Editing Iturup (section)

==Geography==
Iturup consists of volcanic [[massif]]s and mountain [[ridge]]s. A series of a dozen [[Calc-alkaline magma series|calc-alkaline]] volcanoes running NE to SW form the backbone of the island, the highest being [[Stokap]] (1,634&nbsp;m) in the central part of Iturup. The shores of the island are high and abrupt. The vegetation mostly consists of [[spruce]], [[larch]], [[pine]], [[fir]], and mixed [[deciduous forest]]s with [[alder]], [[liana]]s and Kuril [[bamboo]] [[underbrush]]. The mountains are covered with [[birch]] and [[Siberian Dwarf Pine]] scrub, herbaceous flowers (including ''[[Fragaria iturupensis]]'', the Iturup strawberry) or bare rocks.

The island also contains some high [[waterfall]]s, such as the [[Ilya Muromets Waterfall|Ilya Muromets]].

[[Rheniite]], a [[rhenium]] [[sulfide]] mineral (ReS<sub>2</sub>), was discovered in active hot [[fumarole]]s on [[Kudriavy]] volcano and first described in 2004. In the field it was originally mistaken for [[molybdenite]].<ref>{{cite journal |last1 = Korzhinsky |first1 = M.A. |last2=Tkachenko |first2=S. I.|last3=Shmulovich|first3=K. I. |last4=Taran|first4=Y. A.  |last5=Steinberg|first5=G. S. |date = 5 May 2004 |title = Discovery of a pure rhenium mineral at Kudriavy volcano  |journal = [[Nature (journal)|Nature]] | volume = 369 |pages = 51–52 |doi = 10.1038/369051a0 |issue=6475 |bibcode = 1994Natur.369...51K |s2cid = 4344624 }}</ref>

=== Vetrovoy isthmus ===
The development of the Kuril Island arc was significantly influenced by extensive caldera-forming volcanic eruptions during the Late Neo-Pleistocene-Holocene, which introduced large amounts of pumice-pyroclastic material and tephra into the wave processing zone. On Iturup Island, the formation of four large collapse calderas during the Late Neo-Pleistocene-Holocene resulted in the release of about 450 km<sup>3</sup> of predominantly dacite pyroclastics.<ref> Melekestsev I V et al. 2005 The newest and modern volcanism in Russia (Moscow: Nauka) p. 604.</ref>

The formation of the subaerial Vetrovoy isthmus is attributed to the accumulation of such material during powerful explosive caldera-forming eruptions in the shallow strait between neighbouring islands.<ref> Korsunskaya G V 1958 The Kurile Island Arc (Moscow: Geographgis) p 224.</ref> The present geomorphological appearance of the isthmus is a consequence of subsequent wave and aeolian pyroclastic processing, leading to the formation of marine and lagoon terraces.<ref> Afanas'ev V V, Dunaev N N, Gorbunov A O and Uba A V 2018 Manifestation of Calderaforming volcanism in the formation of the sea coast (on the example of Iturup island of the Large Kuril Arc) J. Processes in geoenvironments 3. 16 990-98.</ref>

A study by Afanas'ev et al.<ref>Afanas'ev, V. V., et al. "Vetrovoy isthmus of Iturup island-holocene strait". IOP Conference Series: Earth and Environmental Sciences. Vol. 324. No. 1. IOP Publishing, 2019.</ref> focuses on examining the existence of the strait separating the southern and northern parts of Iturup Island in the mid-late Holocene from the perspective of coastal geomorphology. Late Pleistocene explosive volcanism is considered to have been more intense and prolonged than Early Holocene events, leading to the formation of pumice deposits in the Prostor Gulf of Iturup Island. Radiocarbon dating of the peat bog underlying the pumice-pyroclastic cover in the Vetrovoy Isthmus suggests events around 38,000–39,000 years ago.<ref> Bazanova L I, Melekestsev I V, Ponomareva V V, Dirksen O V, Dirksen V G et al 2016 Late Pleistocene and Holocene volcanic catastrophes in Kamchatka and in the Kuril Islands. Part 1. Types and classes of catastrophic eruptions as major components of volcanic catastrophism J. of volcanology and seismology 3. 151-69.</ref>

The stratigraphy, genesis and chronology of the Holocene deposits on Iturup Island are poorly studied, relying primarily on C14 dates from Kasatka Bay and Olga Bay[14]. Three transgressive phases of sedimentation, comparable to the Atlantic, Subboreal and Sub-Atlantic periods, with a maximum sea level rise of up to 3.5 metres above the present level in the Atlantic, have been identified at the mouth of the Kurilka River.<ref> Korotky A M et al. 2000 Sedimentation and paleolandscapes of the late Pleistocene-Holocene of the basin of the Kurilka river (Iturup island, Kuril Islands) J. Pacific Geology 5. 19 61–77.</ref>

Fieldwork conducted in 2017–2018 on the Vetrovoy isthmus revealed volcanic-tectonic dislocations with a layer of beach material, suggesting the occurrence of at least two pyroclastic outbursts in the mid-Late Holocene. Georadar surveys complemented the manual drilling results, providing insights into the geological features of the isthmus.<ref> Razzhigaeva N G and Ganzey L A 2006 Depositional environments of the island territories in the Pleistocene-Holocene (Vladivostok: Dalnauka) р 365.</ref>

The deposits of the Vetrovoy Isthmus include volcanic-tectonic dislocations, pumice pyroclastics, aeolian-ash deposits and soil-tephra formations. The morphometric parameters of the basement terrace indicate an area elevation rate during the last phase of coastal marine accumulation that could reach 4 mm/year, slightly higher than the 3.5 m/year recorded during the last 6000 thousand years.<ref> Bulgakov R F 1994 History of the southern islands of the Great Kuril Arc in the Pleistocene: autoref. Diss. of candidate of geogr. Sciences (Moscow: MSU) p 20.</ref>

In conclusion, several studies suggest that explosive volcanism in the middle Late Holocene significantly affected the morphotectonic plan of the Vetrovoy Isthmus area, possibly contributing to the obstruction of the strait. The rise of the terrace surface during the middle Holocene may be related to these volcanic events. The rate of uplift of the area during the last phase of coastal marine accumulation is thought to have been about 4 mm/year. However, there are currently no data on the age of the marine georadar facies identified as a result of research on the Vetrovoy isthmus.<ref> Razzhigaeva N G and Ganzey L A 2006 Depositional environments of the island territories in the Pleistocene-Holocene (Vladivostok: Dalnauka) р 365.</ref>