Determining the Extent of Hothouse Climate Effects on the Jurassic Silica Cycle
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Ohio University / OhioLINK
2017
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1493757729025098 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-ohiou14937577290250982021-08-03T07:02:19Z Determining the Extent of Hothouse Climate Effects on the Jurassic Silica Cycle Starkey, Sarah K. Geology Jurassic chert silica radiolarian A global assessment of the spatial and temporal distribution of Jurassic bedded and nodular cherts undertaken in this study reveals significant findings related to the Jurassic silica cycle. Results show that the earliest Jurassic cherts were mostly deposited in shelf and peritidal settings. This finding challenges the conventional thinking that most Jurassic cherts originated in deep water settings. The Central Atlantic Magmatic Province (CAMP) Large Igneous Provice (LIP) is interpreted to be the source of sufficient silica to the oceans to generate shelf and peritidal chert deposits, just after the end-Triassic extinction. The Pleinsbachian-Toarcian HEATT (Haline Euxinic Acidic Thermal Transgression) episode caused in part by the Karoo-Ferrar LIP led to a relative increase in shelf-originated chert deposits compared to previous periods. Radiolarian cherts were more abundant than expected during HEATT conditions. The low radiolarian diversity at this time shows that some radiolarian taxa could thrive as opportunists and extract significant amounts of dissolved silica from the Early Jurassic ocean. Increased chert deposition during the Late Jurassic is coincident with three sea- floor LIPs that emitted a combined basalt volume nearly equivalent to the Pliensbachian- Toarcian Karoo-Ferrar LIP. The Middle Jurassic and older parts of the Upper Jurassic (Oxfordian-Kimmeridgian) have an increase is chert depsotion without significant LIP activity. The chert dpeosits of Aalenian through Tithonian age might be an indication of the increasing influence of diatoms on the Jurassic silica cycle. 2017-09-20 English text Ohio University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1493757729025098 http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1493757729025098 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Geology Jurassic chert silica radiolarian |
| spellingShingle |
Geology Jurassic chert silica radiolarian Starkey, Sarah K. Determining the Extent of Hothouse Climate Effects on the Jurassic Silica Cycle |
| author |
Starkey, Sarah K. |
| author_facet |
Starkey, Sarah K. |
| author_sort |
Starkey, Sarah K. |
| title |
Determining the Extent of Hothouse Climate Effects on the Jurassic Silica Cycle |
| title_short |
Determining the Extent of Hothouse Climate Effects on the Jurassic Silica Cycle |
| title_full |
Determining the Extent of Hothouse Climate Effects on the Jurassic Silica Cycle |
| title_fullStr |
Determining the Extent of Hothouse Climate Effects on the Jurassic Silica Cycle |
| title_full_unstemmed |
Determining the Extent of Hothouse Climate Effects on the Jurassic Silica Cycle |
| title_sort |
determining the extent of hothouse climate effects on the jurassic silica cycle |
| publisher |
Ohio University / OhioLINK |
| publishDate |
2017 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1493757729025098 |
| work_keys_str_mv |
AT starkeysarahk determiningtheextentofhothouseclimateeffectsonthejurassicsilicacycle |
| _version_ |
1719452214290808832 |