ABSTRACT
Mount Merino Chert and Shale, Middle Ordovician, is one of the
most siliceous units of the Taconic sequence (eastern New York and
western Vermont); it is composed of interbedded shale, siliceous
hale, argillite and chert. Non-clastic quartz — aggregates of
quartz having a.mosaic or felted texture — predominates in all
beds, except `shale. All siliceous beds are finely laminated; most
laminae are distinguished from adjacent laminae by the texture of
the quartz groundmass, and the amount of clastics, carbonates,
chlorite and sulphides. Statistical comparison of the textures of
the quartz aggregates which occur with the other mineral
components suggests that the components of each lamina represent a
stable mineralogic assemblage; the assemblages probably formed
during silica precipitation and early diagenesis. These
assemblages are compositionally-consistent with experimental data
regarding the formation of authigenic minerals in the presence of
colloidal silica.
Mount Merino rocks comprise a minor.part of the Giddings Brook
slice of the Taconic allochthon; the Mount Merino fauna is the
youngest of the Giddings Brook slice rock sequence. Mount Merino
rocks also occur as boulders and blocks in Forbes Hill
Conglomerate, an autochthonous wildflysch-like terrain underlying
the Giddings Brook slice.
Petrographic aspects of Mount Merino rocks indicate a "starved"
depositional environment distant from an extensive land area. The
predominant source of silica for the rocks was probably vulcanism
(the Ammonoosuc volcanics) which became relatively intense during
Mount Merino time, just preceding emplacement of the Taconic
allochthon.
Lang, D.M., 1969. Origin of the Mount Merino Chert and Shale,
Middle Ordovician, Eastern New York State.
Unpublished MSc. thesis, State University of New York at
Albany. 64pp., +v, +26p. tables.
University at Albany Science Library call number: SCIENCE
Oversize (*) QE 471 L325X
thesis scanned text with
greyscale pictures) - 12.9MB pdf file
Map 1 - sample location map
- 0.4MB pdf file
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