Paper No. 4
Presentation Time: 9:45 AM
PRELIMINARY RESULTS OF GEOLOGIC MAPPING OF DURWOOD AND FAIRVIEW ROOF PENDANTS, SIERRA NEVADA BATHOLITH (FAIRVIEW QUADRANGLE), TULARE COUNTY, CALIFORNIA
EDMAP-supported geologic mapping of the Fairview 7.5' quadrangle in southern Tulare County, southern Sierra Nevada mountains, southern California, is shedding light on the structure and stratigraphy of two metasedimentary and metavolcanic inliers or roof pendants within the batholith. The "Durwood inlier" is mapped in detail for the first time and appears to represent a Mesozoic(?) metavolcanic and metasedimentary succession similar to those in the Erskine Canyon and Mineral King roof pendants to the south and north, respectively. Its stratigraphy is described for the first time: it is composed of a vertically-dipping, moderately deformed and weakly metamorphosed (lower greenschist?) sequence of (from bottom up) metapelite, metavolcanic rocks, marble, and quartzite. The metavolcanic sequence is composed of water-reworked felsic tuffs including at least one primary pyroclastic density current deposit (ignimbrite) with andesitic clasts, peperite, and andesitic sheet-like intrusions. The “Fairview inlier” is a Paleozoic metasedimentary sequence composed of marine rocks; chiefly turbidites and marbles. Both inliers are characterized by very low to low regional metamorphic grade, strong vertical, north-striking foliation, vertical lineations and localized contact metamorphism from the engulfing batholith. The Fairview inlier appears to be partly structurally controlled by the adjacent proto-Kern Canyon Fault because an asymmetric strain gradient increases in intensity towards the fault trace where it abuts batholitic rocks. The Durwood inlier hosts a major vertical fault within the middle marble unit and may be bounded by a second major shear zone to its immediate east. Studies of these inliers will develop understanding of the assembly of the Sierra Nevada and the role of arc-parallel shear zones in controlling down-warping of supracrustal successions.