Changes

Provenance of sedimentary rocks in subduction zone originates from magmatic-arc. Sediment sources in magmatic-arc provenances come primarily from volcanic rocks. Geochemistry of igneous rock generated in subduction zone depends of the types of crust involved. Island-arc and active continental margin settings provide different proportions of types of minerals. Island-arc tends to produce basalt and andesite, while active continental margin generate volcanic rocks based on degree of assimilation and fractional crystallization of primitive magma.

Provenance of sedimentary rocks in subduction zone originates from magmatic-arc. Sediment sources in magmatic-arc provenances come primarily from volcanic rocks. Geochemistry of igneous rock generated in subduction zone depends of the types of crust involved. Island-arc and active continental margin settings provide different proportions of types of minerals. Island-arc tends to produce basalt and andesite, while active continental margin generate volcanic rocks based on degree of assimilation and fractional crystallization of primitive magma.

Dickinson et. al. (1983) in Boggs<ref name=Boggs /> builds two classifications of provenances based on mineral composition in sandstone. Total quatzose grain, feldspar, and total unstable lithic fragments form one classification, and monocrystalline quartz, feldspar, and unstable clasts plus polycrystalline quartz. The detail of this classification can be reached in Fig. 10.

Dickinson et. al.<ref>Dickinson, W. R., L. S. Beard, G. R. Brakenridge, J. L. Er­ javec, R. C. Ferguson, K. F. Inman, R. A. Knepp, F. A. Lindberg, and P. T. Ryberg, 1983, Provenance of North American Phanerozic sandstones in relation to tecton­ ic setting: Geol. Soc. America Bull, v. 94, p. 222-235.</ref> builds two classifications of provenances based on mineral composition in sandstone. Total quatzose grain, feldspar, and total unstable lithic fragments form one classification, and monocrystalline quartz, feldspar, and unstable clasts plus polycrystalline quartz. The detail of this classification can be reached in Fig. 10.

Magmatic-arc provenances encompass undissected arc, transitional arc, and dissected arc. Undissected arc provides sediments from volcanogenic highlands, where the volcano has not been eroded intensively. Major composition of sandstone from this source is unstable lithic fragments. As volcanism ceases and plutonic rock exposed, undissected arc turns out to be dissected arc. Dissected arc has higher proportion of quarzose grains and feldspar than undissected arc. Transitional arc lies between the two.

Magmatic-arc provenances encompass undissected arc, transitional arc, and dissected arc. Undissected arc provides sediments from volcanogenic highlands, where the volcano has not been eroded intensively. Major composition of sandstone from this source is unstable lithic fragments. As volcanism ceases and plutonic rock exposed, undissected arc turns out to be dissected arc. Dissected arc has higher proportion of quarzose grains and feldspar than undissected arc. Transitional arc lies between the two.