The Mainz Sand Dunes (german: Großer Sand) are a small geological and botanical supra-region and important nature preserve in

Mainz Mainz () is the capital and largest city of Rhineland-Palatinate, Germany. Mainz is on the left bank of the Rhine, opposite to the place that the Main (river), Main joins the Rhine. Downstream of the confluence, the Rhine flows to the north-we ...

, Germany. Within this protected area rare plants and animals can be found. Some of the species represented here, such as the Purple Golden-drop, (''

Onosma ''Onosma'' is a genus of flowering plants in the family Boraginaceae. They are native to the Mediterranean and western Asia. They grow in dry, sunny habitats with rocky, sandy substrates.Koyuncu, O., et al. (2013)A new ''Onosma'' (Boraginaceae) s ...

arenaria'') grow only here and in small numbers. The sand dunes developed after the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

(

Würm glaciation The Würm glaciation or Würm stage (german: Würm-Kaltzeit or ''Würm-Glazial'', colloquially often also ''Würmeiszeit'' or ''Würmzeit''; cf. ice age), usually referred to in the literature as the Würm (often spelled "Wurm"), was the last g ...

) and the first resettlement of

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

plants occurred approximately 12,000 years ago. The dry sandy soils are poor of nutrients but relict flora from the glaciation grasslands grow favorably. These plants are found otherwise only in southeast-European, inner-Asiatic (

Pontic Steppe Pontic, from the Greek ''pontos'' (, ), or "sea", may refer to: The Black Sea Places * The Pontic colonies, on its northern shores * Pontus (region), a region on its southern shores * The Pontic–Caspian steppe, steppelands stretching from nor ...

) areas and in the Mediterranean respectively. The effective surface of the protected landscape is rather small at 1.27 square kilometers. The Sand Dunes can be found between the suburbs

Gonsenheim Gonsenheim is a borough in the northwest corner of Mainz, Germany. With about 25,000 inhabitants, it is the second-most populated borough of Mainz, before Oberstadt and after Neustadt. History Protohistory The history of Gonsenheim reaches bac ...

and

Mombach Mombach, with 13,875 inhabitants (Apr. 2021), is a borough in the northwest corner of Mainz, Germany. Mombach can be reached via Mainz-innenstadt (downtown) or Bundesautobahn 643. Location Mombach is located on the southern (left) bank of the ...

and stretches up to the

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

s beginning in Mombach. Bordering the dunes is the

Lennebergwald The Lennebergwald is a forest in the north of Rheinhessen in Rhineland-Palatinate in Germany. The approximately 700 ha sized stretches north-west of Mainz between the urban districts of Mombach, Gonsenheim, Finthen and the municipalities of Bud ...

, with an area of 7 km² and therefore the biggest contiguous forest in

Rheinhessen Rhenish Hesse or Rhine HesseDickinson, Robert E (1964). ''Germany: A regional and economic geography'' (2nd ed.). London: Methuen, p. 542. . (german: Rheinhessen) is a region and a former government district () in the German state of Rhineland- ...

. The Lenneberg forest is also protected and shows to some extent the same flora and fauna.The Mainz Sand Dunes Nature Reserve
by Ralf Eichberger

The development of the sand dunes

In the late

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

, just before the end of the last ice age and during the short summers, sand-drifts were blown from the

Rhine ), Surselva, Graubünden, Switzerland , source1_coordinates= , source1_elevation = , source2 = Rein Posteriur/Hinterrhein , source2_location = Paradies Glacier, Graubünden, Switzerland , source2_coordinates= , so ...

Valley into the area of the present dunes, forming this unique geology. The soil consists almost solely of high lime component with fine white sand, which barely retains water and nutritive but is easily warmed by sunlight.

References

{{coord, 50, 00, 55, N, 8, 12, 25, E, region:DE-RP_type:landmark, display=title Dunes of Germany Geography of Mainz Nature reserves in Rhineland-Palatinate Landforms of Rhineland-Palatinate