Visitors often experience Iceland’s geothermal wonders as isolated attractions—Geysir erupting in the south, hot springs boiling at Deildartunguhver in the west, rifting on display at Þingvellir. But when viewed through the lens of long-roll mantle convection, these sites reveal a striking order. They are not randomly scattered. Instead, they follow the geometry of a single, large-scale convection-roll polygon whose division lines extend from the Reykjanes Ridge deep into Iceland’s interior.
The Golden Circle occupies the southeastern side of this polygon, while the scenic geothermal and volcanic features of West Iceland mark the northwestern side. Together, they form a coherent and predictable system—one that becomes unmistakable once the underlying structure is recognized.
An overview:
For more detailed view:
The Southeastern Side: Golden Circle Precision
Þingvellir
Þingvellir sits near the center of the polygon, directly on its north–south axis. Here, equal pulling forces from both sides create the famous rift valley. Its placement is a textbook example of where the interior of a convection polygon should produce surface extension.
Hveragerði
Hveragerði offers one of Iceland’s cleanest demonstrations of deep-mantle structure expressed at the surface. The town lies exactly at the intersection of major mantle division lines, which explains the intensity and concentration of geothermal activity. It is a surface hotspot perfectly predicted by the geometry below.
Laugarvatn
Laugarvatn also aligns with exceptional accuracy. The geothermal area sits on two upper-level down-welling lines and lies directly above a major lower-mantle division boundary. Few places illustrate the coupling of shallow and deep mantle dynamics as clearly as Laugarvatn.
Geysir
Geysir rests directly on the down-welling line that extends northwest from Hekla. It also lies just southeast of the structural intersection that defines the north corner of the polygon’s southeastern side. This convergence of trends helps explain why the geothermal field is so active and persistent.
Gullfoss
The gorge of Gullfoss aligns with the same down-welling division pattern that links Hekla, Geysir, and the West Iceland features. The waterfall marks the upper end of a gorge whose orientation is controlled by the polygon’s structural lines.
These Golden Circle sites collectively trace the southeastern edge of the polygon with remarkable precision—far too precise to be coincidental.
The Northwestern Side: West Iceland’s Mirror Image
The same polygon continues seamlessly northwest, and the geothermal and volcanic features there align with the same degree of accuracy.
Reykholt
Reykholt lies on a major upwelling line extending from the Reykjanes Ridge. This upwelling brings heat toward the surface, establishing Reykholt as a thermal center on the polygon’s NW side.
Deildartunguhver
Iceland’s most powerful hot spring sits on the calculated continuation of the main part of the Reykjanes Ridge, and exactly on the east–west axis that cuts through the Reykholtsdalur area—a key boundary separating upwelling and down-welling segments. Its location makes complete structural sense when placed on the polygon map.
Hraunfossar & Barnafoss
These hydrological features lie on the other upwelling line from the Reykjanes Ridge and near the east corner of the Reykholtsdalur mini-polygon. The unusual phenomenon of water emerging directly from lava fields reflects this deeper structural positioning.
West Iceland’s features are therefore not separate anomalies—they are the northwestern continuation of the same convection-roll polygon that shapes the Golden Circle.
A Unified Geological Framework
When viewed together, the Golden Circle and West Iceland’s geothermal fields reveal a single, coherent pattern. They form opposite sides of the same polygon, shaped by long-roll mantle convection. Each site—Hveragerði, Laugarvatn, Geysir, Reykholt, Deildartunguhver, Hraunfossar—sits exactly where the division lines predict, demonstrating the extraordinary consistency of this framework.
Iceland’s most famous natural attractions are not isolated surface features.
They are windows into the geometry of the deep Earth.
Magic Magma 