Geology Students, Austin Nijhuis and Jonathan Marshak, Present Posters at GSA

Jonathan MasharkSenior geology student, Austin Nijhuis and junior geology student, Jonathan Marshak, each presented a poster at the GSA Conference recenlty held in New Orleans, LA.

The tilte of Jonathan's presentation was, "Grain size of crevasse-splay deposits in the Mississippi Delta: Implications for coastal restoration." His presentation showed that a crevasse splay of Bayou Lafourche (a former course of the Mississippi River) formed in a cypress swamp is composed of dominant silt, similar to the sediment texture of the Mississippi River load. Therefore, this crevasse splay must have trapped a significant amount of the Bayou Lafourche sediment load, i.e., relatively high sediment trapping efficiency.

Austin NijhuisThe title of Austin's presentation was, "Sediment accretion rates of crevasse-splay deposits in the Mississippi Delta determined by optically-stimulated luminescence dating: Implications for coastal restoration." This presentation showed, through optically-stimulated luminescence dating, that sediment accretion rate of the same crevasse-splay can be >2 cm/yr, a rate that is large enough to keep wetland accretion up with relative sea-level rise in the Mississippi Delta. The relatively high sediment accretion rate is in accordance with the inferred high sediment trapping efficiency of Jonathan Marshak's work.

In their presentations, they used crevasse splays as natural analog of river diversion, artificially reconnecting Mississippi River with its surrounding disappearing wetlands, for coastal restoration and highlighted that river diversions should consider locations like inland swamps which have potentially high sediment trapping efficiency so that the Mississippi River sediment load can be efficiently used for wetland creation.

Austin and Jon are undergraduate research students with the Quaternary Research Group, under the guidance of Professor Torbjörn Törnqvist, Dr. Zhixiong Shen, and lab technician, Jennifer Kuykendall.

101 Blessey Hall, New Orleans, LA 70118, 504-865-5198