 . 1 20.6 2 . 5 2 6 . 9 3 5 . 6 6 . 3 1 . 61 9 7 . 5 M s rod 1 6 K . K o n e c k a -B e tl e y
T a b l e 2
Some physico-chemical properties
Gene t i c Depth F re e P e 20 3 С F ree Fe % I r o n t r a r i s - l o c a t i o n
in d e x S o i l k in d L o o a lity h o riz o n s cm % % T o t a l С % C ięciw a p e a t 1-10 0 .1 7 5 10.091 No. 3 A1 10-14 0 .0 2 0 1 .1 6 3 humous a1a 2 20-30 0 .0 7 5 1 .1 3 2 p o d z o l A2 30-40 0 .0 2 5 0 .3 1 5 % 40-50 0 .1 6 1 .548 0 .0 7 2 6 .4 B s 50-60 0 .0 5 0 .3 0 9 0 .1 1 С 120-130 0 .0 2 n . d .
C ię ciw a p e a t 1-15 0 .2 5 2 0 .1 9 6 h u m o u s -fe r
No. 2 A1A2 h i B S 10-28 30-40 45-55 0 .0 1 5 0 .1 4 5 0 .0 6 5 0 .5 0 2 0 .5 9 4 0 .1 6 5 0 .1 7 0 .2 7 9 .8 ru g in o u s p o d z o l
process docum ented by the results of analyses on the other — Tables 1,
2 [1 1], viz. :
— the granulom etric composition of the soil in question proves a predominance of m edium -grained and as compared w ith other fractions [11, 2],
— the m ineral composition of heavy fraction proves a m uch higher w eathering degree of sandy m aterial as compared w ith soil of the Alleröd interstadial (O/N + S)= ratio betw een m inerals resistant to m echanical destruction and the sum of unstable and m edium -stable minerals), i.e.
a long-term soil-forming process (2, 1 1],
— a high acidification degree of soils (low pH, high hydrolytic acidity and low saturation degree w ith bases) suggests conditions for the form
ation of typical ferruginous-hum ous podzol {1 1, 2],
— the value of free iron translocation from the A t and A2 horizons
into the B H subhorizon m aintains w ithin the lim its of 6.8-9.6,
— the ratio betw een free Fe and to tal С in ,the (BH subhorizon ranges w ithin 0.07-0.17. It proves a considerable percentage of fulvic acids responsible for translocation of ferruginous-hum ous compounds, undergoing then to precipitation and stabilization,
— the occurence of high am ounts of hum ines in the Bs subhorizon proves in this case the occurrence of hardly-soluble complex compounds, m ainly w ith alum inium ,
— the ratio betw een hum ic and fulvic acids am ounts in the Л* horizon to som ewhat m ore th an 1 and in the B H subhorizon to about 0.4. It proves translocation of readily soluble hum us compounds from upper to deeper layers. A grow th of this ratio in the B s subhorizon is caused
by decreasing translocation of fulvic acids precipitated in the B H sub horizon and their partly polym erization to humic acids and form ation of humines.
R E C A PIT U L A T IO N
On the basis of investigations on occurrence of fossil sandy soils in dunes of the W arsaw environs as well as of biophysico-chemical investi gations of the most representable profile at Cięciwa, the following statem ents can be made :
1. The wholeness of ecologic conditions of late Pleistocene and early Holocene did not favour development of w ell-form ed soils w ith conside rable differentiation of genetic horizons. Namely, the ecosystems of th a t time were unstable and underw ent quick transform ations, w hat was responsible for form ation of w eakly-form ed soils.
2. The period favourable for the development of well-formed, m ature soils, is the climatic optimum of Holocene — the A tlanticum , w hen on dunes ferruginous-hum ous podzol developed, covered often in the ceiling w ith peat, proving stabilization of the ecosystems. The occurrence of peat finishes probably an intensive podzolization process. It can be presum ed th a t sometimes the podzol development began already in the pre-Boreal and finished in the sub-Boreal period only or even later, when the ferruginous-hum ous podzol or humous podzol w ith peat in the ceiling was covered w ith dune sand.
