22: Two Tectonic Plates

The similarity in the structure of the two parts of Lightfall has already been laid out in 18: Two Images. There is a further similarity in that the overall tonality of both parts is shaped by a falling minor third.

[Don't forget that the full score can be downloaded and printed from here.]

(Gustave Dore)

Part One begins clearly in Bb, first with the timpani rhythm, then with the sustained bass note. The next chord to be heard at the peak of the solo (b26) is a G chord. The solo ends on a first inversion of the G chord which puts Bb back in the bass (b30-31). Is the tonality Bb or G? The ambiguity is now firmly established and is maintained throughout the movement by the recurring timpani Bb against the G open fifth in the low strings.

After being slightly off kilter for their first two phrases, the bassoons spell out a rising motive from G minor to Bb minor (b40-41). The woodwinds restate this at various octaves over and over (until b137), further emphasising the tonal uncertainty.

At b137 the various cycles momentarily align on an open G chord which puts the solo horn into a spin playing D an Db repeatedly (b137-140). These two notes are the major and minor third of Bb.

The coda is a reworking of the opening, once again over a pedal Bb now relentlessly pounded out by the timpani. At the same moment as before the G chord is introduced by the low brass (b156) and the movement closes on a G chord in root position. But it is only slightly firmer than when it closed the opening section in first inversion; the Bb is still obstinately in the chord, rasping against the orchestra’s attempt at a major triad on G.

While Part One moved uncertainly from Bb to G, Part Two begins on C, the first five horn notes spelling a C major seventh chord, and ends with the final two bars on an A major chord, which is also a falling minor third.

Part Two is free in spirit and in its early sections flirts with neighbouring tonalities but eventually settles comfortably into a tonality of two sharps (b35). There are no more accidentals in the work except for the recurring C naturals. The reason for this I will discuss in 26: The Landscape – Part Two but for now will point out that C# is the third of A major and that often the A chord is substituted by a C chord in the cycle of harmonies that make up this movement.

Part Two jumps playfully around any tonal ambiguities, only landing on a clear A major chord at the last possible moment as though to say that this is where we were all the time.

Like two great tectonic plates the falling minor third shapes both parts and all the music that is built upon them.

Tectonic Plates

An extra observation:
The first horn note in Part One is a minor third above the bass (b5), as it is when it begins in the main section (b38). In the main section of Part Two (b11-12) the first two notes of the horn are a falling minor third.