Page 118 - Petrology of Sedimentary Rocks

[Greek spelling is Kraton (= established, stable); introduced in geology to Kober in 1921
as “kratogene,” later popularized by Stille as “Kraton.“] Thanks to A.M.C. SegZr for
etymology.

ek

KKAI UN

ORTHOGEOSYNCLINES
and WELTS

The highly mobile Orthogeosynclinal Belt (H. Stille) contains:

W: tectonically active welt, often volcanic; islands or large lands.

e: Eugeosynclinal’ belt (Stille), typically deeply subsiding, very thick sediment
infill (often by turbidites and so-called “flysch”), rich in volcanics and deep-
sea sediments. The outer belt is usually beyond the ken of geologists.
Recent work has shown that it is often a trench overlying a subduction zone
between two tectonic plates (K SO). Between the trench and island arc is
the “arc-trench gap.”

r: a medial ridge or island chain that may or may not be present as a
separation between eu- and miogeosynclinal belts; if it is absent, the two
types of orthogeosynclines may be smoothly transitional. The whole
depression then is often considered a “marginal basin” and may be produced
by “bat k-ar c spreading.”

m: Miogeosynclinal belt (Stille), typically less subsidence, thinner, with local
basins and highs, typically shallow-marine, paralic to continental; essentially
non-volcanic. A strongly uplifted point source may give the exogeosyncline
of Kay (e.g., Catskill “delta,” New York - Penna.).

Either the mio- or the eugeosynclinal belts may be missing, but if both are present the
eugeosyncline is on the oceanward side.

The relatively stable Kraton Region contains:

P: Perikratonic shelves and basins, occurring on the perimeter of the kraton
and fed b the kraton; generally thin blankets or basins that are not
elongated parallel with kraton margins; shallow-water marine sedimex
dominant (stable shelves of Krumbein & Sloss).

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