scholarly journals Diagenesis of Hydrocarbon-bearing Concretions in South-central Puerto-rico: Tectonism and Early hydrocarbon Generation

2021 ◽  
Author(s):  
ting ding ◽  
Luis A. González ◽  
Fu sheng Guo ◽  
Yang Xu
Keyword(s):  
Puerto Rico ◽  
Geothermal Gradient ◽  
Hydrocarbon Generation ◽  
Sulfate Reducing ◽  
Carbonate Cements ◽  
South Central ◽  
Fracture Formation ◽  
The Matrix ◽  
Pyrite Formation ◽  
Reducing Environment

Abstract Carbonate concretions within tuffaceous mudstones in the Upper Cretaceous Cariblanco Formation of south-central Puerto Rico that contain solid and liquid hydrocarbons were affected by: 1) Three distinct events of vein/fracture formation accompanied or followed by sediment infilling; 2) pyrite formation throughout the concretion matrix, in foraminiferal chambers, and sediment vein fills; 3) four events of larger vein and fracture formation infilled by distinct calcite cements that postdate sediment infilled veins; 4) a late quartz void filling cement; and 5) formation of calcite-filled veinlets that crosscut all components. Petrographic and isotopic data suggest early concretion formation and septarian vein fills, close to the sediment-water interface, prior to any significant dewatering of infilling sediments. The δ13C values of the matrix and sediment infills (-15 to -30‰ PDB), their brightly luminescent character, and the sequestering of Fe into pyrite indicate formation in a sulfate-reducing environment with influx of diffusing methane. Fluid inclusion data, isotopic composition of carbonate cements (13C enrichments from − 18 to -8‰ and 18O depletion from − 4 to -12‰), and organic matter maturation suggest maximum burial temperatures of 150 to 200°C. Calcite cements and microspars were formed by the circulation of progressively warmer fluids, with warming induced by the gradual emplacement of the nearby Los Panes intrusion. The intrusion probably caused intense normal faulting, induced extensive warm fluid circulation, and resulted in a high geothermal gradient responsible for early hydrocarbon generation.

HYDROCARBON HABITAT OF THE COOPER/EROMANGA BASIN, AUSTRALIA

1983 ◽  
Vol 23 (1) ◽  
pp. 75 ◽  
Author(s):  
A. J. Kantsler ◽  
T. J. C. Prudence ◽  
A. C. Cook ◽  
M. Zwigulis
Keyword(s):  
Geothermal Gradient ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Oil Generation ◽  
Late Tertiary ◽  
Modelling Studies ◽  
Permian Coal ◽  
Intracratonic Basin ◽  
Hydrocarbon Charge ◽  
Eromanga Basin

The Cooper Basin is a complex intracratonic basin containing a Permian-Triassic succession which is uncomformably overlain by Jurassic-Cretaceous sediments of the Eromanga Basin. Abundant inertinite-rich humic source rocks in the Permian coal measures sequence have sourced some 3TCF recoverable gas and 300 million barrels recoverable natural gas liquids and oil found to date in Permian sandstones. Locally developed vitrinitic and exinite-rich humic source rocks in the Jurassic to Lower Cretaceous section have, together with Permian source rocks, contributed to a further 60 million barrels of recoverable oil found in fluvial Jurassic-Cretaceous sandstones.Maturity trends vary across the basin in response to a complex thermal history, resulting in a present-day geothermal gradient which ranges from 3.0°C/100 m to 6.0°C/100 m. Permian source rocks are generally mature to postmature for oil generation, and oil/condensate-prone and dry gas-prone kitchens exist in separate depositional troughs. Jurassic source rocks generally range from immature to mature but are postmature in the central Nappamerri Trough. The Nappamerri Trough is considered to have been the most prolific Jurassic oil kitchen because of the mature character of the crudes found in Jurassic reservoirs around its flanks.Outside the central Nappamerri Trough, maturation modelling studies show that most hydrocarbon generation followed rapid subsidence during the Cenomanian. Most syndepositional Permian structures are favourably located in time and space to receive this hydrocarbon charge. Late formed structures (Mid-Late Tertiary) are less favourably situated and are rarely filled to spill point.The high CO2 contents of the Permian gas (up to 50 percent) may be related to maturation of the humic Permian source rocks and thermal degradation of Permian crudes. However, the high δ13C of the CO2 (av. −6.9 percent) suggests some mixing with CO2 derived from thermal breakdown of carbonates within both the prospective sequence and economic basement.

scholarly journals First Report of Squash vein yellowing virus Affecting Watermelon and Bitter Gourd in Puerto Rico

Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1516-1516 ◽  
Author(s):  
V. Acevedo ◽  
J. C. V. Rodrigues ◽  
C. E. de Jensen ◽  
C. G. Webster ◽  
S. Adkins ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Fungal Pathogens ◽  
Citrullus Lanatus ◽  
Direct Sequencing ◽  
Bitter Gourd ◽  
Growth Stages ◽  
Mechanical Inoculation ◽  
First Report ◽  
South Central ◽  
Yellowing Virus

In 2005, symptoms of watermelon vine decline (WVD) were observed on a 200-acre watermelon farm in Santa Isabel, on the south central coast of Puerto Rico. WVD symptoms included leaf curling, mosaics, and internode necrosis. In early growth stages of WVD, reduced vigor and plant stunting occurred. At flowering, symptoms progressed to necrosis and wilting of vines. A 2006 to 2007 survey demonstrated that fungal pathogens were not associated with the presence of WVD symptoms (3,4). By 2006, other watermelon fields were also affected. Field trials in 2007 and 2008 with insect-proof cages and insecticides suggested a role of whiteflies (Bemisia tabaci) in the transmission of a virus (3,4). Here, we report that watermelon and pumpkin plants were successfully infected in Puerto Rico by mechanical inoculation and through B. tabaci transmission assays, similarly to transmissions previously conducted in Florida with Squash vein yellowing virus (SqVYV) (1). In addition, plants of Cucurbita moschata exhibited vein clearing symptoms typical of SqVYV after mechanical inoculation with extracts from watermelon plants with WVD symptoms. In 2011, eight watermelon samples from plants exhibiting WVD syndrome were collected in Guánica, Santa Isabel, Juana Díaz, and Mayagüez, and two Momordica charantia samples were collected from Mayagüez. RNA was extracted from all 10 original samples, as well as from plants that were used in mechanical and vector transmission assays, using RNeasy Plant Mini Kit (Qiagen, Valencia, California), and all samples were found positive for SqVYV by reverse transcription-PCR, using previously described primers and methods (1,2). In all cases, a single ~1-kb PCR fragment was revealed, and PCR fragments from four samples were selected for direct sequencing. All sequences showed high levels (>99%) of nucleotide identity with SqVYV sequences from Florida (JF897989, JF897985, and JF897984). Sequences of the SqVYV CP gene from Puerto Rico were deposited in GenBank under accession numbers KC713961 to KC713964. To our knowledge, this is the first report of SqVYV in Puerto Rico associated with WVD syndrome in cucurbits, and thus has implications for management of viral diseases of watermelon in the Caribbean. This is also the first detection of SqVYV outside of the continental United States in both watermelon and a wild species, M. charantia (bitter gourd). References: (1) S. Adkins et al. Phytopathology 97:145, 2007. (2) S. Adkins et al. Plant Dis. 92:1119, 2008. (3) C. Estévez de Jensen et al. Phytopathology 98:S52, 2008. (4) L. Polanco-Florián. El marchitamiento súbito de la sandía [Citrullus lanatus (Thumb.) Matsum & Nakai]. M.S. thesis, University of Puerto Rico, Mayagüez, PR, 2009.

scholarly journals Phosphorus status of soils from the poultry zone in Puerto Rico

1969 ◽  
Vol 83 (1-2) ◽  
pp. 1-17
Author(s):  
Gustavo A. Martínez ◽  
Luis Olivieri ◽  
José A. Castro ◽  
Oscar Muñiz-Torres ◽  
José L. Guzmán
Keyword(s):  
Puerto Rico ◽  
Management Practices ◽  
Poultry Production ◽  
Surrounding Water ◽  
Nutrient Runoff ◽  
Bird Populations ◽  
South Central ◽  
Environmentally Sound ◽  
Sound Management ◽  
The Impact

The poultry industry is the economic backbone of the south central region of Puerto Rico. However, as in other poultry production regions in the U.S., concern has risen regarding its potentially damaging impact on the environment. Eutrophication of rivers and lakes, induced by excessive nutrient runoff, has forced regulatory agencies to closely evaluate manure disposal practices. Thus, the need is critical for environmentally sound management practices in poultry producing areas. The impact of years of manure applications on the nutritional status of soils was ascertained by evaluating a number of samples from nine poultry farms of Puerto Rico. The farms were selected among those with the highest bird populations. Sixty-seven percent of the samples analyzed contained phosphorus levels (Olsen) in excess of what is considered adequate to support crop growth. Fifty-six percent of these exceeded levels considered by some states as critical for water quality purposes. Measured levels ranged from undetectable values up to 900 mg/kg P.  A diagnostic tool known as the P index was used in an effort to identify areas of concern. According to this criterion, all farms studied had zones where nutrient runoff could threaten the quality of the surrounding water bodies.

