Provenance controls on the Nd-Sr-O isotopic composition of sandstones: Example from Late Mesozoic Great Valley forearc basin, California

1993 ◽  
pp. 121-134 ◽  
Author(s):  
A. M. Linn ◽  
D. J. DePaolo
Keyword(s):  
Isotopic Composition ◽  
Forearc Basin ◽  
Late Mesozoic ◽  
Great Valley

scholarly journals The birth of a forearc: The basal Great Valley Group, California, USA

Geology ◽  
2019 ◽  
Vol 47 (8) ◽  
pp. 757-761 ◽  
Author(s):  
Devon A. Orme ◽  
Kathleen D. Surpless
Keyword(s):  
North America ◽  
Detrital Zircon ◽  
Forearc Basin ◽  
Early Stages ◽  
Structural Style ◽  
Basin Development ◽  
Great Valley Group ◽  
Extensional Model ◽  
Great Valley

AbstractThe Great Valley basin of California (USA) is an archetypal forearc basin, yet the timing, structural style, and location of basin development remain controversial. Eighteen of 20 detrital zircon samples (3711 new U-Pb ages) from basal strata of the Great Valley forearc basin contain Cretaceous grains, with nine samples yielding statistically robust Cretaceous maximum depositional ages (MDAs), two with MDAs that overlap the Jurassic-Cretaceous boundary, suggesting earliest Cretaceous deposition, and nine with Jurassic MDAs consistent with latest Jurassic deposition. In addition, the pre-Mesozoic age populations of our samples are consistent with central North America sources and do not require a southern provenance. We interpret that diachronous initiation of sedimentation reflects the growth of isolated depocenters, consistent with an extensional model for the early stages of forearc basin development.

Isotopic Compositions of Selected Ore Leads from Northeastern Washington

1973 ◽  
Vol 10 (5) ◽  
pp. 670-678 ◽  
Author(s):  
W. D. Small
Keyword(s):  
Isotopic Composition ◽  
Lead Isotope ◽  
Isotope Composition ◽  
Canadian Cordillera ◽  
Basement Structure ◽  
Late Mesozoic ◽  
Sedimentary Structures ◽  
Lead Isotope Composition ◽  
Isotopic Abundances ◽  
Primary Type

Isotopic composition of ore leads from four districts in northeastern Washington has been measured with a precision in the ratios of about 0.1‰. Results indicate that the mineralization in the Marshall Diorites of Pend Oreille County is by a primary type lead with a model age of about 1300 to 1500 m.y. The remainder of the measured leads from Pend Oreille and Stevens Counties have a radiogenic component which could have developed in a closed system during the interval 1370 to about 250 m.y. ago. Leads from Ferry and Okanogan Counties have only slight variations in their isotopic abundances. These latter leads could have been produced by an homogenization of the leads from Pend Oreille and Stevens Counties through the mechanism of a late Mesozoic metamorphism of Mesozoic sedimentary structures in Ferry and Okanogan Counties, these latter sedimentary structures being the products of erosion of rocks in Pend Oreille and Stevens Counties. There is no evidence of an ancient basement structure under Ferry and Okanogan Counties from the data presented herein. The lead isotope composition of the ores from northeastern Washington is compatible with the current concepts of the crustal structure across the Canadian Cordillera.

scholarly journals Mid-Cenozoic succession on the northeast limb of the Mount Diablo anticline, California—A stratigraphic record of tectonic events in the forearc basin

2021 ◽  
Author(s):  
Raymond Sullivan ◽  
Morgan D. Sullivan ◽  
Stephen W. Edwards ◽  
Andrei M. Sarna-Wojcicki ◽  
Rebecca A. Hackworth ◽  
...  
Keyword(s):  
North America ◽  
Late Miocene ◽  
Plate Boundary ◽  
Leading Edge ◽  
Late Eocene ◽  
Late Cenozoic ◽  
Forearc Basin ◽  
Late Mesozoic ◽  
The North ◽  
Silicic Volcanic

ABSTRACT The mid-Cenozoic succession in the northeast limb of the Mount Diablo anticline records the evolution of plate interactions at the leading edge of the North America plate. Subduction of the Kula plate and later Farallon plate beneath the North America plate created a marine forearc basin that existed from late Mesozoic to mid-Cenozoic times. In the early Cenozoic, extension on north-south faults formed a graben depocenter on the west side of the basin. Deposition of the Markley Formation of middle to late? Eocene age took place in the late stages of the marine forearc basin. In the Oligocene, the marine forearc basin changed to a primarily nonmarine basin, and the depocenter of the basin shifted eastward of the Midland fault to a south-central location for the remainder of the Cenozoic. The causes of these changes may have included slowing in the rate of subduction, resulting in slowing subsidence, and they might also have been related to the initiation of transform motion far to the south. Two unconformities in the mid-Cenozoic succession record the changing events on the plate boundary. The first hiatus is between the Markley Formation and the overlying Kirker Formation of Oligocene age. The succession above the unconformity records the widespread appearance of nonmarine rocks and the first abundant appearance of silicic volcanic detritus due to slab rollback, which reversed the northeastward migration of the volcanic arc to a more proximal location. A second regional unconformity separates the Kirker/Valley Springs formations from the overlying Cierbo/Mehrten formations of late Miocene age. This late Miocene unconformity may reflect readjustment of stresses in the North America plate that occurred when subduction was replaced by transform motion at the plate boundary. The Cierbo and Neroly formations above the unconformity contain abundant andesitic detritus due to proto-Cascade volcanism. In the late Cenozoic, the northward-migrating triple junction produced volcanic eruptive centers in the Coast Ranges. Tephra from these local sources produced time markers in the late Cenozoic succession.

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