Geologic History of the Little River
Little River Wetlands Project
Glacial abrasion and erosion processes.
Landforms created by retreating glaciers.
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Piracy and Capture in Pleistocene Allen and Huntington Counties
In pre-Illinoisan Glacial times, Allen and Huntington Counties lay in the middle of the Wabash-Erie trough, some 200 miles long, 100 miles wide and 200
feet deep. The trough extended along a NE-SW axis to the Illinois border. Just west of present Fort Wayne, the bottom of the trough sloped gently toward
either end.
The Erie lobe of the Wisconsin Glacier inflicted dramatic changes in the existing topography of Allen and Huntington Counties. In other parts of North
America, even more dramatic changes occurred. Yet, in Allen and Huntington Counties it was so unique as to be a major factor in later historical events.
These events shaped the struggle for control of a large part of this same North American continent. The Wisconsin Glacier began about 70,000 years ago
it had reached it's maximum in Central Indiana. By 15,000 years ago, it had retreated to northern Indiana, and by 12,000 yrs. BP was nearly out of Indiana
In pre-Illinoisan Glacial times, Allen and Huntington Counties lay in the middle of the Wabash-Erie trough, some 200 miles long, 100 miles wide and 200
feet deep. The trough extended along a NE-SW axis to the Illinois border. Just west of present Fort Wayne, the bottom of the trough sloped gently toward
either end.
The Erie lobe of the Wisconsin Glacier inflicted dramatic changes in the existing topography of Allen and Huntington Counties. In other parts of North
America, even more dramatic changes occurred. Yet, in Allen and Huntington Counties it was so unique as to be a major factor in later historical events.
These events shaped the struggle for control of a large part of this same North American continent. The Wisconsin Glacier began about 70,000 years ago
it had reached it's maximum in Central Indiana. By 15,000 years ago, it had retreated to northern Indiana, and by 12,000 yrs. BP was nearly out of Indiana
The Last Glacier Retreats
The Wisconsin Glacier retreated in irregular stages, leaving crescent-shaped ridges or terminal moraines at right angles to itís line of retreat. One of
these, the Fort Wayne Moraine, was the last in Indiana, and the last for 40 or more miles eastward. It was very strategically located near the existing
pre-glacial drainage divide. Dramatic changes in and around this moraine involving the St. Marys, St. Joseph, Eel Little Wabash Rivers and Cedar Creek,
and most importantly, the Maumee River occurred over the next 2000 year or so.
The Wisconsin Glacier retreated in irregular stages, leaving crescent-shaped ridges or terminal moraines at right angles to itís line of retreat. One of
these, the Fort Wayne Moraine, was the last in Indiana, and the last for 40 or more miles eastward. It was very strategically located near the existing
pre-glacial drainage divide. Dramatic changes in and around this moraine involving the St. Marys, St. Joseph, Eel Little Wabash Rivers and Cedar Creek,
and most importantly, the Maumee River occurred over the next 2000 year or so.
Water, Water Everywhere!
Melting ice formed Glacial Lake Maumee, filling the basin and finally spilling over two notches in the Ft. Wayne moraine. Water drained westward, down
the Little River Sluiceway in what is now called the "Maumee Torrent". Accompanying this torrent were waters from frontal glacial margin rivers, St.
Joseph, St. Marys, and the Eel, draining west to the Wabash River. Some geologists estimate that the torrent may have lasted as much as two weeks
before Glacial Lake Maumee was drained sufficiently to cease pouring over the notch in the moraine. The Eel was a frontal margin river to the Wabash
Moraine nearby.
Water Must Seek Its Level Piracy!
Erosion of this spillway continued until two things happened. First, silt was deposited beyond the moraine to the west, and second, as Glacial Lake
Maumee receded, water no longer spilled westward through the Ft. Wayne outlet. Eventually the Maumee Lake, now a river after a few hundred years,
itself reversed direction conforming to the pre-glacial drainage, and captured or ëpiratedí the St. Marys and St. Joe rivers from the Wabash system. They
now became tributaries to the Maumee River, an inlet to present day Lake Erie, as opposed to an outlet to Glacial Lake Maumee!
As a side drama, similar piracy occurred with Cedar Creek and the Upper Eel River. Cedar Creek was a tributary feeder to the Eel River. Eventually it cut
through the Wabash Moraine, depositing silt below itís juncture with the Eel. As glacial recession continued, the upper part of the Eel was cut off from itís
lower part. Drainage was re-established in reverse direction, through the Cedar Creek and notch and into the St. Joe River! Thus, the Lake Erie basin
drainage system captured ìthree an a half riversî once belonging to the Wabash drainage system, and left Little River Sluiceway abandoned, except for
local drainage.
The stage was then set for historic times. Native Americans, English, French and fledgling Yankees battled from 1600 to 1850 over the economic
realities of this portage area between the two great River systems. These economic forces had been spawned by violent natural forces over the
preceding 10,000 years.
Melting ice formed Glacial Lake Maumee, filling the basin and finally spilling over two notches in the Ft. Wayne moraine. Water drained westward, down
the Little River Sluiceway in what is now called the "Maumee Torrent". Accompanying this torrent were waters from frontal glacial margin rivers, St.
Joseph, St. Marys, and the Eel, draining west to the Wabash River. Some geologists estimate that the torrent may have lasted as much as two weeks
before Glacial Lake Maumee was drained sufficiently to cease pouring over the notch in the moraine. The Eel was a frontal margin river to the Wabash
Moraine nearby.
Water Must Seek Its Level Piracy!
Erosion of this spillway continued until two things happened. First, silt was deposited beyond the moraine to the west, and second, as Glacial Lake
Maumee receded, water no longer spilled westward through the Ft. Wayne outlet. Eventually the Maumee Lake, now a river after a few hundred years,
itself reversed direction conforming to the pre-glacial drainage, and captured or ëpiratedí the St. Marys and St. Joe rivers from the Wabash system. They
now became tributaries to the Maumee River, an inlet to present day Lake Erie, as opposed to an outlet to Glacial Lake Maumee!
As a side drama, similar piracy occurred with Cedar Creek and the Upper Eel River. Cedar Creek was a tributary feeder to the Eel River. Eventually it cut
through the Wabash Moraine, depositing silt below itís juncture with the Eel. As glacial recession continued, the upper part of the Eel was cut off from itís
lower part. Drainage was re-established in reverse direction, through the Cedar Creek and notch and into the St. Joe River! Thus, the Lake Erie basin
drainage system captured ìthree an a half riversî once belonging to the Wabash drainage system, and left Little River Sluiceway abandoned, except for
local drainage.
The stage was then set for historic times. Native Americans, English, French and fledgling Yankees battled from 1600 to 1850 over the economic
realities of this portage area between the two great River systems. These economic forces had been spawned by violent natural forces over the
preceding 10,000 years.