Abstract
<jats:p>The Sielpia Reservoir is located on Czarna Konecka River in the N part of Świętorzyskie Voivodeship (Central Poland), about 30 km NW from Kielce. In the Middle Ages, there was a significant development of metallurgical industry in Old-Polish Industrial District (OPID). The Sielpia Reservoir is in place where one of historical industrial pond operated. Suddenly other reservoir drainages and disastrous flows in the middle section of the Czarna Konecka River led to intensified incision and bank erosion of the river and intensive accumulation of material in the Sielpia Reservoir. In the Czarna Konecka estuary into the Sielpia Reservoir an inland delta (high energy subequenus fan) was deposited. These fan and inland delta were formed during many flash floods caused by failures of the dams of former industrial ponds located upstream of the reservoir. A geological profiles in inland delta were made, and samples were taken for grain size analysis, macro-, microslags and iron spherules content by Magnetic Spherule Separation (MSS) method. The analyses have shown the occurrence of slags and iron spherules in fan sediments. Slags are mainly accumulated quite shallowly creating later characteristic aeolian pavement. Mainly delta fan is built by sandy sediments at terraces cut by the river, in which both slags and spherules do not occur. A small amount of them in the inland delta sediments confirm their redeposition from the upper section of Czarna Konecka River during flood events.</jats:p>