ELEVATED MID-CRETACEOUS PALAEOTEMPERATURES IN THE WESTERN OTWAY BASIN: CONSEQUENCES FOR HYDROCARBON GENERATION MODELS

1997 ◽  
Vol 37 (1) ◽  
pp. 505 ◽  
Author(s):  
M.M. Mitchell
Keyword(s):  
Upper Cretaceous ◽  
Vitrinite Reflectance ◽  
Geothermal Gradient ◽  
Hydrocarbon Generation ◽  
Key Factors ◽  
Factors Affecting ◽  
Early Maturation ◽  
Maximum Temperatures ◽  
Hydrocarbon Preservation ◽  
Uplift And Erosion

The Otway Basin formed during the Mesozoic separation of Antarctica and Australia. A study of apatite fission track (FT) analysis and vitrinite reflectance (VR) data from borehole samples in the western Otway Basin was initiated to elucidate some of the thermal and structural complexities of this region.Interpretation of results suggest that some areas experienced regionally elevated palaeotemperatures, however, much of the region is at present-day maximum temperatures. Where cooling from maximum palaeotemperatures is observed, the timing may be grouped over three main intervals as follows; mid-Cretaceous, Late Cretaceous to Early Tertiary, and Tertiary. Cooling was facilitated by a decline in geothermal gradient, uplift and erosion, or both. Evidence for a decline in geothermal gradient from values >55°C/km in the mid- Cretaceous is recognised in several wells. Elevated mid- Cretaceous palaeogeothermal gradients (50−60°C/km) have been reported for the eastern Otway Basin, suggesting that these high temperatures were a regional phenomena. Cooling by uplift and erosion at this time was minimal throughout the western Otway Basin in contrast to the kilometre scale uplift and erosion reported for the eastern Otway Basin and adjacent basement inland of this section of the rift.The relative early maturation of the Otway Supergroup during mid-Cretaceous regionally elevated geothermal gradients, and subsequent basin restructuring, are key factors affecting hydrocarbon preservation in the western Otway Basin. Strategies for identification of prospective areas include identification of regions that have remained at moderate temperatures during the Early Cretaceous, and have not undergone burial under a thick Upper Cretaceous to Tertiary section.

Estimation of subsurface formation temperature in the Upper Yangtze Area, Southwest China

2020 ◽  
Author(s):  
Xianglan Li ◽  
Shaowen Liu ◽  
Ming Xu
Keyword(s):  
Shale Gas ◽  
Southwest China ◽  
Geothermal Gradient ◽  
Temperature Data ◽  
Hydrocarbon Generation ◽  
Formation Temperature ◽  
Geothermal Regime ◽  
The Mean ◽  
Yangtze Area ◽  
Subsurface Formation

<p>Subsurface formation temperature in the upper Yangtze area, southwest China, is significant for assessment of hydrocarbon generation and preservation, especially that of shale gas. The upper Yangtze area, with well-developed marine carbonate rocks, is one of the important preferred areas of shale gas exploration and development in China. Previous studies have analyzed the accumulation mechanism, development characteristics, hydrocarbon generation potential and occurrence modes of shale gas. However, the analysis of subsurface formation temperature is rare due to a lack of highly accurate temperature data. Here we combined new steady-state temperature logging data, drill-stem test temperature data and measured rock thermal properties, to investigate the geothermal regime and to estimate the formation temperature at specific depths in the range 1000~6000 m in this area.</p><p>Our results show that the present-day geothermal gradient for this area ranges from 10 to 74℃/km, with a mean of 24℃/km; While the heat flow varies from 27 to 118mW/m<sup>2</sup>, with a mean of 64mW/m<sup>2</sup>, indicating a moderate-high geothermal regime. Formation temperature at the depth of 1000 m is estimated to be between 26 °C and 71°C, with a mean of 40°C; the temperature at 2000 m ranges from 36~125°C with an average of 64°C; 45~180°C is for that at the depth of 3000 m, and the mean is 88°C; the temperature at 4000 m varies from 88 to 235°C, with a mean of 112°C; 65~290°C is for that at 5000 m depth, with a mean of 136°C; 75~344°C is for that at the depth of 6000 and the mean is 160°C. Generally, the pattern of the estimated subsurface temperatures in different depths is similar and has an obvious sub-area characterization, showing a trend of gradually increasing of temperature from northeast to southwest area. Most areas in the south and southeast of Sichuan Basin are with moderate temperature area, which maybe is the “sweet spot area” for shale gas exploration.</p>

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