Zeolite to prehnite-pumpellyite facies metamorphism in the Toa Baja drill hole, Puerto Rico

Journal Article · Fri Mar 01 00:00:00 EST 1991 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/91GL00409· OSTI ID:5597807

Cho, M ^[1]

---

1. Stanford Univ., CA (United States)

Secondary mineral assemblages in Eocene volcanic and volcaniclastic rocks of the Toa Baja drill hole progressively change as a function of depth. Four metamorphic zones are delineated with increasing depth: Ca-clinoptilolite{yields}heulandite{yields}laumontite{yields}prehnite-pumpellyite zone. The deepest belongs to the prehnite-pumpellyite facies, whereas the three zones at shallower depths (< 2,350 m) belong to the zeolite facies. Ca-clinoptilolite and heulandite exhibit continuous solid solution with varying Si/Al (2.9-5.2) and Ca/(Ca + Na + K) ratios (0.45-0.89). Pumpellyites are characterized by extensive variation in the Fe/(Fe + Al + Mg) ratio (0.29-0.74) and extreme Fe-enrichment in the laumontite zone. Temperatures estimated from mineral assemblages and facies transitions suggest that the North Coast Basin, Puerto Rico, has been subject to a metamorphic field gradient of {approximately}50 to 70C/km.

• OSTI ID: 5597807
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Vol. 18:3; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
02 PETROLEUM
PETROLEUM DEPOSITS
METAMORPHISM
MINERALOGY
PUERTO RICO
DEPTH
GEOCHEMISTRY
LITHOLOGY
MINERALS
PHASE TRANSFORMATIONS
RESERVOIR TEMPERATURE
VOLCANIC ROCKS
ZEOLITES
CHEMISTRY
DEVELOPED COUNTRIES
DIMENSIONS
GEOLOGIC DEPOSITS
GREATER ANTILLES
IGNEOUS ROCKS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
ISLANDS
LATIN AMERICA
MATERIALS
MINERAL RESOURCES
NORTH AMERICA
RESOURCES
ROCKS
SILICATE MINERALS
USA
WEST INDIES
580000* - Geosciences
020200 - Petroleum- Reserves
Geology
&amp; Exploration