Geology of the Noel Paul's Brook area, central Newfoundland

Mullins, John (1961) Geology of the Noel Paul's Brook area, central Newfoundland. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (28MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

This thesis is concerned with a study of the general geologic features of the Noel Paul’s Brook area in Central Newfoundland, with emphasis on the systematic description and classification of rock types. -- In the gently rolling terrain the remnants of two Cenozoic erosion surfaces may still be recognized. As a result of Pleistocene glaciation the countryside has been left with a think mantle of boulder clay, but because of two conflicting lines of evidence no definite conclusion as to the direction of glacial ice motion could be reached. -- The bedrock geology is characterized by narrow - often persistent - bands of clastic sedimentary rocks and volcanic formations striking approximately northeast. Their total thickness, if the possibility of repetition through isoclinal folding is disregarded, is over 30,000 feet. With the exception of one conglomerate member the sedimentary rocks are fine grained. The volcanic rocks consist of metamorphosed acid and intermediate flows and tuffs. The intermediate rocks are associated with thin bands of slightly metamorphosed limestone, limy shale and greenstones of sedimentary origin. -- A large granite batholith lies along the southern boundary of the map area, and smaller intrusive stocks, sills and dikes, ranging in composition from diorite to micropegmatite also occur. -- No fossils were found in the sedimentary rocks, but by lithological correlation with rocks beyond the thesis area the formations mapped are believed to range in age from middle Ordovician to post-Ordovician. -- It is believed that the rocks were deformed by two major orogenies: one in the late Ordovician, the other late in the Devonian period. The conglomerate member mentioned above may have formed in connection with the late Devonian upheaval. -- The sedimentary rocks have steep dips, generally in a southeasterly direction, but the beds are often overturned. These high dips are indicative of tight, isoclinal folding, and observation of minor folds tends to support this assumption. Faults are not conspicuous, but shearing and brecciation of outcrops in some areas suggest that faulting has taken place in the vicinity of these outcrops. -- The great thickness of the stratigraphic sequence and the abundance of volcanic rocks, some of which show pillow structure, indicate a eugeosynclinal environment. However, most of the sedimentary rocks have characteristics which suggest deposition in a deltaic or terrestrial environment.

Actions (login required)

View Item