TY - JOUR
T1 - Weathering and abrasion of Fe-Ti oxides during rock degradation and fluvial transport
T2 - Implications for sedimentary provenance studies
AU - Martinez-Monasterio, E.
AU - Stephens, W. E.
AU - Walden, J.
AU - Duck, R. W.
PY - 2000/5
Y1 - 2000/5
N2 - Physical and chemical degradation of individual grains of titanomagnetite and ilmenite during rock weathering and fluvial transport processes in the River Eden catchment, Eastern Scotland, have been traced using backscattered electron images and electron probe microanalysis. Magnetic characteristics have been used to detect differences in magnetic mineralogy concentration, paragenesis and grain size between rock samples showing different stages of weathering, and between different sources and sediment samples. Results have shown higher physical and chemical durability of ilmenite during this segment of the geological cycle than titanomagnetite, which is rapidly altered. During progressive subaerial weathering of a dolerite, the increasingly intensive and extensive oxidation and development of internal fractures in titanomagnetite are observed. However, under subaqueous conditions, titanomagnetite was found to be progressively replaced by titanite and Ti-impoverished magnetite due to hydrocirculation. Neither the total physical nor the total compositional degradation of titanomagnetite is achieved under rock weathering and fluvial transport processes. Thus, the importance of titanomagnetite as a provenance indicator remains despite its degradation during the geological processes studied in the River Eden catchment.
AB - Physical and chemical degradation of individual grains of titanomagnetite and ilmenite during rock weathering and fluvial transport processes in the River Eden catchment, Eastern Scotland, have been traced using backscattered electron images and electron probe microanalysis. Magnetic characteristics have been used to detect differences in magnetic mineralogy concentration, paragenesis and grain size between rock samples showing different stages of weathering, and between different sources and sediment samples. Results have shown higher physical and chemical durability of ilmenite during this segment of the geological cycle than titanomagnetite, which is rapidly altered. During progressive subaerial weathering of a dolerite, the increasingly intensive and extensive oxidation and development of internal fractures in titanomagnetite are observed. However, under subaqueous conditions, titanomagnetite was found to be progressively replaced by titanite and Ti-impoverished magnetite due to hydrocirculation. Neither the total physical nor the total compositional degradation of titanomagnetite is achieved under rock weathering and fluvial transport processes. Thus, the importance of titanomagnetite as a provenance indicator remains despite its degradation during the geological processes studied in the River Eden catchment.
KW - Ilmenite
KW - Stream transport
KW - Titanite
KW - Titanomagnetite
KW - Weathering
UR - http://www.scopus.com/inward/record.url?scp=0034121439&partnerID=8YFLogxK
U2 - 10.1144/jgs.157.3.601
DO - 10.1144/jgs.157.3.601
M3 - Article
AN - SCOPUS:0034121439
SN - 0016-7649
VL - 157
SP - 601
EP - 613
JO - Journal of the Geological Society
JF - Journal of the Geological Society
IS - 3
ER -