From volcanic plains to glaciated peaks : BURIAL, uplift and exhumation history of southern East Greenland after opening of the NE Atlantic

• In southern East Greenland (68-70°N), voluminous flood basalts erupted onto a largely horizontal lava plain near sea level at the Paleocene-Eocene transition when sea-floor spreading started in the NE Atlantic. Based on synthesis of geological observations, stratigraphic landform analysis and apatite fission-track analysis data in 90 rock samples, we show how three regional phases of uplift and exhumation subsequently shaped the present-day margin and controlled the discontinuous history of the Greenland ice sheet. A late Eocene phase of uplift led to formation of a regional erosion surface near sea level (the Upper Planation Surface, UPS). Uplift of the UPS in the late Miocene led to formation of the Lower Planation Surface (LPS) by incision below the uplifted UPS, and a Pliocene phase led to incision of valleys and fjords below the uplifted LPS, leaving mountain peaks reaching 3.7. km above sea level. Local uplift affected the Kangerlussuaq area (~. 68°N) during early Eocene emplacement of the Kangerlussuaq Intrusion and during late Oligocene block movements, that may be related to the detachment of the Jan Mayen microcontinent from Greenland, while middle Miocene thermal activity, coeval with lava eruptions, heated rocks along a prominent fault within the early Cretaceous to Paleocene Kangerlussuaq Basin. The three regional uplift phases are synchronous with phases in West Greenland, overlap in time with similar events in North America and Europe and also correlate with changes in plate motion. The much higher elevation of East Greenland compared to West Greenland suggests support in the east from the Iceland plume. These observations indicate a connection between mantle convection, changes in plate motion and vertical movements along passive continental margins.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Burial

Exhumation

Flood basalts

Geodynamics

Greenland

NE Atlantic

Peneplain

Thermonchronology

Uplift

Flood basalt

Basalt

Floods

Indium plating

Sea level

Stratigraphy

Tectonics

chronology

continental margin

glaciation

Miocene

Paleogene

plume

seafloor

temperature effect

volcanic eruption

Arctic

Atlantic Ocean

Atlantic Ocean (Northeast)

Kangerlussuaq Fjord

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