PGS: Holocene-Anthropocene Transition in Chesapeake Bay

The May meeting of the Potomac Geophysical Society will be held May 19th Fife and Drum Dining Room at the Fort Myer Officers’ Club in Arlington, VA ( in the Campaign Room.

This month’s talk will be: The Holocene-Anthropocene Transition in Chesapeake Bay by George R. Helz, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD.


Fifteen chalcophile elements in the deep channel sediments of Chesapeake Bayall became markedly enriched relative to crustal abundances during the 20th century. Excess (above crustal) concentrations for most elements are highly correlated, suggesting control by a single process.  This is a surprising result because industrial and commercial uses of these elements differ greatly.  Anthropogenic sources therefore would be expected to be independent of one another.  After 1940, concentrations of these elements in sediments are cyclic (~20 y period). A known climate cycle affecting river inflows has a similar period. It is proposed that aerosol deposition on soils has veneered the watershed with a homogenized reservoir of these contaminants. The decade-scale variation in river discharge will vary the mix of contaminated veneer vs, uncontaminated weathering products emerging from the watershed, thus explaining the trace element cycle.  The simultaneous rise in concentrations of all these elements between about 1920 and 1940 must be regional in extent and can be viewed as a chemostratigraphic marker of the Holocene-Anthropocene transition.

Biographical Information:

A.B. Geology, Princeton University, 1964; Ph.D. Geochemistry, Pennsylvania State University, 1971; Chemistry Department Faculty, University of Maryland, 1970-2004; thereafter, Emeritus.  Honors include Distinguished Teacher-Scholar,UniversityofMaryland; Senior Visiting Fellow,Manchester University,U.K.; Fulbright Fellow, Rudjer Boskovic Institute,Croatia; Allen Cox Visiting Professor,StanfordUniversity.

Dinner Menu  

Delicious Selections from the Sea
Atlantic Salmon
Snow Crab Legs
Shrimp & Clams

Raw Bar
Shrimp peel & eat
Oysters on the half shell

Seafood Pasta Station

A scrumptious sauté with your choice of:
Shrimp, Crabmeat, Scallops, Chicken, Fresh Vegetables
Pasta Sauces include Marinara, Alfredo, Garlic Butter

Delicious Selections from the Land

Chef’s choice Carved Meat and/or Chicken Dishes

Buffet includes a Fresh Salad and Soup Bar and an elegant Dessert Bar with assorted cakes and pies.

Reception at 6:30.  Dinner at 7:30.  Talk at 8:30 PM.  Please note that the talk starts earlier than the usual time. Allow 15 minutes for security entering Ft. Myer as all civilian vehicles are searched.  To ensure access to and from Fort Myer use the Hatfield Gate, open 24 hours a day (  If you wish to attend dinner ($30), please make reservations with Joydeep Bhattacharyya at 571-269-8432 or via E-mail at  If you wish, please feel free to attend the talk without dinner.  Non-members and guests are welcome.  Visit the PGS web site at for new meeting announcements, etc.  Please send changes of address or email to


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