The evolution of the Darżyńska Struga valley as a combined effect of natural and anthropogenic processes

Badany obszar był przez ponad 30 lat przedmiotem zainteresowań archeologów, którzy odkryli tu wielokulturowe stanowisko obejmujące niemal cały okres od schyłku neolitu po wczesne średniowiecze.Wlatach 80. ubiegłego wieku wykonano pierwsze prace geomorfologiczne i geologiczne, które dały obraz daleko idących zmian dna doliny i ich zboczy, ale nie dały jednoznacznej odpowiedzi na pytanie, jakie przyczyny i w jakim okresie je spowodowały.Wostatnim czasie przeprowadzono rozpoznanie paleobotaniczne, które wskazało przede wszystkim na istnienie wielu luk sedymentacyjnych w osadach organicznych, ale dostarczyło też dowody na znaczne przekształcenia środowiska doliny Darżyńskiej Strugi, które dokonywały się zarówno u schyłku plejstocenu, jak i w średniowieczu.The investigated area has been researched by archaeologists, who discovered a multi-cultural site spanning the period from the latest Neolithic to the early medieval times, for more than 30 years. The first geomorphological and geological study, carried out in the 1980s, led to the recognition of substantial changes in the morphology of the valley floor and the valley sides, but left the question of their causes open. The more recent palaeobotanical prospecting revealed numerous hiatuses in the organic sedimentary record and indicated considerable environmental change in the Darżyńska Struga valley which took place in the latest Pleistocene and in the Middle Ages.In the latest Pleistocene the direction of meltwater drainage was to the south, using a part of marginal esker depression. After the valley of Łupawa was incepted, meltwater eroded a valley tract which is now the lower reach of the Darżyńska Struga. An erosional pavement (bed armour) originated in this way, currently underlying the valley fill. Parallel to climate change and increase in rainfall, particularly after the climatic optimum, peat accumulation commenced. In the Subboreal period Neolithic settlements were established in the proximity of the valley, quickly followed by intense denudational processes. The respective deposit is sandy diamicton of agricultural origin, prograding from the slopes onto the valley floor. Alluviation took place in the Middle Ages, as testified by pollen analysis and macrofossils from peat sediments, and was the consequence of floods redistributing slope sediments over peaty substratum. In the recent times channelization and drainage works have resulted in water level lowering in both the channel and within the floodplain