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The South Chukchi-Hope Tectono-Sedimentary Element rests on the Neocomian folded basement formed as a result of the South Anyui palaeo-ocean closure. The interpretation of 2D seismic data as well as results of onshore structural field studies and dating of post-kinematic granite plutons suggest post-collisional extensional/transtensional regimes, potentially driving development of the South Chukchi-Hope Basin. The orogenic collapse occurred during the Aptian-Albian and followed by continued poly-phase extensional/transtensional regime during the Late Cretaceous and Cenozoic. Depositional environments in the basin were most likely non-marine in the Cretaceous and Early Tertiary and marine from the Late Oligocene (?) - Miocene onwards. Three onshore wells in the adjacent depocentres penetrated Tertiary sediments and have had gas shows from two sites. Geochemical surveys registered anomalies of thermogenic and biogenic methane and in some instances higher molecular ethane to penthane gases in sea-bottom sediments above gas chimneys observed on seismic lines. The tectono-sedimentary element is characterized by a very high present-day thermal gradient of up to 48 deg. C/km recorded in the Alaskan wells and was previously considered to be gas-prone.

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