Focus on Geology ACADEMIA 18 No. 1 (45) 2015 to lie at an altitude of around 630-680 meters to 630-680meters lieatanaltitudeofaround isconsidered river Republic. ofthe Thesource Opava Czech inthe of the a range Mountains story? its is turbulent How (Oder),Odra Poland’s river? number-two the about special so is What Paleolithic. middle the in back settlers attracted already structure and position geographic Its period. Tertiary the ago,in back years million 10 than more began history Its of University Wrocław.the at Mapping Geological and Geology Structural for Section the of head currently Society,Geographical is Polish he the of branch Silesian Lower the of Park,president National and Mountains Poland’sof scholar, initiators Humboldt the TableA of one Sudetes.the and massif Czech the of reconstructions cartographer,paleogeographical and in specializing Asst.geologist,Prof.a sedimentologist, Jurand is Wojewoda of University Wrocław Geology, of Institute JURAND WOJEWODA Curiosities of River A River Odra the of story distinctive The basin includes nearly the entire area of the ofthe area entire basin includesnearly the itscatchment isalsodistinctThe Odra inthat Black into Danube, draining Sea). the of the river, Morava 352 km, a tributary (around the Sudeten third-largest level, ofthe asdoesthat Elbeliesatabout1380meters abovethe sea of source elevation source –the oftheir terms respectively). However, in greatly differ they (at118,861km2and144,055km2, rable two Sudeten compa ofthe are areas rivers Elbe).Interestingly, the (after catchment the Sudetes outofthe second-longest flowing river Vistula) andalsothe inPoland the river (after BalticSea. directly to the headsnorth, it again Lusatian Neisse, which itmeetswhere after the way allthe to bearing that and maintains Foothills. Near northwest Koźle to the itturns Moravian Gate Sudeten into the the through and flows northward turns river the ous region, mountain leaving after the In itsuppercourse, above sealevel,slopesofMountVysoká. onthe The Odra flows out of the Odra Mountains, Mountains, Odra outofthe flows The Odra Running 854 km, it is the second-longest second-longest Running 854km,itisthe - - Cretaceous age. Thesecondcut,nearŚcinawa, and elevatedTriassic of the rocks calcareous tectonically Oderchannel cutsthrough the vicinityofOpole,where is situated inthe such gorge Thefirst danger offlooding. the watersWhen river localtowns swell, the face valley anddeep. isnarrow locations,the these andeach timeitchangesthrough, At direction. itcuts that itencounters uprisings depression, Valley. Odra Proglacial timesalongthis Three ancient known 20 km across, as the than more sometimes depression, abroad through flows region. tion inthis Sudetes, precipita most andsoitdrains ofthe paleogeographic sense, on the other hand, other sense,on the paleogeographic million and180years ago.Inthe istoly say thereafter, that between 320 Variscanas the orogeny and immediate atimeknown during were formed of them 500 millionand60years ago.Most andwere ofEurope ture created between geological struc ofthe part currently are Sudetes made out of the are that The rocks sense. geographical ways the coincidewith doesnot “mountains” al term sense ofthe geological the that should pointouthere We forming. started then range mountain Sudeten the where area the from flowed (or“pre-Odra”), ancientOdra the of those, zone oftoday’s Poland. Thelargest southern inthe sources itfrom across flowing rivers Poland Great to Lowlands the had already today’sfrom Sudeten way Foothills allthe region middleMiocene)the ago (back inthe 10millionyears that Sudetesof the agree Warta (respectively)moraines ofthe Stadial. andground terminal which ofthe relicts are LesznoLakeland, the Hillsfrom Zielona Góra incision,east ofNowa third Sola,separates the westthe (200-250mabove sealevel). The Dalkówskie eastHills to andthe the Hillsto StadialOdra into Trzebnica two the ranges: of the moraine of terminal separates astrip In the Lower Silesian segment, the Odra Lower Odra In the Silesiansegment,the Geologists paleogeography studying the power Cutting - - - -

