Sander Basalt

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Sander Basalt
Stratigraphic range: 201.5 ± 1.3 Ma [1]
Type Rift basin
Unit of Culpeper Basin
Sub-units Sandstone, Siltstone
Underlies Turkey Run Formation
Overlies Waterfall Formation
Thicknessup to 545 metres (1,790 ft) [2]
Lithology
Primary Tholeiitic Basalt
Location
Location Northwestern Virginia
Coordinates 38°45′38″N77°40′48″W / 38.7605°N 77.68°W / 38.7605; -77.68
Region Eastern United States
Country United States
Extent30 miles (48 km)
USA Virginia relief location map.svg
Red pog.svg
Sander Basalt
Sander Basalt

Sander Basalt is the third and final basalt flow in the Culpeper Basin. Located just east of the Appalachian Mountains in northern Virginia, it is part of the larger Central Atlantic Magmatic Province (CAMP) large igneous province, and its associated rift valleys, Newark Supergroup, which was one of the largest volcanic eruptions in Earth's history. [3] It is associated with the initial break up of the ancient supercontinent of Pangea and just before the opening of the Atlantic Ocean. [4]

Contents

Geological history

Location of the Culpeper Basin Culpeper Basin Relief Map.jpg
Location of the Culpeper Basin

The Central Atlantic Magmatic Province was the initial pulse of magmatism associated with the rifting a break up of Pangea. Pangea formed ~330 Ma with the closing of the Rheic Ocean [5] [6] During Pangea's formation, many different island arc (exotic terranes) collided with Laurentia and subsequently formed the Appalachian Mountains. The three mountain-building events that raised the Appalachians were the Taconic, Acadian, and Alleghanian oroganies. [7]

These mountain building events not only raised the Appalachian Mountains to possibly as high as the present day Himalayan Mountains, but the continued accreation of island arc terranes created zones of weakness in the crust. [8] These would be used by magma during the CAMP eruptions as an easy pathway for magma to reach the surface. [9]

Sander Basalt

Sander Basalt was not a single volcanic vent. Instead it was an extremely long fissure eruption that was possibly hundreds of miles long. The Bardarbunga Volcano pictured is the type of eruption Sander basalt would have been, but on a much larger scale Bardarbunga Volcano, September 4 2014 - 15143266611.jpg
Sander Basalt was not a single volcanic vent. Instead it was an extremely long fissure eruption that was possibly hundreds of miles long. The Bárðarbunga Volcano pictured is the type of eruption Sander basalt would have been, but on a much larger scale

The Sander Basalt was the third eruptive event in the Culpeper Basin (with the Mount Zion Church Basalt and Hickory Grove Basalt preceding it.) The eruption was not one continuous eruption for its duration. There is evidence for at least nine different flows; by far the most of the three eruptive pulses (both the Mount Zion Church Basalt and the Hickory Grove Basalt had two flows each). [10] Each individual lava flow is separated by a thin layer of sedimentary layer of sandstone and siltstone.

Sanders Basalt is slightly different than the other two Culpeper Basin basalt flows. It has a distinctive curved columnar joints. It is also has a slightly different chemistory than the other two basalt flows. It is high-titanium, high-iron, quartz-normative Tholeiitic basalts. [11]

References

  1. Gregory Shellnutt, J.; Dostal, Jaroslav; Yeh, Meng-Wan (April 2018). "Mantle source heterogeneity of the Early Jurassic basalt of eastern North America". International Journal of Earth Sciences. 107 (3): 1033–1058. doi:10.1007/s00531-017-1519-0 . Retrieved 30 December 2025.
  2. Lee, K.Y. (1980). "Triassic-Jurassic geology of the southern part of the Culpeper Basin and the Barboursville Basin, Virginia". Pubs USGS. United States Geological Survey. doi:10.3133/ofr80468 . Retrieved 30 December 2025.
  3. Marzoli, Andrea; Callegaro, Sara; Dal Corso, Jacopo; Davies, Joshua H. F. L.; Chiaradia, Massimo; Youbi, Nassrrdine; Bertrand, Hervé; Reisberg, Laurie; Merle, Renaud; Jourdan, Fred (2018). "The Central Atlantic Magmatic Province (CAMP): A Review". The Late Triassic World. 46: 91–125. doi:10.1007/978-3-319-68009-5_4 . Retrieved 30 December 2025.
  4. Davies, Joshua; Marzoli, Andrea; Bertrand, Hervé; Youbi, Nasrrddine; Schaltegger, Urs (April 2015). "Exploring the pre-eruptive history of the Central Atlantic Magmatic Province (CAMP) and the link with the end Triassic extinction using high precision U-Pb zircon and baddeleyite geochronology". EGU General Assembly Conference Abstracts. EGU General Assembly. p. 9479. Retrieved 30 December 2025.
  5. Nance, R. Damian; Gutiérrez-Alonso, Gabriel; Keppie, J. Duncan; Linnemann, Ulf; Murphy, J. Brendan; Quesada, Cecilio; Strachan, Rob A.; Woodcock, Nigel H. (March 2012). "A brief history of the Rheic Ocean". Geoscience Frontiers. 3 (2): 125–135. doi:10.1016/j.gsf.2011.11.008 . Retrieved 30 December 2025.
  6. Nance, R. Damian; Gutiérrez-Alonso, Gabriel; Keppie, J. Duncan; Linnemann, Ulf; Murphy, J. Brendan; Quesada, Cecilio; Strachan, Rob A.; Woodcock, Nigel H. (March 2010). "Evolution of the Rheic Ocean". Gondwana Research. 17 (2–3): 194–222. doi:10.1016/j.gr.2009.08.001 . Retrieved 30 December 2025.
  7. Marzen, Rachel E.; Shillington, Donna J.; Lizarralde, Daniel; Harder, Steven H. (July 2019). "Constraints on Appalachian Orogenesis and Continental Rifting in the Southeastern United States From Wide‐Angle Seismic Data". Journal of Geophysical Research: Solid Earth. 124 (7): 6625–6652. doi:10.1029/2019JB017611.{{cite journal}}: |access-date= requires |url= (help)
  8. Hillenbrand, Ian W.; Williams, Michael L. (1 August 2021). "Paleozoic evolution of crustal thickness and elevation in the northern Appalachian orogen, USA". Geology. 49 (8): 946–951. doi:10.1130/G48705.1 . Retrieved 30 December 2025.
  9. Whalen, Lisa; Gazel, Esteban; Vidito, Christopher; Puffer, John; Bizimis, Michael; Henika, William; Caddick, Mark J. (October 2015). "Supercontinental inheritance and its influence on supercontinental breakup: The C entral A tlantic M agmatic P rovince and the breakup of P angea". Geochemistry, Geophysics, Geosystems. 16 (10): 3532–3554. doi:10.1002/2015GC005885 . Retrieved 30 December 2025.
  10. Tollo, Richard; Gottfrled, David; Froellch, Albert (14 May 1987). "Field Guide to the Igneous Rocks of the Southern Culpeper Basin, Virginia" (PDF). Pubs USGS. United States Geological Survey. Retrieved 31 December 2025.
  11. Weems, Robert; Olsen, Paul (February 1997). "Synthesis and revision of groups within the Newark Supergroup, eastern North America" (PDF). United States Geological Survey. Retrieved 30 December 2025.