V3 · Sonnet

Kaczawa Foothills · site 1 of 3 · the whole silhouette

Land of Extinct Volcanoes

Ostrzyca has a conical silhouette, but today’s hill is a volcanic neck: rock that solidified in the conduit of a former volcano. The cone is gone.

In the drawing alongside, the dashed line is interpretation. It always sits next to a preserved fragment, never in place of it.

Diagram: the preserved neck of Ostrzyca and the open outline of the lost cone A dark, steeply rising mass in the middle represents the preserved volcanic neck. On both sides, two dashed lines run upwards and fade out, because the height of the former cone is not known. The pale blocks on the slopes are a blockfield. In the circle on the right, a honeycomb symbol stands for columnar jointing, with no orientation of the columns. The drawing is a diagram without a scale, not a map or a photograph.
Our own diagram, without a scale: the mass in the middle is the preserved neck; the dashed lines are interpretation and deliberately do not meet at an apex, because the height of the former cone is not known here. The circle in the upper right corner is a symbol of columnar jointing, not a photograph. We do not embed a photograph of Ostrzyca; the link is in the sources.

Ostrzyca: description, inference, limit

Basalt in the summit areas

Description V1, Geopark
Weathering and erosion removed the less resistant rocks surrounding the neck. Basalt remains in the summit areas of the hill.
Inference
Today’s mountain is the resistant interior of a former conduit. The surroundings were less resistant, so they disappeared and the neck remained.
Unknown
The description gives neither the height, the thickness nor the extent of the basalt. The drawing has no scale and the proportions are illustrative.

Regular columns (columnar jointing)

Description V1, Geopark
The regular columns formed as the cooling rock contracted and cracked.
Inference
Columnar jointing is a record of the rock cooling. How to read the direction of heat loss from its pattern is shown in the chapter on Czartowska Skała.
Unknown
This material does not describe the direction of the columns on Ostrzyca, so the drawing shows only a symbol of jointing (a magnified honeycomb), with no orientation. It is a symbol, not a photograph.

Blockfield on the slopes

Description V1, Geopark
The breakdown of basalt forms blockfields on the slopes of Ostrzyca.
Inference
The rubble is secondary to the rock: it is a product of the breakdown of basalt, not a separate element of the former edifice.
Unknown
Extent, thickness and age of the rubble: no data in the material. The placement of the blocks in the drawing is an illustration.

The lost cone

Description V1, Geopark
The eruptive cone no longer exists. The recognisable silhouette is formed by the interior of the volcano.
Inference
The conical shape of today’s mountain comes from the interior of the volcano, not from the original edifice. For that reason the shape of the hill alone is not enough to reconstruct the former volcano.
Unknown
Height, volume and shape of the former edifice: no data in this material. The dashed lines run upwards, do not meet at an apex and fade out, because no apex can be determined from this material. This is not zero, nor a “small cone”.

Site 2 of 3 · jointing in detail

Czartowska Skała

A former quarry exposed a volcanic neck with columns arranged in a fan: almost vertical in the middle, slanting at the sides. Their arrangement makes it possible to read how the rock cooled. The rock is basalt, in the vicinity of Pomocne. The Geopark notes that the exact age of this volcano remains undetermined.

A geometric principle carried over from V2: thermal cracks develop perpendicular to the surface through which the rock loses heat. A curved surface therefore produces columns whose direction changes.

Diagram of columnar jointing: columns perpendicular to a curved cooling surface A mass of rock beneath a curved, dashed line of the cooling surface. From this line into the rock run yellow strokes, that is, columns, always perpendicular to the line. The more curved the surface, the more the outermost columns deviate from the vertical, which is shown by the dotted vertical strokes. The angle values are given in the text beside the drawing. A geometric model, not a measurement.
A geometric model of our own, without a scale. The dashed line is the cooling surface (assumed, not measured), the yellow strokes are columns perpendicular to it, and the dotted strokes mark the vertical. This is not a thermal simulation: it does not calculate temperature, conductivity or time.

Outermost column: tilted 40° from the vertical.

Column on the axis: 0° from the vertical.

Fan: vertical axis, slanting sides. The shape is close to the description of Czartowska Skała (illustrative, not fitted to measurements).

Without JavaScript the slider is unavailable. The drawing shows the setting 35.

For the settings 0, 35 and 100, the outermost column deviates from the vertical by 0°, 40° and 67°. These are model values: the tangent of the angle is proportional to the curvature. The description of Organy Wielisławskie speaks of a change all the way to the horizontal, so the drawing shows the direction of the change, not its full range.

To be checked Access information (as of 27 November 2024, carried over from V2): the Geopark description stated a ban on entering private land. This page is not permission to enter, nor a description of how to get there. Before you set out, check the current rules at the source: Geopark: Czartowska Skała (in Polish).

Site 3 of 3 · relation to the landscape

Organy Wielisławskie

These ‘organs’ are formed by rhyolite, rich in silica, from the Permian period. The rock is exposed at the foot of Wielisławka above the Kaczawa. The columns change their tilt from vertical to horizontal, which, according to the Geopark description, points to a dome of solidifying lava. A similar rhythm of cracks therefore does not mean the same rock or the same age as on basaltic Ostrzyca.

