Recent Research into the Geomorphic History of Lake Michigan Coastal Dunes. Edward Hansen Hope College Special Acknowledgments To: Alan Arbogast Michigan State University Tim Fisher University of Toledo Walter Loope United States Geological Survey Todd Thompson Indiana Geological Survey & Indiana University n a ig h ic e M k a L COASTAL DUNE COMPLEXES StStrand ra n d Plain Pl a i n PrePredominantly d o m i n a n High t ly PePerched r c h e dDunes PrePredominantly d o m i n a nLow t ly LaPerched ke Pl aDunes i n 50 km Michigan In d ia na Lake Michigan Dune Histories Based on: Maps of and Radiocarbon Geomorphic Ages from Position Dune Paleosols Optically Stimulated Sediment Luminescence Cores From Below Dune Dune Lakes Surfaces Reconstructing Dune Histories Using Geomorphic Position Reconstructing Dune Histories Using Maps of and Radiocarbon Ages from Dune Paleosols 30 45 Numbers are calibrated 45 Radiocarbon ages in Years Before Present 30 (YBP). 490 - 290 510 - 290 1720 - 1540 28 15 0 - 0 1930 -1740 2350 - 2150 940 - 750 200 Meters Contour Interval 3 meters Paleo-contours Reconstructing Dune Histories Using Optically Stimulated Luminescence Ages from Beneath Dune Surfaces 2,520-1,980 years shfd033083 P.J. Hoffmaster State Park 2,160-1,440 years shfd033084 shfd030079 shfd030080 shfd030083 3,160 – 2440 years shfd05056 3,000 – 2320 years shfd05057 shfd030084 shfd05056 shfd05057 3,340 – 3,210 – 2.270 years 2,500 years shfd030080 shfd030079 Reconstructing Dune Histories Using Lake Cores From Inland Dune Lakes Sediment Cores From Gilligan Lake in the Coastal Dune Complex southwest of Holland Legend Warren Dunes 11930-9050 years shfd05061 Map from Tague (1946) History of Coastal Dune Complex near Holland, MI I. II. Formation of relatively low dunes over broad Initiation of dune growth during coastal zone during rise to and fall from Nipissing Transgression ~ 5,500 YBP Nipissing peak lake levels ~5500 – 4,000 YBP III. IV. Reworking of near shore dunes into massive Prolonged period of dune stability ~ 2000 parabolic dunes ~3,3000 – 2,000 YBP – 500 YBP Renewed Dune Mobility ~500 – 0 YBP Low Lake Levels: High Lake Levels: Perched Dunes Stable Perched Dunes Mobile From Anderton and Loope (1995) Lake plain complex near Silver Lake, Mi Baedke & Thompson Lake Level Curve Percent Sand in Core From Silver Lake 178 m 177 m 20% 176 m 10% 500 1000 1500 2000 2500 3000 3500 4000 Calendar Years BP Modified from Fisher and Loope (2005) Chronological Data For Coastal Dune Complex Near Holland, Michigan Period of dune mobility indicated by peak in sand concentration in small lakes within dune complex. Lake level curve for Lake Michigan (form Baedke and Thompson, 2000) Low-Perched Coastal Dune Complexes Holland Style Hoffmaster Style (Simple Complex) (Compound Complex) One set of massive Several generations of overlapping and parabolic dunes nested massive parabolic dunes. No high High coastal dune coastal ridge dune ridge Simple Low Perched Dune Complexes Soils formed on the depositional lobes of parabolic dunes are now exposed along the lakeshore, implying net shoreline recession. 40 Modern LEG EN D 30 320 - 60 Up p e r En t iso l Se ri e s 550 - 300 Inceptisol 20 (Holland Geosol) Lowe r Entisol Serie s 2720 - 2330 Ba sa l So i l 10 Ra d io c a rb o n Ag e (Caibrated YBP) 4300 - 3900 Da tum = Lake Michiga n la ke level (176.4 meters above sea level) La ke M i c h i g a n 20 meters Contour Interva l 2 meters net sediment loss > net sediment supply High Perched Dunes Also Form in Areas of Net Negative Sediment Budget and Retreating Shorelines Photo Courtesy of Walter Loope Compound Lake Plain Complex At Hoffmaster State Park, South of Muskegon, Michigan 40 H e i A g Foredunes Coastal Ridge 2 Coastal Ridge 1 B h 30 t ( m e t 20 e r s ) 10 0 0 20 40 60 80 100 120 140 Distance (meters) OSL Ages H e i 710 + /- 160 YBP g 20 h t 960 + /- 280 YBP ( m 10 e 880 + /- 240 YBP t e 0 r s ) 0 40 80 120 160 Dista nc e (m e ters) Fragments of Earlier High Coastal Dune Ridges OSL Ages H e i 710 + /- 160 YBP g 20 h t 960 + /- 280 YBP ( m 10 e 880 + /- 240 YBP t e 0 r s ) 0 40 80 120 160 Distance (meters) Olson (1958) showed that high coastal dune ridges formed by coalescence of successive generations of foredunes. Implication the shoreline at Hoffmaster has been moving lakeward. net sediment loss < net sediment supply Strand plain dune complexes also form in areas of net positive sediment budget and prograding shorelines Conclusions I. Coastal dune complexes along the eastern coast of Lake Michigan were largely formed after the Nipissing transgression. II. High perched dune complexes and simple low- perched dune complexes formed in areas of net negative sediment budget and shore line recession. III. Strand-plain dune complexes and complex low- perched dune complexes formed in areas of net positive sediment budget and shore line progradation. IV. Periods of dune growth and migration tend to correlate with higher lake levels, but lake level does not account for an extensive period of dune stability. .