Svetloyar

The lake is located between the rivers Kerzhenets and Vetluga , left tributaries of the Volga. It has the shape of an oval with dimensions of 470 × 350 m with a long axis in the north-south direction, differs from the neighboring lakes by a great depth, reaching 33.4 m ^[2] . The deepest point is in the southern part of the lake, where the lowering of the bottom has the shape of a funnel, which is a continuation of the steep southern shores. To the north of this depression at the bottom there is a gentle platform 22-24 m deep . In the northern, relatively shallow part of the lake, the depth differences are smoother compared to the southern part. The height of the surface of the lake above sea level is 109 m . The shores of the lake are somewhat elevated, and it is located in a hollow; the hills encircling the lake are most distinctly manifested from the south, where they arc. The height of the hills reaches 122–124 m above sea level ( 13–15 m above the lake’s water edge), the hills are separated by deep ( 7–8 m ) ravines ^[2] . Extremely pure water of calcium bicarbonate type, transparent to a depth of more than 5 m . The lake is cold, it is fed by numerous bottom keys. The shores are slightly swampy ^[2] . At 0.5 km to the northeast there is a small shallow river Lunda , with which the lake is connected by a stream. The runoff from the lake through a stream, partially disturbed during the construction of the road in Soviet times (as a result, the lake began to bog down), was restored in the 1990s.

The volume of the lake basin (not the lake itself) is about 1.5 km ³ , the water surface area is 14.83 ha . The sediment thickness is about 8 m ^[2] .

The lake is located on the territory of the Voskresenskoye Povetluzhje natural park (a protected zone of the Nizhniy Novgorod Poveluzhi, a natural park of regional significance) created in 2008.

The view of the origin of the lake has changed since the time of its study and has not yet been resolved unequivocally. At different times, various researchers have come up with hypotheses about the glacial, karstic, ancient, volcanic, neotectonic, salt dome and cosmic meteorite origins of the lake. The first explorer of the lake at the end of the XIX century. was the great Russian soil scientist V. V. Dokuchaev , and he owned the first version of origin: the lake is a meteorite crater. The volcanic origin of the lake was first suggested at the beginning of the 20th century by writer V. Korolenko .

At the end of the 19th century, students of Kazan University did research on the lake. Also during this period, the amateur-archaeologist A.P. Polivanov conducted excavations on one of the Svetloyarsky hills and discovered the remains of ancient tools belonging to the Stone Age.

In order to study a whole range of problems, in the late 1960s - early 1970s. A public integrated scientific expedition of the Literary Gazette under the leadership of MM MM Barinov worked at Svetloyar. The expedition scuba divers established in 1968 , and the geoacoustic studies on the lake area in 1969 detailed the complex structure of the bottom relief of the lake. The central pit-basin is bordered by a system of two underwater terraces, expanding in the northern and tapering in the southern parts of the lake and having a depth of 18–20 and 9–10 m, respectively. It was suggested that the multi-stage cyclically-periodic formation of this very young lake in the scale of geological time as a result of neotectonic processes. Based on this, it was concluded that the central basin formed a little more than a millennium (approximately 1100–1200 years ago) in the form of a small lake of 15–17 m depth, and the lower terrace dipped approximately 700–800 years ago, which quite accurately corresponds to the time of the Batu invasions ( 1237–38 ).

Recently, a number of studies confirm the meteorite hypothesis of the origin of Svetloyar and some neighboring lakes ^[3] . In 2009, the results of field studies were published, confirming the hypothesis about the meteoric origin of the lake 3.0–3.2 thousand years ago ^{[4] [5]} .

The meteorite origin of the lake is evidenced by the correct shape, depth, geological structure of the surrounding hills, stratigraphy of bottom sediments, numerous fragments of fused rocks, rounded drop-shaped formations of black foam glassy mass, similar to impactites . The celestial body, which created Svetloyar, could move from north to south along a low trajectory at an angle of 30-40 ° to the Earth's surface ^{[4] [5]} .

In 1993, the film of the creative association "Screen" "The Tale of the Great and Invisible City of Kitezh" (author and director V. Kukushkin) was released, "about mythological roots and the search for the invisible" Grada Kitezh "under the surface of the Svetloyar Lake in the Nizhny Novgorod region" (abstract quote from the website of the State Television and Radio Committee of the RF) The film was shown on the first channel of Central Television on Easter on April 17, 1993, before the first television broadcast of the Easter service from the Epiphany Cathedral in Moscow.

• It should not be confused with Svetloyarsky lake in Sormovsky district of Nizhny Novgorod . The latter arose in the 1970s as a result of the construction of the plant and is called "Svetloyarskoe" (and not Svetloyar), which just indicates its secondary nature.

• Great Holy Lake

• Map sheet O-38-XXVIII . Scale: 1: 200 000. The state of the terrain in 1979. 1986 edition

• Natural Park "Resurrection Povtluzhje"
• Svetloyar
• Virtual panoramic tour around the lake
• References about Svetloyar
• Photos of a wooden Kazan church-chapel on the shore of Svetloyar lake
• Mystery Svetloyar. The plot of the Roscosmos television studio .
• Svetloyar - Russian Through the Looking Glass Film of the Roscosmos TV Studio .