Home Multi-Country Search About Admin Login
Cenozoic
Mesozoic
Paleozoic
Neoproterozoic
Mesoproterozoic
Paleoproterozoic

Search by
Select Region(s) to search
Hold Ctrl (Windows/Linux) or Command (Mac) to select multiple
Bhimphedi Gr
Click to display on map of the Ancient World at:
Bhimphedi Gr base reconstruction

Bhimphedi Gr

Period: 
Ediacaran, Cambrian, Ordovician

Age Interval: 
Ediacaran-earliest Cambrian then a jump to early-Late Ordovician


Province: 
Nepal Lesser Himalaya

Type Locality and Naming

Katmandu region (Tethyan sequence)


Lithology and Thickness

"The Bhimphedi Group represents an approximately 8 km thick metamorphic succession, composed of schists, quartzites, marbles, and allied rocks together with Sheopuri Injection Gneisses and Paleozoic granites. The original sedimentary rocks were mainly shales and sandstones with two prominent limestone intervals.

The Bhimphedi Group begins with the Raduwa Fm, represented dominantly by dark green-gray mica schists of coarse crystalline aspect. The main component of the Bhainsedobhan Marble Fm at its type locality appears in coarse to very coarse crystalline (up to a few mm long calcite grains), saccharoidal form. Mica schists comprise the main rock type of the Kalitar Fm. The Kalitar Fm is succeeded transitionally by the Chisapani Quartzite Fm [although Martin, 2017, diagram implies a major discontinuity spanning the majority of the upper Cambrian and lower Ordovician]. The Chisapani Quartzite Fm serves as a light-colored marker band, separating the underlying much darker schists and quartzites of the Kalitar Fm from the overlying Kulikhani Fm. The Chisapani Quartzite Fm represents a conspicuous, very fine-grained, white to pale green, clean quartztite with sericite partings or thin sericite–phyllite seams. The overlying Kulikhani Fm consists of fine-grained quartz and mica in various proportions, resulting in the bands of micaceous quartzite and quartzitic schist. The Markhu Fm is composed mainly of three rock types: schists, quartzites, and carbonates, occurring in various proportions."


Lithology Pattern: 
Sandy claystone


Relationships and Distribution

Lower contact

The Mahabharat Thrust or Main Central Thrust brings the Kathmandu Complex (of which this is the lower group) over the Upper Nawakot Gr (Robang Fm is the uppermost preserved unit). However, on some rare occasions, the thrust approaches the Siwaliks, concealing the whole Lesser Himalayan sequence.

Upper contact

"Through a decrease in the number and thickness of carbonate bands, the Markhu Fm [top of this Bhimphedi Gr] transitionally grades into the overlying Tistung Fm [lowest unit of the Phulchauki Gr]."

Regional extent


GeoJSON

{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[80.69,29.05],[80.69,28.99],[82.16,28.29],[83.81,27.82],[85.31,27.01],[86.61,26.7],[87.8,26.7],[87.49,26.98],[85.91,27.2],[84.91,27.97],[84.24,28.17],[83.63,28.35],[82.48,28.63],[81.57,28.92],[80.69,29.05]]]]}}

Fossils


Age 

A large time span which includes a major discontinuity between the interpreted Ediacaran suite and the late Ordovician (Sandbian?) suite.

Age Span: 

    Beginning stage: 
Ediacaran

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
635.00

    Ending stage: 
Sandbian

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
452.75

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

Descriptions from Megh Raj Dhital (2015, Geology of Nepal: Regional Perspective of the Classic Collided Orogen, Springer Publ., 499 pp.). Age spans estimated from correlation diagrams in Martin, A.J. (2017, "A review of Himalayan stratigraphy, magmatism, and structure", Gondwana Research, 49: 42-80; http://dx.doi.org/10.1016/j.gr.2017.04.031), but these are often controversial.