A ridge and a mound from one glacial family. Seen from above, they differ in outline, and light can invert that outline. The cross-section shows what light does not change.
What really sets a long ridge apart from a compact mound?
The drawings are our own diagrams, not a map and not a measurement. ‘u.’ is a diagram unit, not a metre; the page measures nothing in the field.
Plan view: the ridge (esker model) and the mound (kame model) at one plan scale. Lines A–A′, B–B′, C–C′ and K–K′ are the section lines; the solid line marks the section shown alongside (A–A′ by default). The small circle with an arrow in the corner shows where the light comes from. own diagram · no measurements
Light on the plan view
Light from the north-west (315°) is the usual direction for shading maps: the slope facing the light is bright, and the ridge reads as a ridge.
Without scripts only the NW setting is shown. With light from the SE (135°) the other slope would be bright, and it is easy to see a trench instead of a ridge (relief inversion). The drawing of the ridge does not change; only the shading does.
Light: NW (315°). Unchanged: section A–A′ has a height of 3.5 u. and a slope (model) of 26.6°; in the model it is a ridge (esker diagram).
The section, detached from the plan view
Without scripts all four sections are shown one below the other. The solid line on the plan view then applies to A–A′ only; the other section lines are dashed and identified by their letters.
A–A′ · across the ridge
A–A′ · across the ridge. A cut at the widest point of the middle hump: width 14 u., height 3.5 u., average slope in the model 26.6° (atan 3.5 / 7). The dashed grey outline is the mound from line K–K′ at the same scale. Hatching means that the internal structure is not known in the diagram. diagram · scale 1 : 1B–B′ · along the ridge. The same ridge seen from the side is a series of three humps with narrowings, not one even embankment. The ridge is 120 u. long; the drawing covers 130 u. The vertical scale is enlarged ×3, and the thin grey outline shows the same profile without enlargement. The maximum local slope along the axis, between a crest and a narrowing, reaches 6.3° (a height difference of 2.2 u. over 20 u.). Hatching: internal structure unknown. diagram · vertical exaggeration ×3C–C′ · oblique, 40° to the axis. A cut through the same point as A–A′, but at an angle. The apparent width grows to 14 / sin 40° = 21.8 u., and the apparent slope falls to 17.8°. The dashed grey outline is A–A′ at the same scale: the height is the same, so the same form looks different only because of the direction of the cut. Hatching: internal structure unknown. diagram · scale 1 : 1K–K′ · through the centre of the mound. A cut in the same direction and at the same scale as A–A′. Width 30 u., height 6 u., average slope 21.8°. The dashed grey outline is A–A′: the mound is more than twice as wide as the ridge and 1.7 times as high. diagram · scale 1 : 1
All four sections side by side (model data, not measurements)
Section
Extent of drawing
Height
Slope (model)
A–A′ across the ridge
40 u.
3.5 u.
26.6°
B–B′ along the ridge, vertical ×3
130 u.
1.3–3.5 u.
up to 6.3° (max. between a crest and a narrowing)
C–C′ oblique, 40° to the axis
40 u.
3.5 u.
17.8° (apparent)
K–K′ through the mound
40 u.
6 u.
21.8°
The slope in A–A′, C–C′ and K–K′ is the average slope of the flank = atan(2 · height / width). In B–B′ there is no single flank: ΔH / ΔL is calculated, that is, the maximum local slope between a crest and a narrowing (2.2 u. over 20 u.). Elongation of the plan (length / width): ridge 120 / 14 = 8.6 : 1, mound 30 / 30 = 1 : 1. This describes the model; it is not an identification test: proportions do not name a form.
Why a hump remains after the ice
Eskers and kames are glaciofluvial landforms: water carried rock material and then deposited it. In the simplified model an esker forms in a tunnel under the ice, and a kame in a basin within a disintegrating ice sheet. When the ice disappears, the lateral support disappears, and the sediment remains as a rise. [3]description from V2/V1, pending approval
In the simplified description from V1, sands and gravels are typical of eskers, while kames also feature finer sands and silts. [3] A ridge may survive as a series of separate mounds; it need not resemble one even embankment. [1]description from V2/V1, pending approval
Esker · in the iceWater flows through a tunnel under the ice and deposits sand and gravel. The ice supports the sediment from the sides.Esker · after the iceThe walls of ice disappear. A ridge remains, which may break up into a series of mounds.Kame · in the iceSediment accumulates in a space bounded by ice, in a basin inside a disintegrating ice sheet.Kame · after the iceAfter the ice has gone, an elevation remains, like Góra Tabaczyna, identified as a kame in the PIG study. [1]
Four illustrative drawings: no scale, no ice thickness and no layer structure. This is a simplification from V1, not a reconstruction of a specific place. Dots mark schematic sediment, without grain size or layers; diagonal hatching is ice. own diagram
Where inference ends
Shape is the beginning. Sediment is the evidence.
Outline: gives a hint but does not settle the origin.
Sediment: is a premise, but one of several.
Interior: internal structure, the arrangement of layers and the geological context decide; they are assessed by a geomorphologist, not by this page.
Light on the plan view changes none of these answers: it is only shading. [4]
The two-question tool (outline and sediment) requires scripts. The rules by which it works are written out in this band: an outline alone or sediment alone is a hint or a premise, and mixed features also remain undecided (a ridge with fine sediment, a single rise with sand and gravel).
no data
No data, not a zero result
We know neither the outline nor the sediment. A lack of knowledge is not the answer ‘neither esker nor kame’, and there is no percentage of certainty. No origin can be assigned.
Limit of inference: agreement with the simplified description from V1 is not an identification. The origin is decided by internal structure, grain size, the arrangement of layers and the geological context; the material and its interpretation must be approved by a geomorphologist.
From diagram to place
The descriptions of places below, together with the paragraph under the list, were taken from V2/V1 and from links that were not reopened. All are ‘to be checked’ and require approval by a geomorphologist. description from V2/V1, pending approval
Turtul esker
A specific example of an esker named in the PIG geological and tourist map. The park also points to it in the description of the trail ‘Doliną Czarnej Hańczy’ [Through the Czarna Hańcza valley]. [1][2]
Góra Tabaczyna
Identified explicitly as a kame in the PIG study. It is a reference point for the second model: sediment accumulated in a space bounded by ice, and an elevation remained after the ice had gone. [1]
Czarna Hańcza valley
In a single valley the park describes an esker, a subglacial channel and a hanging valley. This proximity shows that not every glacial landform is a mound of sediment. [2]
Suwałki Landscape Park brings together, in a small area, moraines, eskers, kames and kettle hollows; this diversity is a record of many processes, not of a single ‘sculpting’ by ice. [4]
The drawings above do not depict the shape of any of these forms. We give no coordinates or directions for getting there, and private plots are not a route.