State of Indiana Department of Natural Resources GEOLOGICAL SURVEY SCIENTIFIC AND TECHNICAL STAFF OF THE GEOLOGICAL SURVEY JOHN B. PATTON, State Geologist MAURICE E. BIGGS, Assistant State Geologist LEROY E. BI-CKr R, Staff Geologist RICHARD L. POWELL, Staff Geologist MARY BETH FOX, Mineral Statistician COAL SECTION GEOPHYSICS SECTION CHARLES E. WIER, Geologist and Head MAURICE:. E. BIGGS, Geophysicist and Head HAROLD C. HUTCHISON, Geologist ROBERT F. BLAKELY, Geophysicist VA~CI- P. WIRAM, Geologist JOSEPH F. WHALEY, Geophysicist MARVIN T. IVERSO"I, Geological Assistant CLARENCE C. HASKINS, Driller JOHN R. HELMS, Geophysical Assistant DRAFTING AND PHOTOGRAPHY SECTION WILLIAM H. MORAN, Chief Draftsman and Head RICHARDT. HILL, Geological Draftsman INDUSTRIAL MINERALS SECTION ROBI RT E. JUDAH, Geological Artist-Draftsman DONALD D. CARR, Geologist and Head ROGER L. PURCELL, Senior Geological Draftsman CURTIS H. AULT, Geologist GEORGE R. RIJ\GfR, Photographer GEORGES. AUSTIN, Geologist MICHAEL C. MOORE, Geologist EDUCATIONAL SER VICES SECTION R. DEE RARICK, Geologist and Head PETROLEUM SECTION GEOCHEMISTRY SECTION T. A. DAWSON, Geologist and Head R. K. LEININGER, Geochemist and Head G. L. CARPENTER, Geologist LOUIS V. MILLER, Coal Chemist ANDREW J. HREHA, Geologist MARGARET V. GOLDE, Instrumental Analyst STANLEY J. KELLER, Geologist CARRIE F. FOLEY, Geochemical Assistant DAN M. SULLIVAN, Geologist JAMES T. CAZFE, Geological Assistant GEOLOGY SECTION WILLIAM t. HAMM, Geological Assistant ROBERT H. SHAVER, Paleontologist and Head SHERRY SLUSHER, Geological Assistant HENRY H. GRAY, Head Stratigrapher N. K. BLEUER, Glacial Geologist EDWIN J. HARTKF, Environmental Geologist PUBLICA TJONS SECTION JOHN R. HILL, Glacial Geologist GERALD S. WOODARD, Editor and Head CARL B. REXROAD, Paleontologist DONNA C. SCHULTZ, Sales and Records Clerk The Indiana Dunes­ Legacy of Sand By JOHN R. HILL DEPARTMENT OF NATURAL RESOURCES GEOLOGICAL SURVEY SPECIAL REPORT 8 PRINTED BY AUTHORITY OF THE STATE OF INDIANA BLOOMINGTON, INDIANA: 1974 .------------------------- STATE OF INDIANA Otis R. Bowen, Governor DEPARTMENT OF NATURAL RESOURCES Joseph D. Cloud, Director GEOLOGICAL SURVEY John B. Patton, State Geologi.•t For sale by Geological Survey, Bloomington, Ind. 47401 Price 75 cents Contents Page Page Introduction . 1 Vegetative sequences from shore inland . 7 Glacial history . I "Squeaking sand" . 8 Glacial Lake Chicago . 2 Pinhook Bog . 9 Shoreline processes . 3 Summary...... 9 The sand dunes . 7 Glossary . 9 Illustrations Page Plate Map of Dunes area showing generalized geology and numbered localities referred to in text ................................................... Inside back cover Figure Map of glacial Lake Chicago during the Glenwood high water stage . 2 2 Cross section illustrating the three major beaches and corresponding levels of glacial Lake Chicago . 2 3 Oblique waves producing longshore currents at shoreline near Ogden Dunes . 3 4 Sediments borne by longshore currents trapped on the up-current side of the groyne at Michigan City harbor . 4 5 Lake currents undercutting old Lakeshore Drive at Central Avenue near Beverly Shores . 4 6 Beach and over-steepened foredune in the Dunes National Lakeshore near Beverly Shores reduced by strong wave action . 5 7 Foredune with plant cover in the Indiana Dunes State Park . 6 8 Typical blowout in the Dunes area adjacent to the parking lot at the Indiana Dunes State Park. 6 9 Sand knob in West Beach interdunal area protected from wind erosion by its plant cover . 7 IO Migrating sand burying a living forest at West Beach . 8 The Indiana Dunes - Legacy of Sand By JOHN R. HILL Introduction the deposition of glacial debris, lake clays, and beach The area including the Indiana Dunes State Park and sands. However, materials deposited either directly or Dunes National Lakeshore is unique in its diversity of indirectly by the Wisconsinan ice sheet are abundant geologic features and terrain. The forces of glaciers, throughout the state and federal parks. wind, and water have combined over the eons to The actively advancing Wisconsinan continental create picturesque morainal topography, a vast fresh glacier moved vast amounts of debris by carrying water lake, great expanses of sand in the form of boulders, gravel, silt, sand, and clay within, beneath, beaches and dunes, and bogs containing exotic plant and on top of its frozen mass. As this glacier waxed species. Soon to be completely surrounded by an ever­ and waned, the mixture of unsorted debris was de­ expanding urban-industrial complex, the dunes area posited by the ice as till in the form of ground and will remain as a lasting monument to the complexity end moraines. The Valparaiso Moraine, a massive, and beauty of nature. arcuate end moraine, which extends around the southern perimeter of Lake Michigan, is one of the Glacial History most impressive glacial features in northwestern The park