Great Lyakhovsky Island edit
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Great Lyakhovsky Island edit
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| Native name: Большой Ляховский | |
 Map showing the location of Lyakhovsky Islands |
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| Geography | |
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  Great Lyakhovsky Island (Russia)
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| Location | between the Laptev Sea and East Siberian Sea |
| Coordinates | |
| Archipelago | New Siberian Islands |
| Area | 4,600 square kilometres (1,800 sq mi) |
| Highest point | Emy Tas (270 metres (890 ft)) |
| Country | |
 Russia |
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Great Lyakhovsky Island (Russian: Большой Ляховский: Bolshoy Lyakhovsky) is the largest of the Lyakhovsky Islands belonging to the New Siberian Islands archipelago between the Laptev Sea and the East Siberian Sea in northern Russia. It has an area of 4,600 km², and a maximum altitude of 270 m (Emy Tas).1
The peninsula projecting towards the west of the island is the Kigilyakh Peninsula (Poluostrov Kigilyakh).
Off Great Lyakhovsky Island's southwestern cape lies a small islet called Ostrov Khopto-Terer.
The Lyakhovsky Islands are named in honour of Ivan Lyakhov, who explored them in 1773.
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Great Lyakhovsky Island consists of highly folded and faulted Precambrian metamorphic rocks and turbidites; Mesozoic turbidites and igneous rocks; and Cenozoic sediments. Exposed in southeastern part of this island, the older Precambrian. Early Proterozoic, metamorphic rocks consist of schists and amphibolites. Small exposures of Late Proterozoic schistose, quartzose sandstones and phyllitic, sericite-quartz schist (turbidites) also occur in the southeastern part of Great Lyakhovsky Island. The bulk of this island consists of Late Jurassic to Early Cretaceous turbidites composed of interbedded fine-grained sandstones, thinly bedded siltstones, and argillites. The Precambrian and Late Jurassic to Early Cretaceous rocks are intruded by Late Cretaceous granites and granodiorites.234
A blanket of unconsolidated Cenozoic sediments blankets most of Great Lyakhovsky Island. These sediments include Paleocene to Eocene colluvial, alluvial, and deltaic gravels, sands, clays, and coals and Oligocene to Miocene alluvial, lacustrine, deltaic, and nearshore marine sands and clays that contain beds and lenses of gravel. Overlying these sediments are Pliocene to Pleistocene colluvial, alluvial, and nearshore marine sands, silts, and clays clays that contain occasional gravel layers. The nearshore marine sediments contain the shells of marine mollusks and pieces of lignitized wood. Thick permafrost characterized by massive ice wedges has developed in these sediments.35 Contrary to the interpretations of Baron von Toll6 and earlier geologists, glacial deposits and ice are completely absent within Great Lyakhovsky Island.
Detailed geological studies, which included the radiocarbon dating of bones, ivory, and plant remains; optically stimulated luminescence dating bone-bearing sediments; and uranium-thorium dating of associated peats, have clarified the stratigraphy, origin, and age of the sediments and permafrost that Baron von Toll6 found exposed in the southern sea cliffs of Great Lyakhovsky Islands. Dr. Romanovsky7 and Dr. Andreev and others8 found that these bone- and wood-bearing sediments described by Baron von Toll6 consist of Middle to Late Pleistocene floodplain and thermokarst, eolian, and lake sediments underlying different terrace levels. Later studies determined that alders, Alnus fruticosa, lived within the New Siberian Islands only during relatively brief periods of warm interstadial and interglacial climates. Dr. Makeyev and others9 found that over the last 15,000 years, Alnus fruticosa occupied these islands from 12,200 to 12,500 radiocarbon years BP during an interstadial that was unrelated to Baron von Toll's6 "mammoth period". Dr. Andreev and others8 dated the sediments also containing alder pollen and Baron von Toll's6 alder tree to the last, Kazantsevo (Eemian), Stage about 114 to 130 thousand years ago. They found that other vertebrate fossils ranged in age from 114,000 to 26,000 BP. These Pleistocene sediments, overlie a Pliocene paleosol and are cemented by permafrost.897
Baron Eduard von Toll6 made an interesting discovery. Under a peat composed of water mosses covering what is described as the "perpetual ice", Baron von Toll found fragments of willow and the bones of post-Tertiary mammals, like the shoulder-bone of a saber-toothed tiger. It also reported having found in a frozen, sandy clay layer and lying on its side, a complete tree of Alnus fruticosa 15 to 20 ft (4.5 to 6 m) in length, including roots, with leaves and cones adhering. Various authors, i.e. Dr. Digby10 and Dr. Kropotkin11 misreport this tree as being 90 feet (27 m) high. Other publications, i.e. Fingerprints of the Gods12 and Earth's Shifting Crust13 not only incorrectly state that this alder tree is 90 feet (27 m) high, but also they also repeat fictional claims from unreliable sources that this tree was either a “fruit tree” or “plumb tree” and had "green leaves"and green fruit" still attached. Lacking modern radiocarbon dating techniques, Baron von Toll6 assigns this tree to what it calls the "mammoth period". It concludes that this alder tree is proof that tree-vegetation had reached the seventy-fourth degree of latitude, three degrees farther north than it is found at the present time at this time.
The Cape Shalaurova meteorological station, which lies on the southeast coast of Great Lyakhovsky Island, at 73° 11' N 143° 56' E provides climatic data for this island. The mean precipitation is 184 mm/year as calculated for a 7 year period between April 1994 and September 2000 as calculated from National Oceanic and Atmospheric Administration data. The heaviest precipitation, about two-thirds of the yearly total, occurs between June and September. As calculated from the same data for the same period of time, the mean temperature at Cape Shalaurova is -13.6°C. January is the coldest month with a mean temperature of -31.0°C and August is the warmest month with a mean temperature of 2.4°C. Mean daily temperatures range as low as -40.5°C and as high as 9.4°C.9
The vegetation of Great Lyakhovsky Island is a mixture of rush/grass, forb, cryptogam tundra, cryptogam herb barren, and sedge/grass,moss wetland. The rush/grass, forb, cryptogam tundra covers the bulk of Great Lyakhovsky Island. It consists mostly of very low-growing grasses, rushes, forbs, mosses, lichens, and liverworts. These plants typically cover about 40-80 percent of the surface of the ground. The soils are typically moist, fine-grained, and often hummocky. The cryptogam herb barren consists of dry to wet barren landscapes with scattered, herbs, lichens, mosses, and liverworts. Sedges, dwarf shrubs, and peaty mires are normally absent. These plants form a sparse (2-40%) and low-growing plant cover that often occurs as dark streaks on the otherwise barren lands, composed largely of bryophytes and cryptogamic crusts. Sedge/grass,moss wetlands, which occur on the northwest and southeast ends of Great Lyakhovsky Island, consist of wetland complexes dominated by sedges, grasses, and mosses. These wetlands occupy low, perennially wet parts of the landscape.14
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