scholarly journals Late Mesozoic and early Cenozoic history of central Utah

1946 ◽  
Author(s):  
E.M. Spieker
Keyword(s):  
Late Mesozoic ◽  
History Of ◽  
Early Cenozoic

A late Mesozoic – early Cenozoic sedimentary recycling system on the Gondwana rifted margin of southeast Africa

2020 ◽  
Vol 123 (3) ◽  
pp. 343-356
Author(s):  
T. Andersen ◽  
G.A. Botha ◽  
M.A. Elburg
Keyword(s):  
South Africa ◽  
Detrital Zircon ◽  
Distribution Patterns ◽  
Detrital Zircons ◽  
Late Mesozoic ◽  
Mixing Regime ◽  
History Of ◽  
Gondwana Supercontinent ◽  
Rifted Margin ◽  
Early Cenozoic

Abstract Detrital zircons in late Cretaceous – Palaeogene, calcareous sandstone and conglomerate deposited in continental basins on the southeastern African margin after the breakup of Gondwana have characteristic combinations of age and epsilon-Hf that indicate an origin by recycling of Palaeoproterozoic (Waterberg, Soutpansberg and Pretoria groups) and Phanerozoic (Karoo Supergroup) cover successions. The latter is dominant in the south and east (Boane, Mahosi, Chilojo Cliffs), and the Palaeoproterozoic sources in the northwest (Pafuri, Wright’s Tower, Masisi). This recycling and mixing regime was restricted to late Mesozoic and Palaeogene time in northeastern South Africa and adjoining parts of Mozambique and Zimbabwe. Detrital zircon distribution patterns in these deposits reflect the denudation history of the southern African continental surface after breakup of the Gondwana supercontinent.

Late Mesozoic–Early Cenozoic deformation history of the Yuanma Basin, central South China

2012 ◽  
Vol 570-571 ◽  
pp. 163-183 ◽  
Author(s):  
Li Jianhua ◽  
Zhang Yueqiao ◽  
Dong Shuwen ◽  
Li Hailong
Keyword(s):  
South China ◽  
Deformation History ◽  
Late Mesozoic ◽  
History Of ◽  
Central South ◽  
Early Cenozoic

Late Mesozoic and Cenozoic tectonic history of south central California

Tectonics ◽  
1984 ◽  
Vol 3 (6) ◽  
pp. 659-675 ◽  
Author(s):  
A. E. J. Engel ◽  
P. A. Schultejann
Keyword(s):  
Central California ◽  
Late Mesozoic ◽  
Tectonic History ◽  
South Central ◽  
History Of

scholarly journals Climatic shifts drove major contractions in avian latitudinal distributions throughout the Cenozoic

2019 ◽  
Vol 116 (26) ◽  
pp. 12895-12900 ◽  
Author(s):  
Erin E. Saupe ◽  
Alexander Farnsworth ◽  
Daniel J. Lunt ◽  
Navjit Sagoo ◽  
Karen V. Pham ◽  
...  
Keyword(s):  
Ecological Niche Modeling ◽  
Suitable Habitat ◽  
Coarse Scale ◽  
Climate Variable ◽  
Biogeographic History ◽  
Stem Lineage ◽  
History Of ◽  
Geographic Distributions ◽  
The Tropics ◽  
Early Cenozoic

Many higher level avian clades are restricted to Earth’s lower latitudes, leading to historical biogeographic reconstructions favoring a Gondwanan origin of crown birds and numerous deep subclades. However, several such “tropical-restricted” clades (TRCs) are represented by stem-lineage fossils well outside the ranges of their closest living relatives, often on northern continents. To assess the drivers of these geographic disjunctions, we combined ecological niche modeling, paleoclimate models, and the early Cenozoic fossil record to examine the influence of climatic change on avian geographic distributions over the last ∼56 million years. By modeling the distribution of suitable habitable area through time, we illustrate that most Paleogene fossil-bearing localities would have been suitable for occupancy by extant TRC representatives when their stem-lineage fossils were deposited. Potentially suitable habitat for these TRCs is inferred to have become progressively restricted toward the tropics throughout the Cenozoic, culminating in relatively narrow circumtropical distributions in the present day. Our results are consistent with coarse-scale niche conservatism at the clade level and support a scenario whereby climate change over geological timescales has largely dictated the geographic distributions of many major avian clades. The distinctive modern bias toward high avian diversity at tropical latitudes for most hierarchical taxonomic levels may therefore represent a relatively recent phenomenon, overprinting a complex biogeographic history of dramatic geographic range shifts driven by Earth’s changing climate, variable persistence, and intercontinental dispersal. Earth’s current climatic trajectory portends a return to a megathermal state, which may dramatically influence the geographic distributions of many range-restricted extant clades.

Early Cenozoic resetting of potassium–argon dates and geothermal history of north Okanagan area, British Columbia

1981 ◽  
Vol 18 (8) ◽  
pp. 1310-1319 ◽  
Author(s):  
Wm. H. Mathews
Keyword(s):  
Vitrinite Reflectance ◽  
Volcanic Rocks ◽  
Blocking Temperature ◽  
Low Grade ◽  
High Grade ◽  
Basement Rocks ◽  
Thermal Changes ◽  
History Of ◽  
The Trinity ◽  
Early Cenozoic

Unmetamorphosed Early Eocene sediments and volcanic rocks of the Trinity Hills and Enderby Cliffs yield K–Ar dates of 42–49 Ma. These overlie high-grade gneisses yielding K–Ar ages on biotites, muscovites, and hornblende ranging from 47 to 60 Ma. The Eocene sediments and volcanics rest nearby on low-grade phyllites, greenstones, and schists yielding dates from 83 to 155 Ma. The gneiss dates are regarded as reset by some Late Cretaceous to earliest Cenozoic thermal event that did not affect, at least to the same degree, the nearby less metamorphosed basement rocks. A thermal history has been constructed to account for the decreasing apparent ages of biotite (assumed blocking temperature of 250 °C) with increasing depth below the sub-Eocene unconformity, for the greater ages of hornblende and muscovite in the same rocks (blocking temperatures of 500 and 350 °C), as well as for thermal changes associated with high vitrinite reflectance from coal at one site in the covering sediments. Very rapid stripping (something like 5 km in 12 Ma) is inferred for the areas of reset gneisses, but not for the schist areas, in early Cenozoic time.

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