3. The investigations have proved th a t in the most representable profile at Cięciwa in the environs of W arsaw three fossil soils occur, in particular :
— the oldest, dated by means of 14C, of 11150 ± 1300 years of BP
(Lod 30), i.e. in the Alleröd interstadial. This soil type developed from middle Dryas sands and is usually a w eakly-form ed podzolized soil,
— the second fossil soil, younger than Alleröd, not dated by means
of 14C, developed on sands of the youngest Dryas on the tu rn of the pre-
-Boreal and Boreal period. It is rust-coloured soil, w ith rath e r w ell-form ed B T horizon, which could be superim posed in late periods by other soil- forming processes, among other things, by the podzolization process. If, however, this soil were covered w ith sand from blowings at the end of Boreal, it would form a separate soil horizon,
— the th ird fossil soil, form ed very well, developed from sands of the youngest Dryas, sometimes blown down, is of two dates : B H sub horizon of podzol dated 7150 ±150 years BP (Lod 47) and shallow muck developed from peat on this podzol soil dated 6155 ±270 years BP (Lod 31). A characteristic feature is the occurrence of iron pan of the leaching type, both in the B H and B s subhorizons.
tion of fossil soils should be, sim ilarly as contem porary soils, based not only on the wholeness of ecologic conditions and morphological features, b ut also on the wholeness of their biophysico-chemical features.
R EFEREN CES
[1] В a r a n i e с к a D. M. : D istrib u tio n and stra tig ra p h y of dunes in th e W arsaw en viron s. Rocz. glebozn. (in print).
[2] B a r a n i e c k a D. M. , K o n e c k a - B e t l e y K. : F o ssile soils of du n es in th e W arsaw en v iro n s and th eir stratigrap h ie im p ortan ce. P rzew o d n ik k o n fe r e n c ji teren o w ej K o m itetu B ad ań C zw artorzędu P A N i P olsk . T ow . G lebozn.,
38.
[3] B o r ó w k o - D ł u ż a k o w a Z. : Y ou n g p leisto cen ic and p o st-g la c ia l sites of fo s s ile flo ra at K onin. K w art, geolog. 23, 1979, 247-259.
[4] B o r ó w k o - D ł u ż a k o w a Z. : P a ly n o lo g ic a l and m a cro flo ristic e x p e r tise of fiv e flo o r sa m p les of th e p r o file at N art in th e K am p in os P rim a e v a l F orest (typ escrop t prepared for print), pp. 7 + diagram , 1980.
[5] C h m i e l e w s k i M. , C h m i e l e w s k i W. : S tra tig ra p h ie et ch ron ologie de la d u n e de W itów , d istrict de Ł ęczyca. B iu l. p ery g la c. 1960, 8, 133-141. [6] K obendza R., K o b e n d z i n a J. : B low n aw ay dunes of the K am pinos P ri
m a e v a l F orest. In lan d d u n es in P olan d , part I, 1958.
[7] K o b e n d z i n a J. : A ttem p t of d a tin g of d u n es of th e K am p in os P rim a e v a l F orest. P rzegl. geogr. 33, 1961, 3, 383-399.
[8] K o b e n d z i n a J. : G en esis of dunes. Rocz. glebozn. in print].
[9] K o n e c k a - B e t l e y K. : L ate p le isto c e n ic and h olocen ic fo s s il and r elict so ils o f th e O tw ock en viron s. Rocz. gleb ozn . 25, 1979, 3, 101-118.
[10] K o n e c k a - B e t l e y K. : S o ils of dune areas of cen tral P olan d in late g la c ia l and h olocen e. F o lia Q u atern aria 49, 1977, 47-62.
[11] K o n e c k a - B e t l e y K. : F o ssile and r elict so ils of d u n es of th e W arsaw en viron s. R ocz. glebozn. (in print).
[12] R ó ż y c k i S. Z. : P le isto c e n e of th e M iddle P olan d . PW N , 1979, 315. [13] S c h i l d R. : C h rom ostratigrap h ie et en v iro n o m en t in p a léo lith iq u e fin e l en
P ologn e. La fin d es tem p s g la cia ires en Europe, 1977, 271, 800-818.
[14] S c h i l d R. : A rch eo lo g ic a l stratigrap h y of in lan d d unes on th e basis of M azow sze dunes. Rocz. gleb ozn . (in print).
[15] S r o d o ń A . : P o la n d ’s v e g e ta tio n in th e Q u aternary. Szata rośl. P o lsk i 1, 1972, 527-569.
