Landforms

Boqueixón’s 73.09 square kilometres lie on the right bank of the River Ulla, along its middle course. The municipality is made up of a succession of valleys and hills that slope down towards the Ulla. It is part of the so-called Santiago Step, the landform that stretches from the Galician Ridge towards the ocean as a worn-down peneplain that gradually loses height.

The terrain is generally gentle, broken in some areas by steeper, more rugged forms. This is the case in the west of the municipality, with the rocky outcrop of metagabbro on Monte Castelo (498 m), and in the south, with the quartz vein of the Pico Sacro range.

These two promontories are the highest points in the municipality, together with Pico Sacro itself, which reaches 534 metres. The lowest areas are in the south-east, in the parish of Ponte Ledesma, at barely 60 m.

Rivers

As mentioned, the municipality lies on the right bank of the River Ulla, while its northern boundary is on the southern slope of Monte Amenal, which forms the watershed between the Ulla and the Tambre. All the rivers in the municipality therefore flow into the Ulla.

Climate

The weather stations at Lavacolla airport (next to the municipality) and at Quián (Sergude) provide the key statistics for understanding Boqueixón’s climate.

The influence of the ocean is the defining feature of this climate. Temperatures are mild, with an annual average of 12.8 ºC, ranging from 7.4 ºC in January to 18.6 ºC in August.
Rainfall is abundant, averaging 1,872.4 mm a year, and spread throughout the year, with no dry month. December is the wettest month, while July is the driest.

Geology

Boqueixón’s geological map is divided into three main sub-zones. The first, made up of Precambrian schists and paragneisses of the Ordes series, is the largest (the parishes of Ledesma, Sucira, Oural, Pousada, Gastrar and much of Donas, Boqueixón, Loureda and Vigo).

The second sub-zone is characterised by outcrops of basic rocks, limited to narrow amphibolite intrusions. East of Santiago the amphibolites become much more extensive, appearing in the parishes of Lamas, Sergude, Boqueixón and Codeso, where they reach the River Ulla. The southern edge of these basic rocks is clearly marked by the great quartz dyke of Pico Sacro and its range, which separates the amphibolites of Sergude and Boqueixón from the granitised schists of Vedra.

Finally, the parish of Lestedo forms the third sub-zone, with two kinds of schist: albite schist, and, in the south of the parish, schists and gneisses of the Ordes series.

Besides these three sub-zones, there are various areas of alluvial plains and valley floors along the watercourses.