The slate terrain is the main constituent of the Taiwan mountain belt and crops out extensively on its western flank and crest. The rocks of the slate terrain are metamorphosed Tertiary sediments deposited on the Chinese continental margin, devoid of effects from orogenic events in the Mesozoic, therefore they are best suited to studying the evolution of the current late-Cenozoic Penglai orogeny of Taiwan. Numerous hypotheses on the growth and development of the Taiwanese orogenic wedge have been proposed leading to contrasting mountain building models, notably the thin-skinned classic wedge model with a constant detachments fault, the complex wedge model with significant basal accretion, and the lithospheric collision model; each of the models has its own prediction on particle paths through the wedge, hence different rock P-T (pressure-time) histories. Quantitative documentation of slate belt rock history thus serves to be the key in discriminating the validity of the above models to the Taiwan mountain belt. This study employs the novel RSCM (raman spectroscopy of carbonaceous material) geothermometer to quantify the peak temperature/metamorphic state through measuring the graphitization degree of the organic detritus within the metasediments, then reconstruct the rock history by integrating field geologic and structural data alongside stratigraphic information and thermochronological data. The competing mountain building models will be verified against the resultant rock cycle documentations. In-situ 40Ar/ 39Ar microprobe dating will be carried out on rocks with well-constrained thermal history as above and with large K-bearing syn-kinematic mineral growths, to place crucial information on timing and time scales in the established rock P-T histories. 4 years of works has been preliminarily anticipated, with the first year on establishing the laboratory and on thermal metamorphic investigation in the northern part of the slate terrain; during the second year the slate terrain in central Taiwan will be investigated; for the third year focus will be placed on the boundary between the Hsuehshan and Backbone ranges to inspect the nature of the inter-range contact; in the fourth year the intervening regions between the surveyed route of the previous three years will be investigated, and sums up the results of the whole four years.
|Effective start/end date||1/08/18 → 31/12/19|
In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):