Diagram: a rhyolite cliff above a river and the open outline of a dome The pale background is a schematic silhouette of a hill. At its edge, above the horizontal line of the river, stands a cliff of darker, reddish-grey rock. In the cliff the columns are vertical in the middle and increasingly tilted towards the sides. Above the cliff, two dashed lines outline a dome and fade out, because its height is not known. The drawing is a diagram of relationships, not a plan or a map.
A diagram of relationships, our own, without a scale, not a plan or a map. The background is a conventional silhouette of a hill, the line at the bottom is the river, and the reddish-grey colour distinguishes rhyolite from the dark basalt and does not reproduce the real colour. The angles of the columns come from the geometric model in the chapter on Czartowska Skała, not from field measurements. The dashed outline of the dome is open, because we do not know its height.

Permian rhyolite

Description V1, Geopark
These ‘organs’ are formed by rhyolite, rich in silica, from the Permian period.
Inference
This is a different rock from the basalt of Ostrzyca and Czartowska Skała. A similar rhythm of cracks does not mean the same rock or the same age.
Unknown
We do not give an age in years: there is no figure in the material. The colour in the drawing distinguishes the rock from basalt; it does not reproduce its colour.

Change in the tilt of the columns

Description V1, Geopark
The columns change their tilt from vertical to horizontal.
Inference
According to the Geopark description, this points to a dome of solidifying lava. The change in tilt is a trace of a change in the direction in which the rock lost heat (compare the slider in the chapter on Czartowska Skała).
Unknown
This is the Geopark’s interpretation, not a measurement. The angles in the drawing are calculated from the model, not measured in the field, and do not reach the horizontal.

Cliff above the Kaczawa

Description V1, Geopark
The rock is exposed at the foot of Wielisławka above the Kaczawa.
Inference
This is the only information about location in this material: the cliff lies in a river valley, below a hill. Location alone does not settle the origin of the rock.
Unknown
Height of the cliff, distance from the river and the route of approach: no data. The drawing is not a plan or a map and does not show a route.

Outer part of the dome

Description V1, Geopark
The columns change their tilt from vertical to horizontal; according to the Geopark description, this points to a dome of solidifying lava.
Inference
The arrangement of the columns implies a dome of solidifying lava. Its outer parts, which cannot be seen today, are therefore purely a matter of the model.
Unknown
Extent and height of the dome: no data. The description also does not say how large the dome was or how much of it has been lost. The dashed outline is open and fades out, because there is no value to draw.

Check against over-interpretation · models

The same silhouette, two different interiors

A similar hill shape is not enough to conclude that it is a former volcano. Below are two diagrams with an identical outline. The second is a fictional control example, with no location, kept apart from the three real sites.

Silhouette 1: outline of a cone-shaped hill A smooth outline of a cone-shaped hill. When the interior is revealed, it shows a dark neck with a honeycomb-shaped symbol of cracks, surrounded by pale rock. A model diagram.
Silhouette 1 (model): a neck of hard volcanic rock with columnar jointing, surrounded by rocks that weathering would remove more easily.
Silhouette 2: the same hill outline An outline identical to silhouette 1. When the interior is revealed, it shows horizontal bands of sedimentary rock layers, with no neck and no columnar cracks. A fictional control example.
Silhouette 2 (fictional example D): horizontal layers of sedimentary rock, with no neck and no jointing. A hill carved by erosion alone.

Interiors revealed: the same silhouette, two different interiors. Only the rock and the features within it tell them apart, not the outline.

Explanation and limits

What we know, and what this page does not settle

For each site: what the material describes and what data are missing
OstrzycaBasalt at the summit, regular columns, blockfield, a neck instead of a cone.No data: height of the former cone, orientation of the columns, extent of the blockfield.
Czartowska SkałaBasalt, a neck exposed in a quarry, columns in a fan.No data: exact age (Geopark: undetermined), current access.
Organy WielisławskiePermian rhyolite, columns from vertical to horizontal, a lava dome (the Geopark’s inference).No data: age in years, height of the cliff and of the dome, route of approach.

A hatched cell means there are no data in the material. This is not zero, nor a “small value”.

How to read the diagrams

  • Description is content carried over from V1 and V2 (Geopark descriptions, Prof. Piotr Migoń). It was not re-checked in this version.
  • Inference is a geological interpretation drawn from those descriptions, not an independent measurement.
  • Unknown is a gap in the material, drawn as a fading line or a hatched area.
  • All the drawings are our own diagrams without a scale. They are not maps or photographs and do not identify rocks in the field.

What was removed from V2

  • A quiz with feature ticking and a list of hypotheses, with a “consistent/inconsistent” verdict: replaced by picking a feature, which immediately shows the description, inference and limit. No scoring.
  • A notebook in browser storage and a TXT export: dropped. The page saves nothing. Entries from V2 may remain in the browser under the key atlas-v2-76, and the reader removes them in the browser settings.
  • Layer switches and “Two boards”: replaced by a fixed pairing of fragment and interpretation in a single drawing.
  • A photograph of Ostrzyca from Wikimedia Commons: not embedded, so that the page works offline. The link is in the sources.
  • The fourth tab, “Control example”: moved to a separate section and labelled as fictional.

What was kept

  • The descriptive texts for the sites, the dated access information and the source links.
  • The principle that columnar jointing aligns perpendicular to the surface through which heat is lost, as a chapter with a slider.

Sources

Links carried over from V2

The addresses were carried over from V2. In this version they were neither opened nor re-checked and need verifying. The links open in a new tab and are not needed to display the page.