Radiolaria and late Tertiary and Quaternary history of Antarctic seas1

2013 ◽  
pp. 125-184 ◽  
Author(s):  
James D. Hays
Keyword(s):  
Late Tertiary ◽  
History Of ◽  
Quaternary History

Late Quaternary history of colluvial deposition and erosion in hollows, central California Coast Ranges

1990 ◽  
Vol 102 (7) ◽  
pp. 969-982 ◽  
Author(s):  
STEVEN L. RENEAU ◽  
WILLIAM E. DIETRICH ◽  
DOUGLAS J. DONAHUE ◽  
A. J. TIMOTHY JULL ◽  
MEYER RUBIN
Keyword(s):  
Late Quaternary ◽  
California Coast ◽  
Central California ◽  
History Of ◽  
Quaternary History ◽  
Coast Ranges ◽  
California Coast Ranges

Emplacement ages and exhumation rates for intrusion-hosted Cu–Mo–Sb–Au mineral systems at Freegold Mountain (Yukon, Canada): assessment from U–Pb, Ar–Ar, and (U–Th)/He geochronometers

2012 ◽  
Vol 49 (5) ◽  
pp. 653-670 ◽  
Author(s):  
Thierry Bineli Betsi ◽  
David Lentz ◽  
Brent McInnes ◽  
Noreen J. Evans
Keyword(s):  
Hydrothermal Systems ◽  
Mountain Area ◽  
Erosion Rates ◽  
Late Tertiary ◽  
History Of ◽  
Fast Cooling ◽  
Exhumation Rates ◽  
Uplift And Erosion ◽  
Combined Data ◽  
Hydrothermal Event

To decipher the thermal history of mineralized systems across the Freegold Mountain area (Yukon, Canada), a combined geochronology (zircon U–Pb and hornblende, biotite, and whole rock Ar–Ar) and thermochronology (apatite and zircon (U–Th)/He) study was carried out. Previous U–Pb data combined with new U–Pb and Ar–Ar data show that intrusive bodies across the Freegold Mountain were emplaced during two protracted episodes, the first spanning from 109.6 to 98 Ma and the second between 79 and 68 Ma. Overprinting of the first intrusive event by a second magmatic hydrothermal event is suggested by a zircon U–Pb age of 108.7 ± 0.4 Ma for a chlorite-altered dyke and a whole rock Ar–Ar plateau age of 76.25 ± 0.53 Ma. Zircon (U–Th)/He data are between 66 and 89 Ma, whereas apatite (U–Th)/He data are scattered (38.7–109.9 Ma) and bracket the two magmatic emplacement events. Our combined data reveal a complex history of reheating that led to resetting of numerous chronometers. In most of the investigated magmatic hydrothermal systems, early fast cooling from igneous emplacement through hydrothermal alteration (between 900 and 200 °C) was followed by later and slower cooling accompanying post mineralization uplift and erosion (between 200 and 70 °C). Preliminary models indicate intrusive bodies associated with the Stoddart Cu–Mo ± W prospect cooled slowly (23 °C/Ma) compared with the ones spatially associated with the Revenue Au–Cu prospect (43 °C/Ma), and the similarity of the zircon U–Pb and (U–Th)/He ages from Revenue dyke further supports a rapid cooling from 700 to 180 °C. Erosion rates of 0.035–0.045 mm/year are consistent with tectonic quiescence during the Late Tertiary combined with the lack of Pleistocene glaciation in central Yukon. Such low rates of exhumation favour the formation and preservation of supergene mineralization, such as that found north of Freegold Mountain.

scholarly journals Late Tertiary Geologic History of the Continental Shelf off Northwestern Palawan, Philippines

1973 ◽  
Vol 6 ◽  
pp. 165-176 ◽  
Author(s):  
E.V. Tamesis ◽  
◽  
E.V. Manalac ◽  
C.A. Reyes ◽  
L.M. Ote
Keyword(s):  
Continental Shelf ◽  
Geologic History ◽  
Late Tertiary ◽  
History Of

scholarly journals Plio-Quaternary history of the Turkish coastal zone of the Enez-Evros Delta: NE Aegean Sea

2001 ◽  
Vol 2 (2) ◽  
pp. 95 ◽  
Author(s):  
B. ALPAR
Keyword(s):  
Late Pleistocene ◽  
Sand Dunes ◽  
Aegean Sea ◽  
Interglacial Period ◽  
Shelf Area ◽  
Sea Level Changes ◽  
Seismic Profiles ◽  
Alluvial Deposits ◽  
History Of ◽  
Quaternary History

The Enez-Evros Delta, NE Aegean Sea, is located in one the most important wetlands in the world with its sandy offshore islands, abandoned channel mouths, sand-dunes, shoals, marshlands, saline lagoons and saltpans. It comprises very well developed sedimentary units and a prodelta lying on an older submarine delta. The present day elevations of the middle-late Pleistocene marine terraces indicate a regional tectonic uplift in the area. Due to lack of geophysical and bore hole data and partly due to its strategic position, the structural and stratigraphic features of the submarine extension of the delta are not known in detail. In this paper, Plio-Quaternary history of this delta and its submarine part on the Turkish shelf was explored by using high-resolution shallow reflection seismic profiles. The delta is formed by the alluvial deposits of the Enez-Evros River and shaped by their interaction with the sea. It takes place in front of a large and protected ancient bay which was filled rapidly over millennia. The sediments in the plateau off the river are principally pro-deltaic with muddy areas near the river mouths changing to muddy sand further out. The sea-level changes in Plio-Quaternary were characterised by three different seismic stratigraphic units on the folded Miocene limestone basement. In the late Pleistocene, the shelf area over an Upper Miocene basement was flooded during the Riss-Würm interglacial period, exposed in the Würm glacial stage, and flooded once again during the Holocene transgression.

The Quaternary: History of an Ice Age

2012 ◽  
pp. 409-428 ◽  
Author(s):  
P. L. Gibbard ◽  
N. H. Woodcock
Keyword(s):  
Ice Age ◽  
History Of ◽  
Quaternary History
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