BE&W ACADEMIA Panorama Geologia

No. 1 (45) 2015 19 For the residents of whose day-to- Wrocław, day lives involve crossing numerous waterways (the urban agglomeration alone having more than 300 bridges and footbridges!), the presence of water in the city is something completely normal, forming an integral part urban Wrocław’s fabric of But and visitors landscape. from outside are frequently getting the astounded, impression that the city is “built on water…” - From the modernFrom glaciations to times, last Somewhat later, the advancing ice sheet later, Somewhat west towards the and broad German towards lowlands west the North Sea. It carved out the broad ancient part is used by of which Proglacial Odra Valley, the of the recent channel Odra. the area has been uplifting, Sudeten marking This occurred along the line of one of the most –Silesia Lower in faults importanttectonic Some of thethe new Marginal Fault. Sudetic rivers in theSudeten ancient Odra basin began flowto in the direction, northward, opposite valleys. the utilizing still-existing likely most from the north the reached front of the uplift flowing The waters out both froming Sudetes. the melting ice and from the region of today’s then which formed broad a Sudetes, elevation, virtually the materialdeposited over entire area Silesia and southernof Lower Great Poland. halting of theThe successive Scandinavian bands of moraines, created formingice-sheet a series of moraine hills after During it retreated. thereafter,the and immediately Odra Stadial theflowing waters from the and the ice-sheet pre-Odra a great combined into river flowing - - - - It was not until relatively recently, in the recently, until relatively not It was In the Miocene, around 8 million to late radically, as a result of a process known as “in as resulta as processof a known radically, Foothills Sudeten The area of today’s version.” uplifted. while the range was Sudeten lowered, largest Sudeten rivers, including the Sudeten pre-Odra,largest form.began to ago), before (around 2 million years Pleistocene the into vi advanced the ice sheet Scandinavian cinity of the (a time described as as the Sudetes pre-glacial period), that the landscape changed that river is illustrated, for instance, by the by that fact instance, for riveris illustrated, that it cut through the emerging massifs of the forming one of the larg Carpathian orogeny, in this gorges est part of Europe (the Morava can assume with great likelihood We Valley). that then of the it was that of valleys the system 5 million years ago, the5 million years area of the Sudetes and formed Foothills compact a Sudeten and the from massif, moderate-sized which first ancient rivers flowed in a radial pattern, in at thatall directions. un The largest time was the The mighty scale ofdoubtedly pre-Morava. the Sudetes are a set of mountain ranges,the are a set Sudetes and basins of very origins. diverse valleys, Focus on Geology ACADEMIA Poland. In the Pleistocene,Poland.the In ago,years million 20 when Proglacial Odra was Proglacial Valley some of them flowing into into flowing them of some the pre-Morava basin and and basin pre-Morava the the pre-Odra.the ancient The the sea”“Pre-Carpathian the late Miocene,late around the north-flowing rivers that that rivers north-flowing began to emerge around around emerge to began formed the new basin of of basin new the formed formed back in the Odra Odra the in back formed continues to be used by by used be to continues Stadial and immediately immediately and Stadial folding and at the same same the at and folding rivers flowed from what what from flowed rivers in Lower Silesia already already Silesia Lower in southeast of Europe.of In southeast watershed between the the between watershed the upheaving Sudetes Sudetes upheaving the the modern channel of of channel modern the south-flowing rivers of of rivers south-flowing in the south of today’sof south the in is today’sScandinavia,is system of river valleys valleys river of system time upheaving in the the in upheaving time set established a new new a established set 8-5 million years ago,years million 8-5 The outline of today’sof outline The the Carpathians were were Carpathians the thereafter, it and 20 No. 1 (45) 2015 the Odra.the

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No. 1 (45) 2015 21 Our knowledge of the ancient Odra River is based mainly on the results of geological, and geomorphological, archeological research. It is only to a certain approximate extent that can reconstruct the historical Odra and its related canals on the Wrocław map of - n [Odra Dorzecze [The Bridges of Geologia i Paleogeografia Mosty Wrocławia Mosty

[Geology and Paleography of Wrocław]. Wrocław] Wrocław: Ossolineum. Wrocławia Wrocław: KGHM CUPRUM CBR. lipiec 1997 monografiaOdry, powodzi Tributaries: The Flood of July IMiGW. 1997]. settlement. Most of the existing water-bodies water-bodies of the Most existing settlement. are relicts of transport canals, mill leats, and fragmentarily preserved moats of defensive from The older moat, dating the 13ththe city. as the on also known Czarna Oława, century, account of the of the quick expansion city its construc before value its defensive lost being used still It was completed. tion was as an urban canal in the mid-19th century, filled was it afterturnedand in which into moat, The younger an internal city artery. whose construction begun in the was 15th in 1810, century completed and ultimately landscape has remained in the Wrocław performed though it never even a defensive should mention that of the most function. We built in were city-center arteries in today’s place of filled-in transport medieval canals. based on and floodway system A boatway principlesmedieval therefore contributes to Wrocław. the normal of today’s functioning in 1905-1908, Its construction completed was is underway. and modernization work configurationand Odra of islands (islets) some of them Only arechannels. reminiscent thein shape and course to river prior to Szponar A., Szponar A.M. (2008). A.M. Szponar A., Szponar Dubiecki A., Słota H., Zieliński J. (Red.) (1997). eastern elevation Further reading: Łagiewski M. (1989). - - -

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anastomosing channel Today’s braids of the Odra are in large Today’s part human-altered. The area of Wrocław’s part The area human-altered. of Wrocław’s centuries-long a has history of town old and rebuilding of thesettlement original pre-Odra are also found at a similar, elevated po elevated pre-Odra at a similar, are also found in near the valley sition with today’s respect to where coarse residual of Chrząstawa, village more deposits (some boulders reaching channel than greatly the hamper 3m in diameter) local quartz sand mining efforts. some 10 m above the bottom of today’s Odra today’s of the bottom above m 10 some It formed through river erosion and is valley. of the deposits channel in Odra,ancient covered when thefrom back river’s appearance was thatsimilar to of the braided large rivers of the Deposits of theCanada and Siberia. a similar. In landscape. One of thesethe in can be found southern along ul. Hallera, portion of Wrocław where traces of human activity from the middle Paleolithic of the among sediments are situated pre-Odra. in this substratum The geological whose surfacelocation is a plateau, is situated The fact thatThe fact smaller rivers and streams several Node”) Water theas known “Wrocław (together and Ślęza – flow Widawa – including the Oława, the confirmsinto Odra within that Wrocław the stable by clearly indicated It also tendency. theof substra elevations of location geological tum, preserving of the characteristics ancient serving numerous communication, defense, and economic purposes. In its central-Wrocław is a typical multichan segment, the Odra Valley under a type which river, nel anastomosing channels and formsconditions valleys lowland in areas with declining tendency. a consistent