[16] W a s y l i k o w a K. : P o lle n a n a ly sis of th e la te -g la c ia l sed im en ts in W itów n ea r Ł ęczyca, m id d le P olan d . R eport of the 6th Int. Congr. on Q uaternary, V ol. II. P a leo b o ta n ica l sectio n 1961, 497-502.
K. K O NECKA-BETLEY
ROZW ÓJ PRO CESÓW G LEBOTW ÓRCZYCH PÓŹNEG O PLE IST O C E N U I HO LOC EN U W W Y DM A CH OKOLIC W A R SZ A W Y
In sty tu t G leb o zn a w stw a SG G W -A R
S t r e s z c z e n i e
K ilk u le tn ie bad an ia p a leo p ed o lo g iczn e ok olic W arszaw y, u d o k u m en to w a n e a n a liza m i fizy k o ch em ic zn y m i oraz d a to w a n iem ra d io w ęg lem i[9, 10, 11], p o zw a la ją w y d z ie lić w późn ym p le isto c e n ie i w c z e sn y m h o lo cen ie rep rezen ta ty w n y cy k l tw o rzen ia się śró d w y d m o w y g leb k op a ln y ch tego obszaru.
N a jsta rsza gleb a k oop aln a, d a to w a n a 14C n a 11.150 B P -L od . 30, w y tw o rzy ła się na w y d m ie środ k ow ego d ryasu. J e st to n a jczęściej g leb a słabo w y k szta łco n a b ielico w a n a . W za leż n o ści jed n a k od p o ło żen ia na stoku w y d m y p o w sta je ona ró w n ież jako gleb a słabo w y k sz ta łc o n a o glejon a lu b tw o rzy tzw . k om p lek s g le bow y sk ła d a ją cy się z k ilk u m ało m ią ższy ch p oziom ów p róch n iczn ych .
M łodsze g le b y w y tw o r z y ły się, w za leż n o ści od w a ru n k ó w g eom orfologiczn ych , już na p ia sk a ch w y d m o w y ch n a jm ło d szeg o dryasu . P ro cesy g leb o tw ó rcze rozpo częły się już w o k resie p reb orealn ym . N a p rzeło m ie p reb oreału i ok resu b o rea l- nego w y tw o r z y ła się m łod sza g leb a rd zaw a o dobrze w y k sz ta łc o n y m p oziom ie B T. G leb a ta albo została o b jęta d alej trw a ją c y m i p rocesam i g leb o tw ó rczy m i z w k r a czającą ro ślin n o ścią k lim a tu ciep lejsz eg o , albo — w przyp ad k u p rz e w ie w a n ia lo k aln ego p ia sk ó w — została zach ow an a.
T rzeci g leb a k op aln a, której p o w sta w a n ie n a le ż y w ią za ć z ok resem a tla n ty c kim , w y k sz ta łc iła się jako b ielica p róch n iczn a lub b ielica żela z isto -p ró ch n iczn a , w stop ie zw ień czo n a zm u rszałym torfem . T orf otrzym ał datę 6155 B P-Lod.31. C h a ra k tery sty czn ą cech ą tej g le b y jest w y stę p o w a n ie w podpoziom ach B H i B s r u d a w có w ty p u p rzem y w n eg o . P od p oziom B H d a to w a n o r a d io w ęg lem n a 7150 BP-Lod.47. N a p o d sta w ie p rzep row ad zon ych bad ań m ożna stw ierd zić, że ca ło k szta łt w a ru n k ó w ek o lo g iczn y ch p óźn ego p le isto c e n u i w c zesn eg o h o lo cen u n ie sp rzyjał sta b iliz a c ji ek o sy ste m ó w leśn y ch , a ty m sa m y m tw o rzen iu się g leb dobrze w y k szta łco n y ch . S ta b iliza cja ek o sy ste m ó w rozpoczyna się od b oreału i trw a przez op tim u m k lim a ty czn e h o lo cen u -a tla n tik u m , k ie d y na w y d m a ch tw orzą się b ie lic e z ch a ra k tery sty czn y m i ru d a w ca m i typ u p rzem y w n eg o .
P ro f. d r K r y s t y n a K o n e c k a - B e t l e y I n s t y t u t G l e b o z n a w s t w a S G G W - A R W a r s z a w a , ul. R a k o w i e c k a 26/32
