The Letea forest as seen from the trailhead (waypoint coordinates) .

Please note that the sand dunes are strictly protected, do not proceed beyond the above coordinates and do not leave the trail in the forest!
This earth cache leads you to the dune fields of Letea. These are - together with those of Caraorman further south - the largest dune fields in the Danube delta. Letea is the larger but younger of the two areas, with a length of 20 km and a maximum width of 15 km.
The dunes developed during the Holocene, i.e. some 5000 - 2500 years ago, and are one of the most pristine coastal dunes in Europe and therefore strictly protected. According to recent research [1], the Letea dune field was formed in several episodes. They were initially located close to the sea, were they formed around 2500 years ago by exchange of sediments with the beaches. Later, as the beach moved further seaward during the growth of the Danube delta, already present sediments were reworked. The most recent activity episodes occurred 240-70 yrs ago.

This area is also home of the Letea Forest, which is the oldest natural reservation in Romania, established in 1938. This was the nucleus of the Danube Delta Biosphere Reserve, which today is a World Heritage Site. The forest grows in rather narrow stripes in the dells between the dunes and represents the northernmost subtropical forest in Europe.

At the above coordinates you are at the edge of the dune field. Investigate the contact area between the forest and the dunes to find answers for the questions below and send them to the e-mail address in our profile

1) You will notice that the dunes are not stationary, identify their direction of movement; how did you find out?
2) What force do you think is behind the dynamics of the dune field?
3) This area also gives you information on the speed of this displacement. Estimate the approximate order of magnitude of that speed, e.g. a few meters per week/year/decade/century/millenium; and explain how you came to your conclusion.
4) (optional) Upload a picture of yourself and/or your GPS with your log, taken in the Letea area

The sand dunes are strictly protected, do not proceed beyond the above coordinates and do not leave the trail in the forest!

You can log the cache as soon as you have sent the answers, there is no need to wait for a log permission. If there are any problems with your answers we will get in touch ...

This EC is rated T5 because getting there is a multi day trip for most cachers, requiring a boat and local transport (or a really long hike). There is no climbing involved.

Sources:
[1] L. Preoteasa et al., Revista de Geomorfologie 11 (2009) 91
[2] Wikipedia - Letea Forest (RO, EN, DE)
[3] Homepage of the Danube Delta Biosphere Reserve
Photos: own work; flags: public domain

[RO] Ah căeăfvțv păeăevyr îa căqher !
[EN] Qb abg yrnir gur genvy !

[RO] Nu părăsiți cărările în pădure !
[EN] Do not leave the trail !