PROVENANCE DETERMINATION USING DETRITAL IRON-TITANIUM OXIDES AND CLINOPYROXENES

Chemistry, texture and composition of iron-titanium oxides have been used in provenance determination. The detrital sediments located on the south central coast of Jamaica were examined using petrographic and chemical techniques. The mineralogy consists of iron-titanium oxides namely; ilmenite, ulvospinel, titanomagnetite and magnetite, clinopyroxene (augites and diopsides), hornblende (magnesiohornblende, tschermakite and magnesiohastingsite), and lesser amounts of epidote. The main textures found in the iron-titanium oxides are (1) sandwich, (2) composite, (3) trellis, (4) lensoid, (5) curvilinear, and (6) homogeneous (single-phase grains). The sandwich texture involves lamellar ilmenite-hematite intergrowths. The composite texture consists of variable compositions and textural types. Each of the other textural types (except the homogeneous texture) consists of an intergrowth of two or more iron-titanium oxides. It has been established that the chemistry of the iron-titanium oxide pairs can be used to establish the temperature and oxygen fugacity, from which can be inferred the temperature of re-equilibration of the host rocks (cooling history). Also, the relative proportions of the oxides (except where alteration has taken place) found in the different phases are consistent with particular host rocks found in the drainage basin. The study demonstrates the usage of iron-titanium oxides, along with clinopyroxenes in the determination of provenance of the detrital sediments.