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Bolshoy Lyakhovsky Island

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Bolshoy Lyakhovsky Island is a major landmass in the Arctic. It is the largest island in the New Siberian Islands archipelago. This island sits in northern Russia between two bodies of water. These are the Laptev Sea and the East Siberian Sea.

Kigilyakh Peninsula of Bolshoy Lyakhovsky Island 2010-09-28
Kigilyakh Peninsula of Bolshoy Lyakhovsky Island 2010-09-28

The Kigilyakh Peninsula projects toward the west of the island. Near the southwestern cape, there is a small islet called Ostrov Khopto-Terer. The highest point on the island is a peak named Emy Tas. The island's name honors Ivan Lyakhov, who explored the area in 1773.

The geology of the island is very complex. It consists of several different types of rock from different eras. At the bottom, there are Precambrian metamorphic rocks and turbidites. These are highly folded and faulted rocks. Some of these include schists and amphibolites. Above these are Mesozoic rocks, such as turbidites and igneous rocks. The bulk of the island contains Late Jurassic to Early Cretaceous turbidites. These are made of fine-grained sandstones, siltstones, and argillites. Late Cretaceous granites and granodiorites also intrude these layers.

Most of the island is covered by a blanket of Cenozoic sediments. These are loose materials like gravel, sand, and clay. These sediments were moved by rivers, deltas, and lakes. Some layers contain coal. Other layers include sands and clays from the Oligocene and Miocene periods. These nearshore marine sediments often contain mollusk shells and pieces of wood. A very important feature here is the thick permafrost. This permafrost contains massive ice wedges. These wedges formed within the sediments over long periods of time.

Scientists have studied the southern sea cliffs in great detail. Baron von Toll was one of the first to study these cliffs. He discovered many fossils within the layers. In the 1990s and 2000s, a Russian-German team studied the area further. They looked at the cryolithology, which is the study of frozen ground. They also studied paleobotany, which is the study of ancient plants. They used radiocarbon dating on bones and ivory. They also used uranium-thorium dating on peat to find exact ages.

The layers of sediment tell a story of changing climates. The Saalian sediments accumulated between 200,000 and 120,000 years ago. These include an ice complex that formed between 200,000 and 170,000 years ago. Scientists found pollen from sparse grass-sedge vegetation in these layers. This indicates a cold environment called a stadial. Other layers show pollen from dense grass-dominated tundra. This shows an interstadial, or a warmer period. These changes show how the Arctic environment shifted over thousands of years.

Other layers provide even more clues about the past. Eemian lake sediments fill depressions in the ground. These depressions are called thermokarst lakes. They formed when permafrost thawed during warmer interglacial periods.

Malakatyn B.Lyakhovsky Island 2010-09-28 Boris
Malakatyn B.Lyakhovsky Island 2010-09-28 Boris

In the Middle Weichselian period, between 50,000 and 28,000 years ago, ice complex deposits formed. These contained pollen from the mammoth tundra-steppe. This was a swampy habitat under an extremely cold climate. These layers help us understand the massive animals that lived there.

The permafrost acts like a natural preservation system. It keeps prehistoric bones, shells, and plants from decaying. Because the ground stays frozen, these items remain abundant. Vertebrate fossils have been found in layers ranging from 114,000 to 8,000 years old. This includes remains from the Last Glacial Maximum. Even though some layers were eroded, others remain well-preserved. This makes the island a vital site for studying Earth's history. It connects geology, biology, and climate science together.

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File:Kigilyakh Peninsula of Bolshoy Lyakhovsky Island 2010-09-28.jpg
Kigilyakh Peninsula of Bolshoy Lyakhovsky...
File:Malakatyn B.Lyakhovsky Island 2010-09-28 Boris.jpg
Malakatyn B.Lyakhovsky Island 2010-09-28 Boris.jpg
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