scholarly journals Stepwise basin evolution of the Middle Jurassic–Early Cretaceous rift phase in the Central Graben area of Denmark, Germany and The Netherlands

2018 ◽  
Vol 469 (1) ◽  
pp. 305-340 ◽  
Author(s):  
R. M. C. H. Verreussel ◽  
R. Bouroullec ◽  
D. K. Munsterman ◽  
K. Dybkjær ◽  
C. R. Geel ◽  
...  
Keyword(s):  
The Netherlands ◽  
Early Cretaceous ◽  
Middle Jurassic ◽  
Basin Evolution

The Currently Earliest Angiosperm Fruit from the Jurassic of North America

2021 ◽  
Vol 2 (4) ◽  
Author(s):  
Xin Wang
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Middle Jurassic ◽  
Early Evolution ◽  
The North ◽  
Plant Group ◽  
Ecological Radiation ◽  
Origin Of Angiosperms ◽  
Crucial Test

Angiosperms are the single most important plant group in the current ecosystem. However, little is known about the origin and early evolution of angiosperms. Jurassic and earlier traces of angiosperms have been claimed multiple times from Europe and Asia, but reluctance to accept these records remains. To test the truthfulness of these claims, palaeobotanical records from continents other than Europe and Asia constitute a crucial test. Here I document a new angiosperm fruit, Dilcherifructus mexicana gen. et sp. nov, from the Middle Jurassic of Mexico. Its Jurassic age suggests that origin of angiosperms is much earlier than widely accepted, while its occurrence in the North America indicates that angiosperms were already widespread in the Jurassic, although they were still far away from their ecological radiation, which started in the Early Cretaceous.

The provenance of Middle Jurassic sandstones in the Scotian Basin: petrographic evidence of passive margin tectonics 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin. 2Geological Survey of Canada Contribution 20110319.

2012 ◽  
Vol 49 (12) ◽  
pp. 1463-1477 ◽  
Author(s):  
Gang Li ◽  
Georgia Pe-Piper ◽  
David J.W. Piper
Keyword(s):  
Early Cretaceous ◽  
Middle Jurassic ◽  
Mineral Chemistry ◽  
Passive Margin ◽  
Heavy Minerals ◽  
Late Triassic ◽  
Cape Breton Island ◽  
Grand Banks ◽  
Meguma Terrane ◽  
Geomorphological Evolution

The tectonic and geomorphological evolution of the Scotian margin and its hinterland is poorly known between Late Triassic rifting and the Early Cretaceous progradation of major deltas. This study determined sedimentary provenance of Middle Jurassic Mohican Formation sandstones from three wells using heavy minerals and mineral chemistry. Indicator minerals such as xenotime, altered ilmenite, and varietal types of garnet and tourmaline are similar to those in Hauterivian–Barremian sandstones in the western Scotian Basin, which are almost exclusively derived from the Meguma terrane. The wells adjacent to the Canso Ridge have more zircon and less ilmenite, indicating a greater contribution of polycyclic reworking, but with an ultimate source in the Meguma terrane. Zircon and ilmenite were likely derived in part from Carboniferous sandstones in eastern mainland Nova Scotia and Cape Breton Island. Any river drainage from the inboard terranes of the Appalachians either was diverted through the Fundy Basin or entered the easternmost Scotian Basin, where the Mohican Formation is 5.5 km thick, along the linear continuation of the southwest Grand Banks transform. Such sediment did not reach the Canso Ridge, suggesting that the Cobequid–Chedabucto fault zone in Orpheus graben was not a significant physiographic feature. This tectonically controlled paleogeography in the Middle Jurassic is quite different from that during active rifting in the Late Triassic – Early Jurassic. Middle Jurassic quiescence was followed in the Tithonian – Early Cretaceous by renewed tectonic uplift associated with rifting of Grand Banks from Iberia and Labrador from Greenland.

Sign in / Sign up

Export Citation Format

Share Document