Provenance Analysis Provenance the lithological and chemical isotopic

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Provenance Analysis

Provenance Analysis

Provenance: the lithological (and chemical, isotopic, age) characteristics of the source region for a

Provenance: the lithological (and chemical, isotopic, age) characteristics of the source region for a sedimentary rock Composition of sediments (mostly sandstones) can tell you about the location, tectonic setting, climate, etc. of the source area and the transport mechanism and pathway

Mechanical weathering No changes to mineralogical composition of sediment produced from rock Chemical weathering

Mechanical weathering No changes to mineralogical composition of sediment produced from rock Chemical weathering Mineralogical composition of sediment differs from parent rock

Chemical weathering dominates in warm, wet climates

Chemical weathering dominates in warm, wet climates

Mineral stability during weathering follows Bowen’s reaction series

Mineral stability during weathering follows Bowen’s reaction series

Compositional Maturity: degree to which sediment contains only resistant grains (quartz and stable heavy

Compositional Maturity: degree to which sediment contains only resistant grains (quartz and stable heavy minerals like magnetite, apatite, rutile, zircon)

Textural Maturity: based on presence of clay, sorting, and rounding More transport leads to

Textural Maturity: based on presence of clay, sorting, and rounding More transport leads to greater textural maturity

Rock particles can indicate the tectonic setting of the source QFL diagram plots relative

Rock particles can indicate the tectonic setting of the source QFL diagram plots relative percentages of quartz, feldspar, and lithics If chert or quartzite are abundant, treat them as lithics and plot monocrystalline quartz (Qm)

Other ternary plots (Qp. Lvm. Lsm and Lm. Lv. Ls) subdivide and plot just

Other ternary plots (Qp. Lvm. Lsm and Lm. Lv. Ls) subdivide and plot just the lithic components for discrimination of tectonic settings Qp = polycrystalline quartz (chert, quartzite) Lm = metamorphic lithics Lvm = volcanic and metavolcanic lithics Lv = volcanic lithics Lsm = sedimentary and metased lithics Ls = sedimentary lithics

Sm/Nd isotopes Negative εNd values found in continental crust (Nd system has been separated

Sm/Nd isotopes Negative εNd values found in continental crust (Nd system has been separated from Sm “enriched” mantle for long time) Positive εNd values are commonly found in mantle derived melts

Strontium isotopes (87 Sr/86 Sr) Rubidium (87 Rb) strongly partitions into continental magmas and

Strontium isotopes (87 Sr/86 Sr) Rubidium (87 Rb) strongly partitions into continental magmas and decays to 87 Sr Continental crust is enriched in 87 Sr/86 Sr Primitive mantle and magma have low 87 Sr/86 Sr Ratio tracks continental influence on source rocks

Detrital zircon U-Pb Single-crystal age dates give age of rocks in source region

Detrital zircon U-Pb Single-crystal age dates give age of rocks in source region