area, as well as all northern Indiana, was Indiana (area 5, pl. I). At its highest point, near subjected to four major glaciations during the Pleisto­ Valparaiso, the moraine is more than 800 feet above cene Epoch, that is, during the past million years. sea level, rising 200 feet above Lake Michigan to the Listed below are the names of these major ice north and more than 150 feet above the Kankakee advances and the duration of each. The Dunes area flood plain to the south. The Valparaiso Moraine, is situated on deposits associated with the last glacia­ which lies entirely beyond the boundaries of the two tion, the Wisconsinan. Deposits left by the earlier parks except at Pinhook Bog (area 6. pl. I), serves as glaciers are not found surficially in the Dunes area a major divide separating drainage northward to Lake because they were either buried under the Wiscon­ Michigan from drainage southward to the Kankakee sinan drift (see glossary for definition of italicized River. Till deposited before the formation of the terms) or stripped away by the Wisconsinan ice sheet. Valparaiso Moraine is in the form of flat-lying ground moraine (area 4, pl. 1) and is associated with an earlier Approximate age Glaciation Interglaciation (in years) advance of the Wisconsinan glacier. As the Wisconsinan ice sheet retreated northward, Recent 5,000 - 70,000 Wisconsinan large volumes of meltwater that were produced car­ Sangamonian ried off the ice-borne sand and gravel and deposited it 300,000 Illinoian Yarmouthian as outwash. Outwash deposits reworked by wind and 700,000 Kansan water are visible throughout the Dunes area in the Aftonian 1,000,000 Nebraskan form of sand dunes and beaches and, in the West Beach area (area 7, pl. I), as gravel deposits partially covered by sand. Between glacial advances there were periods of Silt and clay, absent from the outwash deposits, relative climatic warming, during which the glaciers were laid down as lake sediments. Mud carried in retreated northward. Forests, prairies, and swamps suspension by glacial rneltwaters was deposited in developed atop the glacial debris of the previous ice standing water where rapidly flowing glacial streams advance. Materials, such as soils, formed during the bearing these materials came to rest. Lake, pond, and interglacial periods are not visible in the park area swamp deposits of the type just described can be seen either because they were destroyed by the advancing in the federal park (area 8, pl. 1), as well as south of Wisconsinan ice sheet or because they were buried by the state park (pl. I). 1 2 THE INDIANA DUNES-LEGACY OF SAND WISCONSIN ' "'"---\ --- MICHIGAN Present lake Michigan } shoreline (580 ft.) ( Mic°hi;°an City -- i---- -- drainage 0 Valparaiso I K' OHIO Glenwood Shore of I Lake Chicago 1640 ft.I ~~~~~~~~~~~-----< I EXPLANATION I INDIANA ILLINOIS - Wisconsinan glacier I ~ Present lake Michigan Glenwood stage of Lake Chicago 0 100 Miles - Figure I. Map of glacial Lake Chicago during the Glenwood high water stage. Glacial Lake Chicago sea level, but the shore of present-day Lake Michigan Lake Michigan, the third largest of the Great Lakes is only 580 feet above sea level. What happened to and the sixth largest lake in the world, came into lower the Jake to its present level? With the final existence about 2,000 years ago at the close of the retreat of the glaciers, Lake Chicago remained as an last major glaciation, the Wisconsinan. Ancestral Lake enormous fresh water body, brim full to overflowing. Michigan (glacial Lake Chicago), from which Lake The Valparaiso Moraine, the U-shaped earthen dike Michigan formed, had much the same shape as deposited by a lobe of the Wisconsinan glacier, was present-day Lake Michigan, but its shores, especially breached in the area now known as Palos Park, the arcuate south shore, extended inland as far as Chicago, by waters spilling southward over and down­ 10 miles from the present beach. The Chicago area cutting into the moraine. Gradually, the lake level was, from 12,000 to 2,000 years ago, under water as fell. The lowering of the lake level was punctuated was all land now in the state and federal parks. by several still stands, the lake level falling rapidly Lake Chicago (fig. 1) formed about 12,000 years at a given period, only to stabilize for a time, and ago from glacial meltwaters dammed on tl;te south, then fall again. In all, there were three stages of lake­ east, and west by the belt of glacial till called the Val­ level lowering, each level being marked by a beach paraiso Moraine and on the north by the retreating ice and associated series of sand dunes (fig. 2). The oldest mass. The original shoreline stood at 640 feet above and first beach level represents the Glenwood stage Feet Above North South Sea Level 640 ________ -~~QytQ.O.fl_B_e~~h_ a_nl'J~v~I- ______ _ 620 _____ S:~!!J~~1!::!~aEi].~Qd_l~'!.el ____ _ __ Ql~~t.9n !3§~c.ti le~~_ 605 J _ariQ.