K-Ar Geochronology Results for the Mount Pisgah Quadrangle, Utah

This Open-File Report makes available raw analytical data from laboratory procedures completed to determine the age of a rock sample collected during geologic investigations funded or partially supported by the Utah Geological Survey (UGS). Table 1 provides the sample identification and location for the age data. The references listed in table 1 generally provide additional information such as sample location, geologic setting, and significance or interpretation of the sample in the context of the area where it was collected. This report was prepared by Krueger Enterprises, Inc., Geochron Laboratories Division in 1995 under contract to the UGS. These data are highly technical in nature and proper interpretation requires considerable training in the applicable geochronologic techniques.

Crandallite-rich beds of the Libkovice Member, Most Basin, Czech Republic: climatic extremes or paleogeographic changes at the onset of the Miocene Climatic Optimum?

We describe the occurrence and possible origin of rare beds 1–10cm thick and containing 20–70% of crandallite, a Ca-Al phosphate enriched in Sr and Ba, found within otherwise monotonous clay-rich lacustrine sediments of the Most Basin in the Central-European Neogene Ohře Rift system. The beds were formed at ca. 17.31, 17.06, and 16.88Ma, while the entire suite of monotonous clays of the Libkovice Member was deposited between 17.46 and 16.65Ma. Trace-element and organic geochemistry, Ar-Ar geochronology and C-O-Sr isotope systematics are used to infer their source and processes leading to their formation. The most enigmatic aspect of the formation of the crandallite beds is the removal of a huge amount of phosphorus from its biogenic cycle in the lacustrine system, which was otherwise stable for ca. 0.8My. Formation of detritus-poor crandallite beds could result from some exceptional environmental disruptions that hindered transport of fine clastic material to the basin floor. Silicic volcanic activity in the area of the Pannonian Basin could have triggered this disruption. Crandallite could provide evidence of long-lasting droughts and acidification of the exogenic environment, as they are roughly coeval with the onset of the Miocene Climatic Optimum at ca. 17.0Ma.

Supplemental Material: Evolution of the Late Cretaceous Nanaimo Basin, British Columbia, Canada: Definitive provenance links to northern latitudes

<div>Item A: Summary of Nanaimo Group Detrital Zircon Samples (A1-A2). Item B: Biostratigraphic Age Control on Samples (B1-B10). Item C: Nanaimo Group Detrital Zircon Data (C1-C77). Item D: Nanaimo Group Conglomerate Clast Detrital Zircon Data (D1-D7). Item E: Nanaimo Group Muscovite Ar-Ar Geochronology (E1-E7). Item F: Nanaimo Group Lu-Hf Isotopic Data (F1-F7). Item G: Modern Salmon River Detrital Zircon Data (G1-G3).<br></div>

Supplemental Material: Evolution of the Late Cretaceous Nanaimo Basin, British Columbia, Canada: Definitive provenance links to northern latitudes

<div>Item A: Summary of Nanaimo Group Detrital Zircon Samples (A1-A2). Item B: Biostratigraphic Age Control on Samples (B1-B10). Item C: Nanaimo Group Detrital Zircon Data (C1-C77). Item D: Nanaimo Group Conglomerate Clast Detrital Zircon Data (D1-D7). Item E: Nanaimo Group Muscovite Ar-Ar Geochronology (E1-E7). Item F: Nanaimo Group Lu-Hf Isotopic Data (F1-F7). Item G: Modern Salmon River Detrital Zircon Data (G1-G3).<br></div>

Supplemental Material: Regional chronostratigraphic synthesis of the Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE2) interval, Western Interior Basin (USA): New Re-Os chemostratigraphy and 40Ar/39Ar geochronology

(1) Complete Ar geochronology data, bentonite correlations, and collection in Kaiparowits Plateau, Cenomanian-Turonian boundary age calculations, core photos and description of hiatuses, and Angus Core depth scale alignment correction. (2) Time scale tables for cores.

Fluid inclusion 40Ar/39Ar geochronology of andalusite from syn-tectonic quartz veins: perspectives on dating regional deformation and metamorphism events

&lt;p&gt;A long-lasting orogenic process often generates vast complexity of deformation and metamorphism. Understanding the time scales of these processes is essential for the reconstruction of the finite architecture of a fossil orogenic belt, which, nevertheless, is not always straightforward. This is because multiple episodes of tectonic events would lead to multiple growth periods of accessory minerals and deformation of rock-forming minerals, which brings challenges for conventional dating methods such as U&amp;#8211;Pb, K/Ar, and &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar step-heating. Fortunately, the emplacement of syn-tectonic quartz veins witness the deformation process and potentially, the associated metamorphism. They, therefore, have the potential to provide vital age information for regional crustal evolution. These veins, especially those in metapelitic terranes, usually contain andalusite, a fluid inclusion bearing K-poor pure aluminosilicate, which stands a good chance for directly dating syn-tectonic veining events by the fluid inclusion &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar stepwise crushing technique.&lt;/p&gt;&lt;p&gt;Combined with detailed petro-structural investigation, this study applies the fluid inclusion &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar geochronology, for the first time, on andalusite minerals in syn-tectonic quartz veins from the Chinese Altai Orogenic Belt, Central Asia, to explore a new way for dating deformation and metamorphism. &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar stepwise crushing on three andalusite samples yielded well-defined Early Permain ages of 282&amp;#8211;274 Ma. These ages are consistent with previously published emplacement ages of regional syn-tectonic leucosome/pegmatite/granite veins and metamorphic ages for local and region schist/gneiss from the same metamorphic series. These results collectively suggest that the fluid inclusion &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar geochronology of andalusite in syn-tectonic quartz veins has the potential to constrain the timing of fluid-present deformation and potentially contemporaneous metamorphism. This work, therefore, provides a novel way for the age constraints of regional tectonic-thermal evolution of metapelitic terranes in general.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Acknowledgements &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;This project was supported by the Guangdong Basic and Applied Basic Research Foundation (No. 2019A1515012190), the International Partnership Program of Chinese Academy of Sciences (No. 132744KYSB20190039) and the Projects funded by China Postdoctoral Science Foundation (No. 2019M663133). A Guangdong Special Support Program to Y.D. Jiang is also acknowledged.&lt;/p&gt;