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Baxa Gr

Baxa Gr

Period: 
Cambrian

Age Interval: 
middle to late Cambrian


Province: 
Bhutan

Type Locality and Naming

Lesser Himalaya. Manas Fm of conglomerate followed by Phuentsholing Fm of slate interbedded with limestone. Long et al (2011) had also included the older Pangsari Fm of phyllite, but Martin (2017) put that Pangsari Fm separately due to major hiatus between it (re-interpreted as Mesoproterozoic, ca. 1600 Ma) and the higher formations (and also recommended abandoning the term "Baxa Gr" entirely to avoid confusion on what it included).


Lithology and Thickness

See individual formations


Lithology Pattern: 
Sandy claystone


Relationships and Distribution

Lower contact

Major unconformity (ca. 1 billion years!) onto "Sikkim dolomite" (Martin, 2017, diagram) that overlies Pangsari Fm.

Upper contact

Major unconformity (Ordovician through Carboniferous are absent) below the Diuri Fm (western Bhutan) or Rangit Fm (eastern Bhutan)

Regional extent


GeoJSON

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Fossils


Age 

Middle through late Cambrian?

Age Span: 

    Beginning stage: 
Cambrian Stage 4

    Fraction up in beginning stage: 
0.0

    Beginning date (Ma): 
514.50

    Ending stage: 
Cambrian Stage 10

    Fraction up in the ending stage: 
1.0

    Ending date (Ma):  
486.85

Depositional setting


Depositional pattern:  


Additional Information


Compiler:  

Extract from Legend to "Geologic Map of Bhutan" (Long, S., McQuarrie, N., et al., 2011, Journal of Maps). 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.