TY - JOUR

T1 - A new vertebrate fossil-bearing layer in the Rhætelv Formation (Kap Stewart Group) of central East Greenland

T2 - evidence of a Hettangian marine incursion into the continental Jameson Land Basin

AU - Clemmensen, Lars B.

AU - Lindström, Sofie

AU - Mateus, Octávio

AU - Mau, Malte

AU - Milàn, Jesper

AU - Kent, Dennis V.

N1 - Funding Information: We gratefully acknowledge support from Dronning Margrethes og Prins Henriks Fond, Arbejdsmarkedets Feriefond, Oticon Fonden, Knud Højgaards Fond, Louis Petersens Legat, Det Obelske Familiefond, Ernst og Vibeke Husmans Fond, the Independent Research Fund Denmark, GeoCenter Møns Klint and GEUS. We are grateful to Gregers Dam for discussions on the stratigraphy of the Kap Stewart Group. Publisher Copyright: © 2021 Lethaia Foundation. Published by John Wiley & Sons Ltd

PY - 2022

Y1 - 2022

N2 - The Kap Stewart Group (Rhaetian-Sinemurian, Triassic–Early Jurassic) of the Jameson Land Basin in central East Greenland has traditionally been regarded as a strictly continental unit with delta and perennial lake sediments. New finds of plesiosaur bone remain in a thin storm deposited sandstone bed in the middle part of the Rhætelv Formation of the Kap Stewart Group, however, indicates a likely period of marine influence. At the study area at the eastern margin of the basin, the Rhætelv Formation is 300-m thick and overlies unconformably the Norian Fleming Fjord Group. The bone-bearing sandstone occurs 190 m above the base of the group and is closely associated with black laminated mudstones; palynological investigation of three samples from these mudstones indicates that they are of a younger Hettangian age. The Hettangian was a relatively short stage (201.3–199.5 Ma) and elsewhere characterized by two episodes of sea-level highstands. Assuming that the marine incursion in the Jameson land Basin evidenced by the plesiosaur fossil remains took place during the youngest of these sea-level highstands, the bone-bearing bed of the Rhætelv Formation can be dated to 200 Ma and thereby gives the first numerical age constraint of this hitherto poorly dated succession.

AB - The Kap Stewart Group (Rhaetian-Sinemurian, Triassic–Early Jurassic) of the Jameson Land Basin in central East Greenland has traditionally been regarded as a strictly continental unit with delta and perennial lake sediments. New finds of plesiosaur bone remain in a thin storm deposited sandstone bed in the middle part of the Rhætelv Formation of the Kap Stewart Group, however, indicates a likely period of marine influence. At the study area at the eastern margin of the basin, the Rhætelv Formation is 300-m thick and overlies unconformably the Norian Fleming Fjord Group. The bone-bearing sandstone occurs 190 m above the base of the group and is closely associated with black laminated mudstones; palynological investigation of three samples from these mudstones indicates that they are of a younger Hettangian age. The Hettangian was a relatively short stage (201.3–199.5 Ma) and elsewhere characterized by two episodes of sea-level highstands. Assuming that the marine incursion in the Jameson land Basin evidenced by the plesiosaur fossil remains took place during the youngest of these sea-level highstands, the bone-bearing bed of the Rhætelv Formation can be dated to 200 Ma and thereby gives the first numerical age constraint of this hitherto poorly dated succession.

KW - Hettangian

KW - Jameson Land Basin

KW - Kap Stewart Group

KW - marine incursion

KW - plesiosaur

U2 - 10.1111/let.12449

DO - 10.1111/let.12449

M3 - Journal article

AN - SCOPUS:85116774797

VL - 55

JO - Lethaia: An International Journal of Palaeontology and Stratigraphy

JF - Lethaia: An International Journal of Palaeontology and Stratigraphy

SN - 0024-1164

IS - 1

ER -